fix(deps): update composebom to v2026.06.00

renovatebot/github-action is a Node wrapper that shells out to
`docker run ghcr.io/renovatebot/renovate`, requiring a Docker CLI + socket
inside the job. The Gitea runner executes the job in a plain node:22 container
with neither, so it died on "Unable to locate executable file: docker".

Run the renovate image as the job container and invoke `renovate` directly —
drops the docker-in-docker requirement. Full tag pinned; Renovate's
github-actions manager keeps container.image bumped.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitea/workflows/ci.yaml

@@ -6,7 +6,11 @@ on:
       - '**'
     tags-ignore:
       - '**'
-  pull_request:
+
+# Cancel superseded runs on the same branch.
+concurrency:
+  group: ci-${{ github.ref }}
+  cancel-in-progress: true
 
 jobs:
   ci:
@@ -26,30 +30,25 @@ jobs:
 
       - name: Setup Android SDK
         uses: android-actions/setup-android@v3
+        with:
+          # Default ("tools platform-tools") drags in the Android Emulator
+          # (~300 MB) which the build never uses.
+          packages: ''
+
+      - name: Setup Android SDK cache
+        uses: actions/cache@v4
+        with:
+          path: /opt/android-sdk
+          key: ${{ runner.os }}-android-sdk-37-36.0.0
 
       - name: Install Android SDK packages
         run: |
           yes | sdkmanager --licenses >/dev/null || true
           sdkmanager \
             "platform-tools" \
-            "platforms;android-36" \
             "platforms;android-37.0" \
             "build-tools;36.0.0"
 
-      - name: Install jq
-        run: |
-          set -e
-          SUDO=""
-          if command -v sudo >/dev/null 2>&1; then
-            SUDO="sudo"
-          fi
-          if command -v apt-get >/dev/null 2>&1; then
-            $SUDO apt-get update
-            $SUDO apt-get install -y jq
-          elif command -v apk >/dev/null 2>&1; then
-            $SUDO apk add --no-cache jq
-          fi
-
       - name: Setup Gradle cache
         uses: actions/cache@v4
         with:
@@ -63,16 +62,19 @@ jobs:
       - name: Grant execute permission for gradlew
         run: chmod +x ./gradlew
 
+      # No --no-daemon: the daemon lives only as long as this job container
+      # and lets the following steps skip JVM startup + reconfiguration.
       - name: Lint (debug variant only)
-        run: ./gradlew lintDebug --no-daemon
+        run: ./gradlew lintDebug
 
       - name: Unit tests
-        run: ./gradlew testDebugUnitTest --no-daemon
+        run: ./gradlew testDebugUnitTest
 
       - name: Assemble debug APK
-        run: ./gradlew assembleDebug --no-daemon
+        run: ./gradlew assembleDebug
 
       - name: Trivy filesystem scan
+        if: github.ref == 'refs/heads/main'
         run: |
           set -e
           SUDO=""

.gitea/workflows/release.yaml

@@ -1,4 +1,4 @@
-name: Build and Release to F-Droid
+name: Release — F-Droid repo + Gitea release
 
 on:
   push:
@@ -24,16 +24,33 @@ jobs:
 
       - name: Setup Android SDK
         uses: android-actions/setup-android@v3
+        with:
+          packages: ''
+
+      - name: Setup Android SDK cache
+        uses: actions/cache@v4
+        with:
+          path: /opt/android-sdk
+          key: ${{ runner.os }}-android-sdk-37-36.0.0
 
       - name: Install Android SDK packages
         run: |
           yes | sdkmanager --licenses >/dev/null || true
           sdkmanager \
             "platform-tools" \
-            "platforms;android-36" \
             "platforms;android-37.0" \
             "build-tools;36.0.0"
 
+      - name: Setup Gradle cache
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties', 'gradle/libs.versions.toml') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
       - name: Grant execute permission for gradlew
         run: chmod +x ./gradlew
 
@@ -42,10 +59,10 @@ jobs:
       # any tag-resolved drift (e.g. version code substitution issues).
 
       - name: Unit tests
-        run: ./gradlew testDebugUnitTest --no-daemon
+        run: ./gradlew testDebugUnitTest
 
       - name: Assemble debug APK (sanity)
-        run: ./gradlew assembleDebug --no-daemon
+        run: ./gradlew assembleDebug
 
   build-and-deploy:
     needs: ci
@@ -65,16 +82,33 @@ jobs:
 
       - name: Setup Android SDK
         uses: android-actions/setup-android@v3
+        with:
+          packages: ''
+
+      - name: Setup Android SDK cache
+        uses: actions/cache@v4
+        with:
+          path: /opt/android-sdk
+          key: ${{ runner.os }}-android-sdk-37-36.0.0
 
       - name: Install Android SDK packages
         run: |
           yes | sdkmanager --licenses >/dev/null || true
           sdkmanager \
             "platform-tools" \
-            "platforms;android-36" \
             "platforms;android-37.0" \
             "build-tools;36.0.0"
 
+      - name: Setup Gradle cache
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*', '**/gradle-wrapper.properties', 'gradle/libs.versions.toml') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
       - name: Install jq
         run: |
           set -e
@@ -87,7 +121,12 @@ jobs:
             $SUDO apk add --no-cache jq
           fi
 
+      # Tag-only build steps. On a manual workflow_dispatch (ref = a branch,
+      # not a tag) these are skipped: the job then just re-signs the existing
+      # index with the configured repo key and re-uploads — used for key
+      # rotation / repo recovery without publishing a new APK.
       - name: Set version from git tag
+        if: startsWith(github.ref, 'refs/tags/')
         run: |
           set -e
           RAW_TAG="${GITHUB_REF_NAME:-${GITHUB_REF##*/}}"
@@ -101,8 +140,12 @@ jobs:
           sed -i "s/versionName = \".*\"/versionName = \"$VERSION\"/" app/build.gradle.kts
           sed -i "s/versionCode = .*/versionCode = $VERSION_CODE/" app/build.gradle.kts
           grep -E 'versionName|versionCode' app/build.gradle.kts
+          # Export for later steps (F-Droid changelog, mapping asset name).
+          echo "VERSION=$VERSION" >> "$GITHUB_ENV"
+          echo "VERSION_CODE=$VERSION_CODE" >> "$GITHUB_ENV"
 
       - name: Setup Android Keystore
+        if: startsWith(github.ref, 'refs/tags/')
         env:
           KEYSTORE_BASE64: ${{ secrets.KEYSTORE_BASE64 }}
           KEY_PASSWORD: ${{ secrets.KEY_PASSWORD }}
@@ -121,7 +164,8 @@ jobs:
         run: chmod +x ./gradlew
 
       - name: Build release APK
-        run: ./gradlew assembleRelease --no-daemon
+        if: startsWith(github.ref, 'refs/tags/')
+        run: ./gradlew assembleRelease
 
       - name: Setup F-Droid Server Tools
         run: |
@@ -131,29 +175,48 @@ jobs:
           $SUDO apt-get install -y sshpass python3-pip
           pip3 install --break-system-packages --upgrade fdroidserver
 
-      - name: Initialize or fetch F-Droid Repository
+      - name: Fetch existing F-Droid repo from Hetzner
         env:
           HOST: ${{ secrets.HETZNER_HOST }}
           USER: ${{ secrets.HETZNER_USER }}
           PASS: ${{ secrets.HETZNER_PASS }}
         run: |
+          set -euo pipefail
+          SSH_OPTS="-o StrictHostKeyChecking=no -o ConnectTimeout=20"
           mkdir -p fdroid
-          sshpass -p "$PASS" sftp -o StrictHostKeyChecking=no "$USER@$HOST" <<'SFTP'
-          -mkdir dev
-          -mkdir dev/fdroid
-          -mkdir dev/fdroid/repo
-          SFTP
-          sshpass -p "$PASS" scp -o StrictHostKeyChecking=no -r "$USER@$HOST:dev/fdroid/." fdroid/ || (cd fdroid && fdroid init)
+          # Pull only the published repo/ (all apps' APKs), any per-app
+          # metadata, and the repo icon — enough to rebuild the index without
+          # dropping the other apps. The signing key is deliberately NOT pulled
+          # from the box; it comes from CI secrets in the next step so it never
+          # has to live in the web-served tree.
+          sshpass -p "$PASS" scp $SSH_OPTS -r "$USER@$HOST:dev/fdroid/repo" fdroid/ 2>/dev/null || true
+          sshpass -p "$PASS" scp $SSH_OPTS -r "$USER@$HOST:dev/fdroid/metadata" fdroid/ 2>/dev/null || true
+          sshpass -p "$PASS" scp $SSH_OPTS "$USER@$HOST:dev/fdroid/icon.png" fdroid/ 2>/dev/null || true
+          mkdir -p fdroid/repo fdroid/metadata
 
-      - name: Ensure F-Droid repo signing key and icon
+      - name: Restore F-Droid signing key and config from secrets
+        env:
+          FDROID_KEYSTORE_BASE64: ${{ secrets.FDROID_KEYSTORE_BASE64 }}
+          FDROID_CONFIG_BASE64: ${{ secrets.FDROID_CONFIG_BASE64 }}
         run: |
-          cd fdroid
-          mkdir -p repo/icons
-          if [ ! -f keystore.p12 ]; then
-            fdroid update --create-key
+          set -euo pipefail
+          # Fail loudly if the repo key is not configured. NEVER auto-generate
+          # one: a fresh key changes the repo fingerprint and breaks every
+          # user's pinned repo. (Replaces the old `fdroid update --create-key`
+          # path, which silently rotated the key on a wiped server.)
+          if [ -z "${FDROID_KEYSTORE_BASE64:-}" ] || [ -z "${FDROID_CONFIG_BASE64:-}" ]; then
+            echo "ERROR: FDROID_KEYSTORE_BASE64 / FDROID_CONFIG_BASE64 secrets are not set." >&2
+            echo "Refusing to continue — will not auto-generate a new repo key." >&2
+            exit 1
           fi
+          echo "$FDROID_KEYSTORE_BASE64" | base64 --decode > fdroid/keystore.p12
+          echo "$FDROID_CONFIG_BASE64"   | base64 --decode > fdroid/config.yml
+          test -s fdroid/keystore.p12
+          test -s fdroid/config.yml
+          mkdir -p fdroid/repo/icons
 
       - name: Copy new APK to repo
+        if: startsWith(github.ref, 'refs/tags/')
         run: |
           set -e
           mkdir -p fdroid/repo
@@ -169,12 +232,33 @@ jobs:
           mkdir -p fdroid/metadata
           cp -r fdroid-metadata/* fdroid/metadata/
 
+      # Per-version "What's New" for F-Droid clients: the tag's CHANGELOG
+      # section written to changelogs/<versionCode>.txt (same extraction as the
+      # Gitea release notes). en-US only — F-Droid falls back to it for locales
+      # without their own changelog. fdroid update bakes this into the index.
+      - name: Generate F-Droid changelog for this version
+        if: startsWith(github.ref, 'refs/tags/')
+        run: |
+          set -e
+          awk -v ver="$VERSION" '
+            $0 ~ "^## \\[" ver "\\]" { flag = 1; next }
+            /^## \[/ { flag = 0 }
+            flag' CHANGELOG.md > /tmp/changelog.txt
+          sed -i -e '/./,$!d' /tmp/changelog.txt
+          if [ ! -s /tmp/changelog.txt ]; then
+            echo "See CHANGELOG.md for $VERSION." > /tmp/changelog.txt
+          fi
+          CL_DIR="fdroid/metadata/de.jeanlucmakiola.calendula/en-US/changelogs"
+          mkdir -p "$CL_DIR"
+          cp /tmp/changelog.txt "$CL_DIR/${VERSION_CODE}.txt"
+          echo "Wrote $CL_DIR/${VERSION_CODE}.txt"
+
       - name: Generate F-Droid Index
         run: |
           cd fdroid
           fdroid update -c
 
-      - name: Upload Repo to Hetzner
+      - name: Upload repo/ to Hetzner
         env:
           HOST: ${{ secrets.HETZNER_HOST }}
           USER: ${{ secrets.HETZNER_USER }}
@@ -185,6 +269,113 @@ jobs:
           sshpass -p "$PASS" sftp $SSH_OPTS "$USER@$HOST" <<'SFTP'
           -mkdir dev
           -mkdir dev/fdroid
-          -mkdir dev/fdroid/repo
           SFTP
-          sshpass -p "$PASS" scp $SSH_OPTS -r fdroid/. "$USER@$HOST:dev/fdroid/"
+          # Publish the signed repo/ plus metadata/ (descriptions, screenshots,
+          # per-version changelogs) so changelog history survives across
+          # releases. keystore.p12 and config.yml are NEVER uploaded, so they
+          # can't re-enter the web-served tree; nginx serves only repo/ anyway.
+          sshpass -p "$PASS" scp $SSH_OPTS -r fdroid/repo fdroid/metadata "$USER@$HOST:dev/fdroid/"
+
+      # Archive the R8 mapping so user crash stacktraces stay deobfuscatable.
+      # Attached to the Gitea release (it's not an APK, so it fits the
+      # no-binaries rule). Best-effort: never fail a release over it.
+      - name: Attach R8 mapping to Gitea release
+        if: startsWith(github.ref, 'refs/tags/')
+        continue-on-error: true
+        env:
+          TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          API: ${{ github.server_url }}/api/v1/repos/${{ github.repository }}
+        run: |
+          set -e
+          MAP="app/build/outputs/mapping/release/mapping.txt"
+          if [ ! -f "$MAP" ]; then echo "No mapping.txt (R8 off?) — skipping."; exit 0; fi
+          TAG="${GITHUB_REF_NAME:-${GITHUB_REF##*/}}"
+          ASSET="mapping-${VERSION:-$TAG}.txt.gz"
+          gzip -c "$MAP" > "/tmp/$ASSET"
+          # The release is created by the gitea-release job; ensure it exists
+          # (idempotent) so this job doesn't race it to a 404.
+          ID=$(curl -s -H "Authorization: token $TOKEN" "$API/releases/tags/$TAG" | jq -r '.id // empty')
+          if [ -z "$ID" ]; then
+            ID=$(curl -s -X POST -H "Authorization: token $TOKEN" \
+              -H "Content-Type: application/json" \
+              -d "{\"tag_name\":\"$TAG\",\"name\":\"$TAG\"}" \
+              "$API/releases" | jq -r '.id // empty')
+          fi
+          if [ -z "$ID" ]; then echo "Could not resolve release id — skipping."; exit 0; fi
+          # Replace any prior asset of the same name (re-run safe).
+          OLD=$(curl -s -H "Authorization: token $TOKEN" "$API/releases/$ID/assets" \
+            | jq -r --arg n "$ASSET" '.[] | select(.name==$n) | .id')
+          [ -n "$OLD" ] && curl -s -X DELETE -H "Authorization: token $TOKEN" "$API/releases/$ID/assets/$OLD" >/dev/null || true
+          curl -s -X POST -H "Authorization: token $TOKEN" \
+            -F "attachment=@/tmp/$ASSET" \
+            "$API/releases/$ID/assets?name=$ASSET" -o /dev/null -w "asset upload HTTP %{http_code}\n"
+
+  # A Gitea release per tag, carrying the tag's CHANGELOG section as its
+  # notes. Deliberately no APK assets — distribution stays with the F-Droid
+  # repo; the release is the human-readable record. Gated on the tests-only
+  # ci job (not the deploy) so notes appear even if the F-Droid upload has
+  # an infrastructure hiccup.
+  gitea-release:
+    needs: ci
+    if: startsWith(github.ref, 'refs/tags/')
+    runs-on: docker
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Extract changelog section for this tag
+        run: |
+          set -e
+          TAG="${GITHUB_REF_NAME:-${GITHUB_REF##*/}}"
+          VERSION="${TAG#v}"
+          # Everything between "## [<version>]" and the next "## [" heading.
+          awk -v ver="$VERSION" '
+            $0 ~ "^## \\[" ver "\\]" { flag = 1; next }
+            /^## \[/ { flag = 0 }
+            flag' CHANGELOG.md > release-notes.md
+          # Trim leading blank lines.
+          sed -i -e '/./,$!d' release-notes.md
+          if [ ! -s release-notes.md ]; then
+            echo "_No changelog entry for ${VERSION} — see CHANGELOG.md._" > release-notes.md
+          fi
+          echo "--- release notes ---"
+          cat release-notes.md
+
+      - name: Create Gitea release
+        env:
+          TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          API: ${{ github.server_url }}/api/v1/repos/${{ github.repository }}
+        run: |
+          set -e
+          TAG="${GITHUB_REF_NAME:-${GITHUB_REF##*/}}"
+          python3 - "$TAG" <<'PY' > payload.json
+          import json, sys
+          print(json.dumps({
+              "tag_name": sys.argv[1],
+              "name": sys.argv[1],
+              "body": open("release-notes.md").read(),
+              "draft": False,
+              "prerelease": False,
+          }))
+          PY
+          # Upsert: the build-and-deploy job may have created a bare release
+          # first (to attach the mapping asset), so PATCH the notes if it
+          # exists, otherwise POST a new one. Both paths are re-run safe.
+          curl -s -H "Authorization: token $TOKEN" "$API/releases/tags/$TAG" > existing.json
+          ID=$(python3 -c "import json,sys; d=json.load(open('existing.json')); print(d.get('id',''))" 2>/dev/null || true)
+          if [ -n "$ID" ]; then
+            CODE=$(curl -s -o response.json -w '%{http_code}' -X PATCH \
+              -H "Authorization: token $TOKEN" -H "Content-Type: application/json" \
+              -d @payload.json "$API/releases/$ID")
+            OK=200
+          else
+            CODE=$(curl -s -o response.json -w '%{http_code}' -X POST \
+              -H "Authorization: token $TOKEN" -H "Content-Type: application/json" \
+              -d @payload.json "$API/releases")
+            OK=201
+          fi
+          cat response.json
+          if [ "$CODE" != "$OK" ]; then
+            echo "Release upsert failed with HTTP $CODE (expected $OK)"
+            exit 1
+          fi

.gitea/workflows/renovate.yml

@@ -0,0 +1,42 @@
+name: Renovate
+
+on:
+  # Weekly sweep. Mondays 05:00 UTC — this cron owns the cadence; the repo's
+  # renovate.json5 deliberately has no internal schedule (avoids double-gating).
+  schedule:
+    - cron: '0 5 * * 1'
+  # Manual run for an on-demand sweep from the Actions tab.
+  workflow_dispatch:
+
+# Never let two Renovate runs touch the repo at once.
+concurrency:
+  group: renovate
+  cancel-in-progress: false
+
+jobs:
+  renovate:
+    runs-on: docker
+    # Run the Renovate image *as* the job container and invoke the `renovate`
+    # binary directly. The renovatebot/github-action wrapper is a thin Node
+    # action that shells out to `docker run …` — it needs a Docker CLI + socket
+    # inside the job, which the Gitea runner's plain node container has not, so
+    # it died on "Unable to locate executable file: docker". Running the image
+    # directly drops the docker-in-docker requirement entirely.
+    # Full tag pinned; Renovate's github-actions manager keeps it bumped.
+    container:
+      image: ghcr.io/renovatebot/renovate:43.232.0
+    steps:
+      - name: Run Renovate
+        run: renovate
+        env:
+          # Self-hosted Gitea, not github.com.
+          RENOVATE_PLATFORM: gitea
+          RENOVATE_ENDPOINT: https://gitea.jeanlucmakiola.de/api/v1
+          # Bot-account token (Gitea secret). Needs repo read/write + PR scope.
+          RENOVATE_TOKEN: ${{ secrets.RENOVATE_TOKEN }}
+          # Scope to this repo only — no org-wide autodiscovery.
+          RENOVATE_AUTODISCOVER: 'false'
+          RENOVATE_REPOSITORIES: '["makiolaj/calendula"]'
+          # Commits/PRs authored as the bot, not a real maintainer.
+          RENOVATE_GIT_AUTHOR: 'Renovate Bot <renovate@jeanlucmakiola.de>'
+          LOG_LEVEL: info

.gitea/workflows/translations.yaml

@@ -0,0 +1,41 @@
+name: Translations
+
+# Fast, SDK-free parity check for translation resources, so Weblate PRs (which
+# only touch values-*/strings.xml) get quick feedback without the full Android
+# build. The deeper checks still run in CI via lintDebug (ExtraTranslation).
+on:
+  push:
+    branches:
+      - '**'
+    tags-ignore:
+      - '**'
+    paths:
+      - 'app/src/main/res/values*/strings.xml'
+      - 'app/src/main/res/xml/locales_config.xml'
+      - 'scripts/check_translations.py'
+      - '.gitea/workflows/translations.yaml'
+
+concurrency:
+  group: translations-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  check:
+    runs-on: docker
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Ensure python3
+        run: |
+          if ! command -v python3 >/dev/null 2>&1; then
+            if command -v apt-get >/dev/null 2>&1; then
+              apt-get update && apt-get install -y python3
+            elif command -v apk >/dev/null 2>&1; then
+              apk add --no-cache python3
+            fi
+          fi
+          python3 --version
+
+      - name: Check translation parity
+        run: python3 scripts/check_translations.py

.gitignore

@@ -40,6 +40,7 @@ captures/
 # Keystore files
 *.jks
 *.keystore
+*.p12
 /key.properties
 
 # Google Services (e.g. APIs or Firebase)
@@ -50,8 +51,7 @@ google-services.json
 Thumbs.db
 
 # F-Droid local artifacts (the pipeline generates them in CI)
-fdroid/repo/
-fdroid/keystore.p12
+/fdroid/
 
 # KSP
 .ksp/

.planning/PROJECT.md

@@ -2,11 +2,12 @@
 
 ## What This Is
 
-A modern Material 3 Expressive Android calendar app, read-only V1. Lives
-entirely on top of Android's `CalendarContract` — any calendar synced to the
-device (CalDAV via DAVx5, Google, local, WebCal, …) shows up automatically.
-The differentiator is visual: real Material 3 Expressive design that no
-existing FOSS calendar app delivers.
+A modern Material 3 Expressive Android calendar app. Lives entirely on top
+of Android's `CalendarContract` — any calendar synced to the device (CalDAV
+via DAVx5, Google, local, WebCal, …) shows up automatically; creating,
+editing, and deleting writes straight back, and reminders are delivered by
+the app itself (Etar model). The differentiator is visual: real Material 3
+Expressive design that no existing FOSS calendar app delivers.
 
 ## Core Value
 
@@ -15,8 +16,10 @@ re-inventing the calendar sync stack — leave that to DAVx5 and the system.
 
 ## Current Milestone
 
-**v0.1 — Foundation & CI:** Buildable Android project scaffold with theme,
-icon, i18n, Hilt, DataStore, green CI.
+Milestones 1 (read, v1.0) and 2 (write support, v1.1–v2.0.0 incl. reminder
+delivery) are **complete** — v2.0.0 shipped 2026-06-11. Next is v3.0
+(power-user features) plus an undecided "Locations & People" idea backlog;
+see `ROADMAP.md`.
 
 ## Stack
 
@@ -26,9 +29,8 @@ Expressive 1.5.0-alpha21 (alpha is intentional — Expressive APIs only
 live in the 1.5 alpha line). Hilt 2.59.2, DataStore. Gradle Kotlin DSL
 with Version Catalog. AGP 9.1.1, Gradle 9.5.1. JVM target 17.
 
-Read-only V1, write support V2.
-
-Android-only (minSdk 29, targetSdk 36). No iOS.
+Android-only (minSdk 29, targetSdk 36). No iOS. No `INTERNET` permission —
+any feature that would need one is an explicit product decision first.
 
 ## Naming
 

.planning/REQUIREMENTS.md

@@ -2,36 +2,43 @@
 
 See full design spec: `docs/superpowers/specs/2026-06-08-calendar-app-design.md`
 
-## V1 Scope (Variant "B")
+## V1 Scope (Variant "B") — shipped in full (v1.0.0, 2026-06-11)
 
-### Validated (shipped)
-- Foundation & CI infrastructure — v0.1.0 (2026-06-08)
-
-### Active (V1)
-
-- [x] Foundation & CI infrastructure
+- [x] Foundation & CI infrastructure — v0.1.0 (2026-06-08)
 - [x] Data Layer over `CalendarContract`
 - [x] Permission flow (`READ_CALENDAR`)
-- [ ] Month view (S1)
-- [ ] Week view (S2)
-- [ ] Day view (S3)
-- [ ] Event Detail Sheet (S4)
-- [ ] Multi-Calendar Filter (M3)
-- [ ] Today button + Jump-to-Date (M2)
-- [ ] View-Switcher (M1)
-- [ ] Settings screen (M4)
-- [ ] Empty / no-permission / no-calendars states
-- [ ] German + English localization
-- [ ] Loading/Failure/Success states per screen (architectural pattern)
+- [x] Month view (S1)
+- [x] Week view (S2)
+- [x] Day view (S3)
+- [x] Event Detail Sheet (S4) — became a full screen, plus full event read (v0.6)
+- [x] Multi-Calendar Filter (M3)
+- [x] Today button (M2) — shipped v0.5; Jump-to-Date **cut from scope**
+- [x] View-Switcher (M1)
+- [x] Settings screen (M4)
+- [x] Empty / no-permission / no-calendars states
+- [x] German + English localization
+- [x] Loading/Failure/Success states per screen (architectural pattern)
 
-### Out of Scope (V2+)
+## V2 Scope — write support, shipped in full (v2.0.0, 2026-06-11)
+
+- [x] Write foundation: `WRITE_CALENDAR`, read-only-calendar detection, delete (v1.1)
+- [x] Create event: form, FAB, last-used calendar (v1.2; polish v1.2.1)
+- [x] Edit event: shared form, scoped recurring writes, recurrence picker (v1.3)
+- [x] Reminder notifications (v1.4) — **reversal of the original
+  "system handles reminders" assumption:** Calendula targets
+  sole-calendar-app users, so it posts reminder notifications itself
+  (Etar model), incl. `POST_NOTIFICATIONS` onboarding
+- [x] Conflict dialog on save + store polish (v2.0)
+- Quick-add — **cut from scope** (the prefilled form covers it)
+- Calendar switching while editing — moved to v3 backlog
+
+### Out of Scope (V3+)
 
-- Event create / edit / delete (V2)
 - Home-screen widget
 - Full-text search
-- Quick-add
-- Custom notifications/reminders (system already handles these)
 - Tablet/foldable-specific layouts
+- Locations & People ideas (contact picker, OSM autocomplete) — see
+  `ROADMAP.md` idea backlog, undecided
 - iOS support (Android-only by design)
 
 ## Constraints

.planning/ROADMAP.md

@@ -6,27 +6,462 @@
 |---|---|---|
 | v0.1 | Foundation & CI | complete |
 | v0.2 | Data Layer & Permission Flow | complete |
-| v0.3 | Month view | in progress |
-| v0.4 | Week view | in progress |
-| v0.5 | Day view | pending |
-| v0.6 | Event Detail Sheet | pending |
-| v0.7 | Filter & Settings | pending |
+| v0.3 | Month + Week + Day views, view switcher | complete |
+| v0.4 | Event Detail (S4) + humanized recurrence | complete |
+| v0.5 | Calendar filter (M3) + Settings (M4) | complete |
+| v0.6 | Full event read — surface every readable field | complete |
+| v1.0 | First public release — polish pass, F-Droid | complete |
 
-## v1.0 — First Public Release
+Delivery ran ahead of the original table: Day view (S3) shipped in v0.3 and
+Event Detail (S4) in v0.4, so the Filter/Settings milestone became v0.5.
 
-All V1 features shipped, polished, on F-Droid. Read-only calendar.
+Jump-to-date (the date-picker half of M2) was **cut from scope** and will not
+ship. The "Today" half of M2 already shipped in v0.5 (drawer entry).
 
-## v2.0 — Write Support
+## v0.6 — Full event read
 
-- Event create / edit / delete via `CalendarContract` writes
-- Quick-add sheet
-- Conflict UX (event modified externally during edit)
+Round out the read-only model so a detail view shows everything the system
+actually stores, before write support starts. Scope = `CalendarContract`
+columns we don't yet read/display:
 
-## v3.0 — Power-User Features
+- **Reminders** (`VALARM`) — read `CalendarContract.Reminders`, list lead times
+- **Status** — Confirmed / Tentative / Cancelled (cancelled shown struck-through)
+- **Availability** (`TRANSP`) — Free / Busy chip
+- **Attendee extras** — role (required / optional / organizer) + the user's own
+  `SELF_ATTENDEE_STATUS`
+- **Timezone** (`EVENT_TIMEZONE`) — shown only when it differs from the device zone
+- **URL** — ~~tappable link card~~ **cut**: `CalendarContract` exposes no
+  `Events.URL` column (only `CUSTOM_APP_URI`, an originating-app deep-link).
+  URLs are instead surfaced by linkifying the description text
+- **Access level / class** (private / confidential) — small chip (optional, trivial)
 
-- Home-screen widget
-- Full-text search
-- Tablet / foldable layouts
-- Optional: ICS file import (drag-and-drop)
+All of the above shipped in v0.6.0 (2026-06-11).
 
-Order is indicative — community feedback after V1 may re-prioritize.
+Deliberately out of v0.6:
+- Recurrence exception / modified-occurrence badges — `Instances` already
+  resolves correct per-occurrence times for display; this only matters for
+  editing, so it folds into v2
+- `CATEGORIES`, `ATTACH` — not reliably exposed by `CalendarContract`
+  (provider limitation, not our choice)
+
+## v1.0 — First Public Release — shipped 2026-06-11
+
+All V1 features shipped, polished, on F-Droid. Read-only calendar. Cut directly
+after v0.6 (full event read) plus the onboarding-screen polish pass.
+
+### Polish backlog (pre-1.0)
+- ~~Redesign the initial grant-access (permission) screen~~ — **done**
+  (Material 3 Expressive onboarding, shipped in v0.6.0 / v1.0.0)
+
+## v2.0 — Write Support (complete, shipped 2026-06-11)
+
+Delivered in four releasable slices (plan:
+`docs/superpowers/plans/2026-06-11-03-write-support.md`). The V1 spec is a
+guide here, not a contract — scope per slice is decided as we go.
+
+| Version | Milestone | Status |
+|---|---|---|
+| v1.1 | Write foundation — `WRITE_CALENDAR`, read-only-calendar detection, delete (series + single occurrence) | complete (shipped 2026-06-11) |
+| v1.2 | Create event — form, FAB, last-used-calendar preselect | complete (shipped 2026-06-11) |
+| v1.2.1 | Form polish after on-device review — card design system, optional fields + settings defaults, OptionCard dialogs, expressive motion | complete (shipped 2026-06-11) |
+| v1.3 | Edit event — shared form, scoped recurring writes (this / following / all), recurrence picker | complete (shipped 2026-06-11) |
+| v1.4 | Reminder notifications — see below | complete (shipped 2026-06-11) |
+| v2.0 | Conflict dialog, polish pass (store copy refresh, F-Droid screenshots), release | complete (shipped 2026-06-11) |
+
+v2.0 scope was re-cut on 2026-06-11, after v1.4:
+- **Occurrence edit** already shipped early, in v1.3.
+- **Quick-add** is **cut from scope**: the full form already opens prefilled
+  (visible day, last-used calendar, optional fields hidden), so the sheet
+  would only save one screen transition while adding a second create-surface
+  to maintain. Revisit only if real-world feedback says creation feels heavy.
+- **Calendar switching while editing** moves to the v3 backlog (sync-adapter
+  minefield: `CALENDAR_ID` is sync-adapter-owned, AOSP locks the field; an
+  honest implementation is copy+delete like Google Calendar, with sync-identity
+  and attendee side effects).
+- **Conflict dialog** stays (plan 03, decision 5): on save, compare against
+  the row as it was when the form loaded; on external change, ask
+  overwrite / discard. Closes the silent-clobber gap on synced calendars.
+
+## v1.4 — Reminder Notifications
+
+**Essential**, not nice-to-have: Calendula targets users for whom it is their
+*only* calendar app, so reminder delivery can't be delegated to Google/OEM
+Calendar. The calendar provider schedules reminders and broadcasts
+`android.intent.action.EVENT_REMINDER`, but it does **not** post the visible
+notification — a calendar app must. We become that app (the Etar model).
+
+Scope:
+- Manifest-registered `BroadcastReceiver` for `EVENT_REMINDER`
+  (data scheme `content://com.android.calendar`) — wakes us at reminder time,
+  no foreground service.
+- Read `CalendarContract.CalendarAlerts` / `Reminders`, filter to
+  `METHOD_ALERT` / `METHOD_DEFAULT` (skip `METHOD_EMAIL`); post on a dedicated
+  notification channel; tap opens event detail.
+- `POST_NOTIFICATIONS` runtime permission (API 33+) — requested in onboarding.
+- Onboarding step: (a) request `POST_NOTIFICATIONS`, (b) in-app reminders
+  toggle, **default ON**, with copy warning that a second calendar app with
+  notifications on will cause duplicate reminders. Mirrored into Settings
+  (reversible).
+
+Deliberately deferred (add only if needed):
+- Snooze / dismiss notification actions (Etar has them)
+- Battery-optimization exemption prompt for delivery reliability
+
+## v2.1 — Month event grid + drawer view tabs (shipped 2026-06-15)
+
+- Month grid shows real events as continuous multi-day bars (not just dots)
+- View section in the navigation drawer to switch Month / Week / Day
+- Fix: text cursor no longer jumps in event text fields
+
+## v2.2 — Tap-to-create + local calendar management (shipped 2026-06-16)
+
+- Tap an empty slot in day/week → create form prefilled with that day + the
+  tapped hour (snapped to the hour, 1 h long)
+- Local (device-only) calendar management in a full-screen editor from
+  Settings → Calendars: create / rename / recolor / delete, with name,
+  pastel-previewed colour, and description (stored in `CAL_SYNC1`)
+- Synced calendars listed read-only, grouped by account, each with a
+  per-account "manage in source app" deep-link (resolved from the account's
+  authenticator — DAVx5/ICSx5/…) + an add-account shortcut
+- Shared `InlineTextField` extracted to `ui.common` (event form + calendar
+  editor share one input style)
+
+## v2.3 — Material 3 grouped-list redesign (shipped 2026-06-16)
+
+A structural + visual pass adopting one shared blueprint (modelled on the ReFra
+gallery app) across Settings, the calendar manager and the navigation drawer.
+
+- Shared `ui/common/GroupedList.kt`: `CollapsingScaffold` (a `LargeTopAppBar`
+  whose title collapses on scroll) + `GroupedRow` (Position-based corner
+  grouping, press-animated corners, `selected` + `minHeight` knobs).
+- Settings: category hub with About card on top and sliding sub-pages
+  (Appearance / New event form / Notifications); theme/week-start/language
+  pickers moved from `DropdownMenu` to OptionCard dialogs; token-based icon
+  chips; `ic_gitea.xml` for the About "Source" button.
+- Calendar manager + drawer restyled to match; shared `CalendarColorChip`;
+  drawer scrolls as one with the active view highlighted.
+- Cards use `surfaceContainerHigh` for readable contrast.
+- Donate button on the About card deferred (target TBD).
+
+---
+
+# Backlog (theme-based, post-v2.1)
+
+The old v3.0 / "daily-driver polish" / "Locations & People" lists are
+consolidated here by theme. Within a group, **(in progress)** /
+**(next)** mark what is being or about to be worked; everything else is an
+approved-but-unscheduled idea unless tagged **(idea)** /
+**(go/no-go)** / **(rejected)**. Order across groups is not a commitment.
+
+## Near-term sequence (ranked, 2026-06-16)
+
+The theme groups below are the full menu; this is the committed *order* for
+the next stretch. Ranking favours finishing the current create/edit + calendar
+arc before opening new fronts, then cheap-relative-to-value items and ones that
+unblock a later item. Order is a plan, not a contract — revisit after each lands.
+
+**Tier 1 — finish the current arc (create/edit + calendars)**
+1. Tap-to-create in day/week *(shipped v2.2.0)* — prefilled create from an empty slot
+2. Local calendar management + "manage in source app" deep-links *(shipped v2.2.0)*
+3. ~~Settings redesign & restructure~~ *(shipped v2.3.0 — grew into the full
+   grouped-list blueprint across Settings + calendars + drawer; see "v2.3"
+   above)*
+4. ~~Per-event color~~ *(shipped v2.4.0)* — palette calendars write
+   `EVENT_COLOR_KEY` (sync-safe); local/opted-in calendars write a raw
+   `EVENT_COLOR`; off-by-default setting for no-palette synced calendars
+Tier 1's create/edit + calendars arc is effectively closed. **Duplicate event**
+was deprioritised (2026-06-17) as low-importance and dropped to the bottom of
+the sequence; the next item is now **Jump-to-date** (formerly Tier 2).
+
+(Tier 2+ numbering below shifts accordingly; ranking unchanged.)
+
+### Settings redesign & restructure *(shipped v2.3.0)*
+
+The original scope below is kept as a record; the implementation expanded from a
+sub-screen restructure into the shared grouped-list blueprint (see "v2.3" above).
+
+The settings screen has grown into a flat vertical scroll of divider-separated
+sections (Appearance, Event form, Notifications, Calendars, Language, About) and
+will keep accreting rows (per-event-color defaults, default reminder, more
+calendar entries are all queued). It needs structure before it gets unwieldy.
+
+**Decided (2026-06-16): sub-screens**, not flat-but-carded. The top level
+becomes a category list; each category opens its own destination. More
+M3-idiomatic for a settings surface that will keep growing, and it mirrors the
+existing Calendars row, which already navigates out to its own screen.
+
+Structure — top-level settings list → category destinations:
+- **Appearance** → theme, dynamic colour, week start
+- **Event form** → the 6 default-field toggles + the hint text
+- **Notifications** → reminders toggle (POST_NOTIFICATIONS flow stays)
+- **Calendars** → already its own screen (`CalendarsScreen`); just becomes a
+  peer category row, no change to that screen
+- **Language** → single control; keep as a top-level row that opens an
+  OptionCard directly (a whole sub-screen for one choice is overkill)
+- **About** → kept inline on the top-level list as a card (read-only info,
+  not worth a navigation hop). Card layout, top → bottom:
+  - **Identity** — app logo + name "Calendula", with "by Jean-Luc Makiola"
+    as a subtitle beneath the name
+  - **Action buttons** (small, button-styled, sit in a row):
+    - **Source** — Gitea logo, opens the repo (`about_source_url`)
+    - **License** — opens the LICENSE file on Gitea
+    - **Donate** *(tentative)* — sits next to Source; target TBD (decide
+      before building: Liberapay / Ko-fi / Gitea sponsor / etc.)
+  - **Version** — small version number at the bottom of the card
+
+Scope:
+- **Navigation** — add the settings sub-screen destinations alongside the
+  existing settings/calendars routes in `CalendarHost`; back pops to the
+  settings list (mind the existing `BackHandler` that guards against falling
+  through to the activity).
+- **Fix the dialog-pattern violation** — theme, week-start and language use
+  `DropdownMenu`; the project default is the full-width tonal OptionCard modal
+  (radio/dropdown/text-list dialogs are banned, see
+  `option-card-modal-style-default`). Migrate these selectors to OptionCard.
+- **Visual pass** — top-level category rows with leading icons; consistent
+  spacing and row affordances aligned with the event-form card design system.
+
+Out of scope (no new settings *features* here) — this is a structure + style
+pass on the existing controls; new toggles ride in with their own features.
+
+**Tier 2 — navigation & daily-driver completeness**
+5. ~~Jump-to-date — drawer date picker (un-cut from V1); cheap, fills the nav gap~~ *(done, v2.5.0)*
+6. ~~Agenda view — the missing 4th view; serves daily-driver users *and* becomes the data source for the widget~~ *(done, v2.5.0)*
+
+**Tier 3 — platform reach (depends on Tier 2)**
+7. ~~Home-screen widget — built on the agenda data source from #6~~ *(done, v2.5.0 — agenda + month widgets)*
+8. App shortcuts: ~~launcher long-press → New event~~ *(done, v2.5.0)*; optional quick-settings tile still open
+
+**Tier 4 — reliability, data-safety & interop** *(re-ranked 2026-06-17)*
+9. **Reminders — defaults + delivery reliability** *(shipped v2.6.0)* — global
+   default reminder **+ per-calendar override**, bundled with battery-exemption
+   hardening. Full sketch in "Reminders — defaults & delivery reliability" below.
+10. **The `.ics` engine — export + import** *(in progress → v2.7)* — one
+    hand-rolled serializer/parser (zero deps, stays on `kotlinx-datetime`),
+    four surfaces: single-event share + whole-calendar backup (export),
+    open-`.ics`→form + whole-calendar restore (import). Closes the
+    device-local-calendar data-loss gap (#10/#11 merged here). Built as **two
+    sequential branches in one release**: `feat/ics-export` (write side +
+    UID-on-create precursor) then `feat/ics-import` (parser, restore, dedup).
+    Import is liberal-in/strict-out: skip-and-report foreign `VTIMEZONE` /
+    `RECURRENCE-ID` it can't model. Timezone rule: all-day `VALUE=DATE`,
+    non-recurring timed UTC `Z`, recurring timed `TZID`-labelled from the stored
+    `EVENT_TIMEZONE` (no `VTIMEZONE` blocks; resolved against the OS tz DB on
+    import). Plan: `docs/superpowers/plans/2026-06-18-05-ics-export.md`.
+11. **Snooze / dismiss notification actions** *(next, after v2.7)* — follows the
+    `.ics` work; inherits v2.6's deferred exact-alarm/WorkManager decision (snooze
+    must re-fire an alarm).
+12. Drag & drop rescheduling in day/week — big-ticket, own slice (recurring drops reuse the scope dialog)
+
+**Gated — explicit go/no-go before any work (mostly INTERNET-permission calls)**
+- Remote calendar create/edit (re-implements DAVx5; INTERNET + credential storage)
+- Locations & People — contact address picker (no-permission, one-shot) is the safe entry; OSM autocomplete needs INTERNET
+- Move event to another calendar — sync-adapter minefield (copy+delete model)
+
+**Bottom — deprioritised, not important**
+- Duplicate event (detail action → prefilled create form) — moved here
+  2026-06-17; cheap but low value, pick up only if asked
+
+**Unranked / fill-in** — pinch-to-zoom time scale, tablet/foldable layouts,
+full-text search, ICS file import. Pulled in opportunistically, not sequenced.
+
+Debatable calls worth a second look: whether **local-calendar backup (#10)**
+should lead Tier 4 outright (it's a silent data-loss risk, not a feature);
+whether drag-drop (#12) jumps ahead given its daily-driver impact.
+
+## Navigation & views
+
+- ~~Tap an empty slot in day/week → create form prefilled with that
+  date+time, snapped to the hour~~ **shipped v2.2.0** (long-press variant
+  not added — single tap covers it)
+- Agenda view (fourth view: upcoming events grouped by day; also the
+  natural data source for a future widget)
+- Jump to date — drawer date picker (un-cut from V1)
+- Current-time "now" line in day/week — standard in every calendar, cheap,
+  currently absent. Daily-driver polish.
+- Week numbers in the **month** grid — week view already shows the badge
+  (`WeekNumberBadge`, `WeekScreen.kt`); extend to month for ISO/European users.
+- Pinch-to-zoom time scale in day/week
+- Tablet / foldable layouts *(was v3.0)*
+- Full-text search *(was v3.0)* — promote out of "fill-in": for a daily driver
+  with real event history, finding an event is core completeness, not optional.
+
+## Event editing & creation
+
+- Drag & drop rescheduling in day/week (recurring drops reuse the scope
+  dialog) — big-ticket, own slice
+- Duplicate event (detail action → prefilled create form)
+- **Per-event color** (`Events.EVENT_COLOR`, OptionCard picker in the form)
+  *(next)* — chosen to follow the in-progress tap-to-create + calendar
+  management work: reuses the color-picker component and palette plumbing
+  being built for local calendar management, and finishes the create/edit
+  theme. `EVENT_COLOR` / `EVENT_COLOR_KEY` from the calendar's color list
+  (`Colors` table, `TYPE_EVENT`); falls back to the calendar color when unset.
+
+## Calendars & accounts
+
+- ~~Create / manage local (device-only) calendars~~ **shipped v2.2.0** —
+  name + color + description; rename / recolor / delete the calendars the app
+  owns. Inserted under `ACCOUNT_TYPE_LOCAL` as a sync adapter; description in
+  `CAL_SYNC1`. Full-screen "Calendars" editor reached from Settings.
+- ~~Per-calendar "manage in source app" deep-link~~ **shipped v2.2.0** — for
+  synced calendars, open the app the calendar actually came from based on
+  its `ACCOUNT_TYPE` (DAVx5 `bitfire.at.davdroid`, Google `com.google`,
+  …); fall back to system account/sync settings. Plus an "add account"
+  entry into system Accounts. Honest boundary for remote calendars.
+- **Remote calendar create/edit** *(go/no-go)* — creating a CalDAV
+  collection (`MKCALENDAR`) or a Google calendar means an in-app sync
+  client: **INTERNET permission, credential storage, the full server
+  round-trip** — i.e. re-implementing DAVx5. DAVx5 exposes no public
+  intent to delegate the create to it. Cosmetic local edits (color/name)
+  to an existing synced row are possible but don't propagate to the server
+  and may be overwritten on next sync — not promised. Same explicit
+  go/no-go gate as the OSM/INTERNET item below.
+- Move event to another calendar (copy+delete model with a consequences
+  warning — deferred from v2.0; `CALENDAR_ID` is sync-adapter-owned) *(was v3.0)*
+- **Local-calendar backup / export** *(Tier 4 #10)* — device-only
+  (`ACCOUNT_TYPE_LOCAL`) calendars are first-class in Calendula but have **no
+  sync and therefore no backup**: a lost/wiped phone destroys them permanently.
+  Whole-calendar `.ics` (VCALENDAR) export to a user-chosen file (SAF), plus
+  restore-on-import that recreates events into a chosen local calendar. Reuses
+  the .ics serializer from the single-event share work; the restore path reuses
+  the import parser. A data-integrity obligation, not a feature.
+
+## Reminders — defaults & delivery reliability *(implemented 2026-06-17, `feat/default-reminders` — pending on-device review)*
+
+Two themes bundled because both are "make reminders trustworthy" — the core of
+the "Calendula is your only calendar app" promise.
+
+**Built in this slice (A + the safe half of B):** global timed default reminder
++ a **separate all-day default** (day-scale lead times) + per-calendar override
+(timed events), applied on create with manual-edit / calendar-switch / all-day-
+toggle handling; three pickers + per-calendar override list in Settings →
+Notifications; battery-optimisation exemption row (status + system deep-link, no
+extra permission). `resolveDefaultReminder` + prefs round-trips unit-tested.
+Resolution model: all-day events use the all-day global default outright;
+per-calendar overrides govern timed events only. Reviewed (8-angle), fixes
+applied: form-reset state race, label-fn consolidation with the detail screen,
+inline wrapper + single combined flow read.
+
+**Deliberately deferred (documented decisions, not oversights):**
+- *Absolute time-of-day for all-day reminders* — the all-day default is still
+  minutes-before-midnight (day-scale presets), not "9am the day before" (open
+  decision #2's richer half). Per-calendar all-day overrides also deferred.
+- *Self-scheduled alarms* — kept the existing provider-broadcast architecture
+  (open decision #1). The battery exemption is the reliability lever; no
+  `AlarmManager`/`USE_EXACT_ALARM` subsystem was added.
+- *Test-reminder diagnostic* and *battery prompt inside onboarding* — the
+  exemption lives only in Settings for now (onboarding flow untouched to keep
+  the change reviewable).
+
+### A. Default reminders (global + per-calendar override)
+
+**No provider backing.** `CalendarContract` has no column that auto-applies a
+default reminder per calendar — Google's per-calendar defaults live server-side.
+So both the global default *and* the per-calendar override are **app-side
+preferences**, applied by us at event-insert time. We inherit nothing from the
+synced calendar.
+
+- **Storage (DataStore):**
+  - `defaultReminderMinutes: Int?` — global default; `null` = "no reminder".
+  - `defaultAllDayReminderMinutes: Int?` — separate all-day default (all-day
+    reminders are expressed as minutes before midnight / day-before-at-time, not
+    minutes before a start instant — they need their own value).
+  - `perCalendarReminderOverride: Map<Long, Int?>` — keyed by calendar id;
+    **absent key = inherit global**, explicit `null` = "no reminder for this
+    calendar". (Same for an all-day override map if we want per-calendar all-day.)
+- **Apply on create:** a fresh event prefills its reminders list from
+  override-or-global for the preselected calendar. Changing the calendar in the
+  form re-applies the *new* calendar's default **only if the user hasn't manually
+  edited the reminders** — track a dirty flag, mirroring the per-event-color
+  reset pattern (v2.4).
+- **Edit semantics:** defaults apply to **new events only**; never rewrite
+  reminders on existing events on open or on calendar-switch-during-edit.
+- **Settings UI (Notifications sub-page):**
+  - Global default via OptionCard (None / at time of event / 5 / 10 / 15 / 30 min
+    / 1 h / 1 day / custom), plus the separate all-day default.
+  - Per-calendar overrides: a row per writable calendar (in the Calendars screen
+    or a Notifications subsection), each opening the same OptionCard with a
+    leading **"Use global default"** option.
+
+### B. Delivery reliability (exact alarms + battery)
+
+The provider broadcasts `EVENT_REMINDER`, but on modern Android (Doze / OEM
+battery managers) delivery can be silently delayed or dropped. v1.4 deferred this;
+it directly undermines the feature's premise, so it rides in here.
+
+- **Exact alarm — decision first:** trust the provider broadcast, or
+  self-schedule via `AlarmManager.setExactAndAllowWhileIdle` for reliability?
+  If we self-schedule, declare `USE_EXACT_ALARM` (API 33+, auto-granted for
+  calendar/alarm-category apps, F-Droid-clean) with a `SCHEDULE_EXACT_ALARM`
+  fallback for API 31–32 (user-revocable → settings deep-link prompt).
+- **Battery-optimization exemption:** a *soft, optional* prompt via
+  `ACTION_REQUEST_IGNORE_BATTERY_OPTIMIZATIONS` (settings deep-link — never the
+  auto-grant intent), honest copy: "Android may delay reminders to save battery;
+  exempt Calendula for on-time delivery." Shown once after the existing
+  `POST_NOTIFICATIONS` onboarding step, reversible in Settings → Notifications.
+- **Diagnostics:** a "send a test reminder in 1 minute" button in Notifications
+  settings so users can verify delivery on their specific OEM (Samsung / Xiaomi
+  are notorious for suppressing it).
+
+### Open decisions (resolve before building)
+
+1. Self-schedule via `AlarmManager` vs trust the provider broadcast
+   (reliability vs simplicity + battery cost).
+2. All-day reminder representation (minutes-before vs absolute time-of-day).
+3. Where per-calendar overrides live in the UI (rows on the Calendars screen vs
+   a list inside the Notifications sub-page).
+
+### Later (round two)
+
+- Snooze + dismiss actions on the notification (snooze needs an
+  exact-alarm / WorkManager decision) — Tier 4 #13.
+
+## Sharing & interop
+
+- Share event as .ics + open/receive .ics into a prefilled create form
+  (front-runs the import below)
+- ICS file import (drag-and-drop) *(was v3.0, optional)*
+
+## Platform & launchers
+
+- ~~Home-screen widget~~ **shipped v2.5.0** — agenda + month widgets
+- ~~App shortcuts (launcher long-press → New event)~~ **shipped v2.5.0** —
+  optional quick-settings tile still open
+
+## Quality & reliability
+
+- **Accessibility pass** — TalkBack content descriptions across all screens,
+  dynamic-type / large-font reflow, touch-target audit. Quality bar for an
+  F-Droid app; nothing tracks it yet.
+- **Reminder delivery reliability** — exact alarms + battery-optimization
+  exemption; specced in the "Reminders — defaults & delivery reliability" slice
+  above (Tier 4 #9).
+
+## Locations & People *(go/no-go, captured 2026-06-11)*
+
+Beyond classic calendar-client scope; discussed, deliberately not planned
+in detail yet:
+
+- **Contact address picker** for the location field via the system picker
+  (`ACTION_PICK` on postal addresses) — one-shot, needs no READ_CONTACTS,
+  fits the privacy story. Same mechanism later for picking emails.
+- **OSM address autocomplete** in the location field (type "Brandenburger
+  Tor" → tap suggestion → resolved address inserted). Backend would be
+  Photon (Nominatim's public policy forbids autocomplete). **Requires the
+  INTERNET permission** — first dent in the "no network access" promise;
+  if built: opt-in (off by default), honest copy, configurable endpoint
+  for self-hosters, onboarding footnote + F-Droid copy reworded. This
+  trade-off is an explicit go/no-go decision before any work starts.
+- **Inline contact suggestions** while typing (needs READ_CONTACTS) — only
+  if the picker proves clunky.
+- **Attendee editing / invites from contacts** — own milestone; writing
+  `Attendees` rows touches sync-adapter invitation behavior (Google vs
+  DAVx5 differ).
+
+## Consciously rejected
+
+- Travel time / weather / smart suggestions (network, core-promise conflict)
+- Natural-language quick entry (high effort, locale-fragile; the prefilled
+  form already covers fast entry)
+- Quick-add sheet (the prefilled full form already covers it — cut in v2.0)

.planning/STATE.md

@@ -1,12 +1,17 @@
 # Calendula — Current State
 
-*Last updated: 2026-06-10*
+*Last updated: 2026-06-17*
 
 ## Status
 
-**Milestone:** v0.4 — Week view (in progress)
-**Phase:** Month + Week views implemented; cross-cutting wiring (detail sheet,
-filter, settings, jump-to-date) still stubbed
+**Milestone:** 2 (write support) **complete** — v2.0.0 shipped 2026-06-11;
+v2.1.0 (month event grid, drawer view tabs, cursor fix) shipped 2026-06-15.
+**Phase:** post-2.1 backlog work. v2.2.0 (tap-to-create in day/week + local
+calendar management) and v2.3.0 (Material 3 grouped-list redesign of Settings,
+the calendar manager and the navigation drawer) both shipped 2026-06-16;
+v2.4.0 (per-event colors) and v2.5.0 (jump-to-date, Agenda view, home-screen
+agenda + month widgets, and a "New event" launcher shortcut) shipped
+2026-06-17. The backlog is now organised by theme in `ROADMAP.md`.
 
 ## Progress
 
@@ -16,13 +21,110 @@ filter, settings, jump-to-date) still stubbed
 - [x] Plan 02 written and executed — data layer + permission flow + debug screen
 - [x] Month view (S1) — 6-week grid, event dots, today marker, swipe nav, three states (replaces debug screen)
 - [x] Week view (S2) — time schedule with overlap-resolved lanes, all-day strip, swipe nav, three states
-- [x] View-switcher (M1) wired — cycles Month ↔ Week (Day joins once S3 lands)
-- [ ] Day view (S3)
-- [ ] Event-detail sheet (S4) — week/month event taps are currently no-ops
-- [ ] Filter sheet (M3), Settings (M4), Jump-to-date (M2) — drawer entries stubbed
+- [x] Day view (S3) — single-column slice reusing the week layout
+- [x] View-switcher (M1) wired — cycles Month ↔ Week ↔ Day
+- [x] Event-detail screen (S4) — full-screen, humanized recurrence
+- [x] Filter sheet (M3) — per-calendar visibility, grouped by account, persisted, applied centrally in the repository
+- [x] Settings (M4) — appearance (theme, dynamic colour, week start), language (per-app locales), about
+- [~] Jump-to-date (M2) — **cut from scope**; "Today" half shipped in v0.5, date-picker dropped
+- [x] Full event read (v0.6) — reminders, status, availability, access level,
+  attendee role + self-response, foreign timezone, and linkified description
+  URLs in the detail view; new domain enums + mapper unit tests. (A dedicated
+  URL field was cut — no `CalendarContract` column backs it.)
+
+- [x] v1.1 write foundation — `WRITE_CALENDAR` (onboarding asks READ+WRITE,
+  only READ gates; contextual upgrade for v1.0 installs), read-only-calendar
+  detection (`CALENDAR_ACCESS_LEVEL` → `canModifyContents`, actions hidden for
+  WebCal/birthday calendars), delete from the detail screen (recurring:
+  "only this event" via cancelled exception / "all events in the series"),
+  repository + mapper tests
+
+- [x] v1.2 create event — full-screen `EventEditScreen` (title, all-day,
+  M3 date/time pickers with duration-preserving start moves, writable-only
+  calendar picker preselecting the last-used calendar, location, description),
+  "+" FAB on all three views prefilled with the visible day, `insertEvent`
+  with provider-correct all-day normalisation (UTC midnights, exclusive end),
+  domain/mapper/repository tests
+
+- [x] v1.3 edit event (shipped 2026-06-11) — `EventEditScreen` reused for
+  edit (detail-screen Edit action, `canModify`-gated, contextual WRITE
+  upgrade), dirty-checked partial `update` on the Events row (recurring:
+  series DTSTART moves by the user's delta, DURATION instead of DTEND),
+  reminder diff by minutes (kept rows keep their method), simple recurrence
+  picker (FREQ/INTERVAL/UNTIL/COUNT; complex RRULEs preserved verbatim and
+  shown humanized), `EventFormField.Recurrence` incl. settings default,
+  recurrence also available on create; domain/mapper/repository tests.
+  Review round 1: weekly BYDAY day-toggles in the custom picker ("every week
+  on Mon+Fri"). Review rounds 2–4: occurrence edit pulled forward from v2.0
+  and made three-way like delete ("this" = exception row via
+  `CONTENT_EXCEPTION_URI`, "this and following" = series split, "all" =
+  series update); delete equally three-way (truncation via RRULE UNTIL);
+  the edit-scope question moved to save time (Google model) — dirty
+  recurring saves park in `SaveUiState.AwaitingScope`, a changed rule drops
+  the "only this event" option
+
+- [x] v1.4 reminder notifications (shipped 2026-06-11) — exported
+  `EVENT_REMINDER` receiver → `CalendarAlerts` (SCHEDULED & due) →
+  dedicated channel, tap opens detail (singleTop deep link); best-effort
+  FIRED marking; one-time onboarding step requesting `POST_NOTIFICATIONS`
+  with duplicate-reminders warning; Settings mirror. Provider only fires
+  `METHOD_ALERT` rows (AOSP-verified), so email reminders never reach us
+
+- [x] v2.0 conflict dialog + store polish (shipped 2026-06-11 as v2.0.0) —
+  `EditSnapshot` compare on save (overwrite/discard; deleted → close),
+  quick-add cut, calendar-switch → v3 backlog; F-Droid/README copy
+  refreshed, fastlane screenshots DE+EN captured on-device
+
+- [x] v2.1 (shipped 2026-06-15) — month grid shows real events as
+  continuous multi-day bars; navigation-drawer View section
+  (Month/Week/Day); cursor-jump fix in event text fields
+
+- [x] v2.2 (shipped 2026-06-16) — tap an empty slot in day/week to create
+  (prefilled with that day + tapped hour, snapped to the hour); local
+  calendar management in a full-screen editor from Settings →
+  Calendars: create/rename/recolor/delete device-only calendars
+  (`ACCOUNT_TYPE_LOCAL`, sync-adapter insert) with name, pastel-previewed
+  colour, and description (stored in `CAL_SYNC1`); synced calendars listed
+  read-only grouped by account with a per-account "manage in source app"
+  deep-link (resolved from the account's authenticator: DAVx5/ICSx5/…) and
+  an add-account shortcut. Shared `InlineTextField` extracted to `ui.common`
+
+- [x] v2.3 settings/calendars/drawer redesign (shipped 2026-06-16) — adopted a
+  shared Material 3 grouped-list blueprint, modelled on the ReFra gallery app
+  and extracted to `ui/common/GroupedList.kt` (`CollapsingScaffold` with a
+  `LargeTopAppBar` exit-until-collapsed title; `GroupedRow` with Position-based
+  corner grouping, press-animated corners, `selected` + `minHeight` knobs).
+    - Settings: category hub (About card on top → version mark at the foot) with
+      sliding sub-pages (Appearance / New event form / Notifications); token-
+      based icon chips; theme/week-start/language pickers migrated from
+      `DropdownMenu` to OptionCard dialogs. New `ic_gitea.xml` (Simple Icons,
+      verbatim path) for the About "Source" button; en+de strings.
+    - Calendar manager: same collapsing scaffold + grouped rows; shared
+      `CalendarColorChip` (neutral chip, pastelised calendar glyph).
+    - Navigation drawer: branded header, grouped View switcher (active view
+      highlighted via `secondaryContainer`), the filter list restyled to
+      grouped rows with a trailing checkbox; the whole drawer scrolls as one.
+    - Cards use `surfaceContainerHigh` for readable contrast against `surface`.
+    - Donate button on the About card deferred (target still TBD).
+
+- [x] v2.4 per-event color (shipped 2026-06-17) — an optional "Color" field in
+  the event form. Read/render already resolved `EVENT_COLOR` with a calendar
+  fallback; this adds the write side and the picker. Palette-backed calendars
+  (Google, some CalDAV) pick from the account's `Colors` (`TYPE_EVENT`) and
+  write `EVENT_COLOR_KEY` so the color round-trips through sync; local
+  calendars write a raw `EVENT_COLOR` from the shared `CALENDAR_COLOR_PALETTE`
+  (extracted with the swatch row to `ui/common/ColorSwatchRow.kt`). Switching
+  calendars resets the choice (a key is account-scoped). A settings toggle
+  ("Allow colors on unsupported calendars", off by default) extends the raw
+  path to synced calendars with no palette, with an honest "may not survive
+  sync" warning on the picker and in Settings. Color writes flow through
+  insert / dirty-checked update / occurrence-exception; mapper + form tests.
 
 ## Next
 
-1. Day view (S3) — slot it into the view-switcher cycle
-2. Event-detail sheet (S4) — wire month-day and week-event taps to it
-3. Revisit month/week UI polish + shared anchor-date continuity across views
+1. Monitor the F-Droid build/publish for the v2.4.0 tag
+2. Decide the "Locations & People" and "remote calendar create/edit"
+   go/no-go calls (both hinge on the INTERNET permission) — see `ROADMAP.md`
+3. **Duplicate event** and **jump-to-date** are the cheap follow-ups; then
+   agenda view (strategic, backs a future widget). Full ranked sequence in
+   `ROADMAP.md` → "Near-term sequence".

CHANGELOG.md

@@ -7,6 +7,402 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [2.7.0] — 2026-06-18
+
+### Added
+- Share a single event as an `.ics` file from the event detail screen — hands a
+  standard calendar file to any app via the system share sheet.
+- Back up your local (device-only) calendars: Settings → Calendars → Export as
+  `.ics` file writes every event of your on-device calendars to a file you
+  choose. Local calendars aren't synced anywhere, so this is their only backup.
+- Open or share an `.ics` file into Calendula: a single event opens the create
+  form prefilled for review, while a file with many events (e.g. a backup) opens
+  a bulk import — pick a calendar and import them all. Re-importing a backup
+  won't create duplicates (events are matched by their unique identifier), and
+  anything Calendula can't represent (changed recurring occurrences, guest
+  lists) is reported rather than silently dropped.
+
+### Fixed
+- All-day events that cover a single day (e.g. a birthday) no longer show up on
+  the following day as well — in the day, week and month views or on the event
+  detail screen. The extra day came from interpreting the all-day date range in
+  the device's time zone instead of UTC.
+- Fixed the app crashing immediately on every launch in the optimized release
+  build: release code-shrinking (R8) was stripping a database class the
+  home-screen widget framework needs, so the app died at startup before showing
+  anything. Added the missing keep rule.
+
+## [2.6.0] — 2026-06-18
+
+### Added
+- App language can now be set from Android's system per-app language settings
+  (Android 13+), in addition to the in-app picker in Settings — and the app is
+  set up so further languages can be added by community translators
+
+### Fixed
+- Changing the app language in Settings now takes effect immediately; the
+  picker previously had no effect
+
+## [2.5.0] — 2026-06-17
+
+### Added
+- Home-screen widgets (two of them): an "Upcoming" agenda widget — a scrolling
+  list of the next month of events grouped under day headers, with refresh and
+  "New event" buttons — and a month-grid widget showing the full month with
+  today highlighted, connected multi-day event bars, and prev/next/today
+  navigation. Both reuse the in-app grouping and layout so they match the app
+  exactly, respect your hidden-calendar choices, and refresh automatically when
+  the calendar changes or the day rolls over. Tapping a day opens that day;
+  tapping an event opens its details
+- App shortcut: long-press the Calendula icon for a "New event" action that
+  jumps straight into the create-event form
+- Agenda view — a fourth top-level view alongside Month/Week/Day: a
+  forward-looking list of upcoming events grouped under "Today"/"Tomorrow"/date
+  headers, reachable from the view switcher
+- Jump to date — a "Jump to date" row in the navigation drawer opens a date
+  picker and moves the active view (Month/Week/Day/Agenda) to the chosen day
+
+## [2.4.0] — 2026-06-17
+
+### Added
+- Per-event colors: give a single event its own color, instead of always
+  inheriting its calendar's. Add the new "Color" field from "More fields" in
+  the event form. On calendars that publish their own color set — such as
+  Google — you pick from that calendar's palette, so the color is stored
+  with the event and shows correctly on every synced device. On local
+  calendars you pick from Calendula's palette. "Reset" returns an event to
+  its calendar's color
+- A new "Allow colors on unsupported calendars" setting (New event form,
+  off by default) extends per-event colors to calendars that publish no
+  color set of their own (some CalDAV). Such a color is kept on the device
+  and may be dropped or overwritten on that calendar's next sync — a
+  limitation of those calendars, called out plainly in the setting and on
+  the color picker
+
+## [2.3.0] — 2026-06-16
+
+### Changed
+- Redesigned Settings around the Material 3 grouped-list pattern: a large
+  title that collapses into the toolbar as you scroll, category cards on the
+  main screen, and dedicated sub-pages for Appearance, the new-event form, and
+  Notifications. The theme, week-start and language pickers now use the app's
+  standard option-card dialogs instead of dropdown menus
+- About moved to the top of Settings as a card — app icon, author, and quick
+  links to the source code and licence — with the version shown plainly at the
+  foot of the list
+- The Calendars screen now uses the same grouped-card layout and collapsing
+  title, and each calendar shows a soft pastel-tinted calendar glyph rather
+  than a plain colour swatch
+- Redesigned the navigation drawer to match: a branded header, the
+  Month / Week / Day switch and your calendars as grouped cards (with the
+  active view highlighted), and the whole drawer now scrolls as one
+
+## [2.2.0] — 2026-06-16
+
+### Added
+- Tap an empty slot in the day or week view to create an event there: the
+  create form opens prefilled with that day and the tapped hour (snapped to
+  the hour, one hour long). Tapping an existing event still opens it
+- Local calendars: create and manage device-only calendars that live
+  entirely on this phone — no account, no sync — from a new "Calendars"
+  screen in Settings. Give each a name, a colour, and an optional
+  description; rename, recolour, or delete them later. Useful when you want
+  a calendar without setting up an account
+- The Calendars screen also lists your synced calendars (DAVx5, ICSx5, …)
+  grouped by account, each with a "Manage" button that opens the app the
+  calendar actually comes from, plus an "Add account" shortcut to the
+  system account settings. Calendula never touches a synced calendar's
+  server itself — that stays with its own app
+
+### Changed
+- Colour swatches in the calendar editor now preview the soft, pastel tone
+  a calendar is actually drawn with, instead of a bright raw colour
+- The calendar editor reuses the event form's field and button styling for
+  a consistent look
+
+## [2.1.0] — 2026-06-15
+
+### Added
+- The month view now shows real events in each day instead of coloured
+  dots: all-day and multi-day events render as continuous bars at the top
+  (a multi-day event is one connected bar across the days it spans, not a
+  chip per day), with single-day timed events as filled pills beneath.
+  Up to three rows show per day, then a "+N" dot indicator for the rest.
+  Each day keeps a rounded surface background, matching the week and day
+  views; today is marked with a filled circle on its number
+- The slide-out panel now has a "View" section to switch between Month,
+  Week, and Day, mirroring the top-bar switcher pill — tapping a view
+  selects it and closes the drawer. The current view is highlighted
+
+### Fixed
+- Typing in the event title, location, and description fields no longer
+  makes the cursor jump around: the form state's round-trip to the UI was
+  hopping to a background dispatcher, so the text field saw a lagging value
+  while typing. Only the calendar/preferences reads stay off the main
+  thread now; the keystroke path is synchronous again
+
+## [2.0.0] — 2026-06-11
+
+### Added
+- Conflict handling when saving an edit: if the event changed elsewhere
+  (sync, another device) while the form was open, saving now asks whether
+  to keep or discard your changes instead of silently overwriting the
+  edited fields — and tells you when the event was deleted in the meantime.
+  "Keep" still writes only the fields you touched; external changes to
+  untouched fields survive either way
+- F-Droid store screenshots (German + English), captured with demo data
+
+### Changed
+- F-Droid description and README no longer claim the app is read-only —
+  they now describe write support and reminder delivery
+
+### Fixed
+- `versionName`/`versionCode` bumped to 2.0.0 / 13 — closing out the
+  write-support milestone (v1.1 through v2.0)
+
+## [1.4.0] — 2026-06-11
+
+### Added
+- Reminder notifications (v1.4): Calendula now delivers event reminders as
+  notifications itself — the system schedules them but posts nothing, so a
+  calendar app must (essential when Calendula is the only one installed).
+  Due reminders appear on a dedicated "Event reminders" channel; tapping one
+  opens the event's detail screen. Email reminders are never posted (the
+  provider only schedules alert-type reminders)
+- A one-time onboarding step after the calendar grant introduces reminders,
+  requests the notification permission (Android 13+), and warns that a second
+  calendar app with notifications on will duplicate them. "Not now" leaves
+  the feature off
+- Settings gained a "Notifications" section mirroring the choice: an event-
+  reminders toggle (default on) with the duplicate-reminders hint; turning it
+  on re-requests the notification permission when missing
+
+### Fixed
+- `versionName`/`versionCode` bumped to 1.4.0 / 12
+
+## [1.3.0] — 2026-06-11
+
+### Added
+- Event editing: a pencil action on the detail screen (writable calendars
+  only) opens the event form prefilled with the event. Only fields you
+  actually changed are written back; saving an untouched form is a no-op.
+  Sections holding data are always shown, regardless of the form-field
+  defaults; the calendar itself can't be changed while editing
+- Recurring events — scoped writes, chosen when saving (Google model):
+  "only this event" (a modified-occurrence exception), "this and all
+  following" (the series is split at the occurrence), or "all events in
+  the series". Changing the recurrence rule rules out "only this event"
+- Deleting a recurring event gained the middle option too: "this and all
+  following events" ends the series just before the chosen occurrence
+- Recurrence picker (create and edit): one-tap daily/weekly/monthly/yearly
+  presets plus a custom step with interval + unit, weekday toggles for
+  weekly rules ("every week on Mon and Fri"), and an end condition (never /
+  on a date / after a number of times). Rules the picker can't express
+  (e.g. "second Thursday monthly") are shown humanized and preserved
+  verbatim unless replaced. Recurrence also joined the optional form
+  fields and their settings defaults
+- Validation: a repeat that would end before the event starts is flagged
+  (it would otherwise vanish from every view)
+
+### Changed
+- Editing reminders reconciles against the provider's actual rows:
+  reminders you didn't touch keep their method (e.g. email reminders on
+  synced events survive unrelated edits)
+- The contextual WRITE_CALENDAR upgrade for v1.0 installs covers the edit
+  action like delete
+
+### Fixed
+- Splitting a series ("this and following") sends the complete time-column
+  set in one update, so the provider regenerates its cached instances — an
+  RRULE-only update left a stale duplicate of the tapped occurrence on the
+  split day
+- RRULE UNTIL values are written as the local end of day expressed in UTC
+  (instead of a flat `T235959Z`), so recurrences can't leak an extra day in
+  timezones ahead of UTC
+- `versionName`/`versionCode` bumped to 1.3.0 / 11
+
+## [1.2.1] — 2026-06-11
+
+### Added
+- Optional event-form fields with user-controlled defaults: reminders,
+  availability (busy/free), and visibility (default/public/private/
+  confidential) joined location and description as form sections. Settings
+  gained a "New event form" section choosing which show by default; the rest
+  unfold via a "More fields" picker
+- Reminders editor: stacked rows with right-bound remove, full-width add
+  action; the picker offers one-tap presets and a custom amount + unit
+  (minutes/hours/days/weeks) step
+- `OptionCard` — the app's standard selection-dialog row (full-width tonal
+  card, optional icon + supporting line, highlighted selection). All dialogs
+  (calendar, visibility, more-fields, reminder presets, recurring-delete)
+  now use it; radio-row dialogs are retired
+
+### Changed
+- Event form redesigned onto the detail screen's design system: tonal cards
+  with gutter icons (top-aligned on tall cards), borderless inline text
+  fields, calendar-coloured accent bar under the title, no dividers, no
+  top-bar title; placeholders render clearly fainter than input
+- M3 Expressive motion: the theme now provides a MotionScheme
+  (`MaterialExpressiveTheme`, standard springs — expressive bounce reviewed
+  as overdone), the FAB stack and "more fields" reveals animate on theme
+  springs
+- The jump-to-today slide is direction-aware (future → today slides in from
+  the left, past → from the right)
+- `versionName`/`versionCode` bumped to 1.2.1 / 10
+
+### Fixed
+- The keyboard no longer pans the whole event form; the screen stays
+  anchored and the focused field scrolls into view (`adjustResize` +
+  `imePadding`)
+
+## [1.2.0] — 2026-06-11
+
+### Added
+- Create events (milestone 2, slice 2):
+  - A "+" FAB on the month, week, and day views opens a new full-screen event
+    form, prefilled with the visible day (today at the next full hour, or
+    09:00 on other days)
+  - The form covers title, all-day toggle, start/end with Material 3 date and
+    time pickers (moving the start drags the end along, preserving duration),
+    target calendar, location, and description
+  - The calendar picker offers only writable calendars and preselects the one
+    you last created an event in
+  - Validation on save ("ends before it starts", no writable calendar), with
+    the same contextual write-permission upgrade as delete
+  - All-day events are stored provider-correctly (UTC midnights, exclusive
+    end), timed events in the device time zone
+
+### Changed
+- The jump-to-today pill now stacks above the new "+" FAB instead of being
+  the only floating action
+- `versionName`/`versionCode` bumped to 1.2.0 / 9
+
+## [1.1.0] — 2026-06-11
+
+### Added
+- Write foundation (milestone 2, slice 1): Calendula can now **delete events**.
+  - Delete action on the event detail screen, with a confirmation dialog;
+    recurring events choose between "Only this event" (a cancelled exception,
+    so the rest of the series survives) and "All events in the series"
+  - `WRITE_CALENDAR` permission: onboarding asks for read+write in one system
+    dialog, but only read access is required — declining write keeps the app
+    fully usable read-only. Existing v1.0 installs are asked for the write
+    upgrade in place, on their first delete
+  - Read-only calendars (WebCal subscriptions, birthday calendars, …) are
+    detected via `CALENDAR_ACCESS_LEVEL` and show no edit/delete actions at all
+
+### Changed
+- Onboarding copy no longer claims "read-only"; it now says your data stays on
+  the device (still no internet permission, still zero telemetry)
+- The placeholder Edit button on the detail screen (a no-op since v0.4) is
+  removed until editing ships in a later slice
+- `versionName`/`versionCode` bumped to 1.1.0 / 8
+
+## [1.0.0] — 2026-06-11
+
+First public release. Calendula is a read-only, Material 3 Expressive calendar
+that lives entirely on top of Android's `CalendarContract` — every calendar
+synced to the device (CalDAV via DAVx5, Google, local, WebCal, …) shows up
+automatically, with zero telemetry and no internet permission.
+
+### Highlights (accumulated across v0.1 → v0.6)
+- Month, week, and day views with a view switcher, swipe navigation, and
+  Loading / Failure / Success states on every screen
+- Full-screen event detail surfacing every readable `CalendarContract` field —
+  times, recurrence (humanised), location, description (with tappable links),
+  attendees + roles + your own response, reminders, status, availability,
+  access level, and foreign time zones
+- Per-calendar visibility filter (grouped by account, persisted) and a Settings
+  screen (theme, Material You dynamic colour, week start, app language)
+- Material 3 Expressive first-run onboarding for calendar access
+- German + English localization throughout
+
+### Changed
+- `versionName`/`versionCode` bumped to 1.0.0 / 7
+
+## [0.6.0] — 2026-06-11
+
+### Added
+- Full event read (v0.6): the detail screen now surfaces every readable
+  `CalendarContract` field that V1 had been dropping —
+  - **Reminders** — each configured lead time, humanised ("10 minutes before",
+    "1 day before", "At time of event"), read from `CalendarContract.Reminders`
+  - **Status** — Tentative / Cancelled chip under the title; a cancelled event
+    also strikes through its title (Confirmed shows no chip)
+  - **Availability** — a "Free" pill pinned top-right of the title when the
+    event doesn't block your time (`Events.AVAILABILITY`, the iCal TRANSP
+    field); the default "Busy" is left implicit to avoid noise on every event
+  - **Access level** — a Private / Confidential chip when the event isn't public
+  - **Attendee role** — organizer / optional / resource badge under each
+    attendee, plus the device user's own response ("Your response: …") from
+    `Events.SELF_ATTENDEE_STATUS`
+  - **Time zone** — shown only for timed events pinned to a zone other than the
+    device's, so cross-zone events read unambiguously
+  - **Linked URLs** — http(s) links in the description are now tappable
+- Domain model rounded out with `Reminder`, `EventStatus`, `Availability`,
+  `AccessLevel`, `AttendeeRelationship`, `AttendeeType`, and the attendee/self
+  status fields; mappers + unit tests cover every new column's integer codes
+
+### Changed
+- Redesigned the first-run grant-access screen — the onboarding a new user
+  sees. Material 3 Expressive layout: branded launcher-mark hero, an app-name
+  eyebrow, a benefit-led headline, three trust rows (on-device, every calendar,
+  no tracking) with tonal icon chips, a full-width filled CTA with a trailing
+  arrow, and a "Read-only · no internet permission" footnote (the app declares
+  only `READ_CALENDAR`). The denied/recovery state shares the same shell with a
+  lock-badged hero and Open-settings / Try-again actions
+- `versionName`/`versionCode` bumped to 0.6.0 / 6
+
+### Notes
+- A dedicated event **URL** field was dropped from scope: `CalendarContract`
+  has no `Events.URL` column (only `CUSTOM_APP_URI`, an app deep-link), so URLs
+  are surfaced by linkifying the description instead
+
+## [0.5.0] — 2026-06-10
+
+### Added
+- Calendar filter (M3): the navigation drawer now hosts the calendar list
+  inline — every calendar grouped by account, each with a colour swatch and a
+  visibility switch. Hiding a calendar is persisted app-side (DataStore,
+  separate from the system VISIBLE flag) and applied centrally in the
+  repository, so month/week/day re-filter live the moment a switch flips.
+  The drawer was trimmed to just Today, the calendar filter, and Settings
+  (the stubbed jump-to-date entry was removed; jump-to-date was later cut
+  from scope entirely)
+- Settings (M4): a full-screen destination with
+  - **Appearance** — theme (System / Light / Dark), Material You dynamic colour
+    (auto-disabled below Android 12), week start (Automatic / Monday / Sunday)
+  - **Language** — app language (System / Deutsch / English) via per-app
+    locales, persisted across cold starts down to Android 10
+  - **About** — version, license, and a link to the source on Gitea
+- Week-start preference now drives the month grid and week view; "Automatic"
+  follows the active locale (Monday in DE, Sunday in en-US)
+
+### Changed
+- Theme is driven by one activity-scoped settings source, so a theme or
+  dynamic-colour change applies app-wide immediately
+- `versionName`/`versionCode` bumped to 0.5.0 / 5 (the in-repo version had
+  lagged behind the release tags); the About screen reads it directly
+
+## [0.4.0] — 2026-06-10
+
+### Added
+- Event detail (S4): full-screen destination (MD3 list→detail, not a bottom
+  sheet) opened by tapping an event in the week/day timeline — title with a
+  calendar-colour accent line, a card per field (when, calendar, location,
+  description, attendees, recurrence) with leading icons, location tap opens a
+  maps intent, Loading/Failure/Success states, slide-in/out over the calendar
+- Human-readable recurrence: RRULE rendered as e.g. "Every week on _Tue_ and
+  _Thu_ until 31 Dec 2026" (FREQ/INTERVAL/BYDAY/UNTIL/COUNT, abbreviated +
+  italicised day names, localized list formatting), with a generic fallback
+- Month → day navigation: tapping a day cell opens the day view on that date
+
+### Fixed
+- Recurring events failed to open in the detail view: the series row stores
+  DURATION instead of DTEND, so the mapper dropped it (EventNotFound). The
+  detail now keeps such events and shows the tapped occurrence's own times
+  (from CalendarContract.Instances) instead of the series start
+
 ## [0.3.0] — 2026-06-10
 
 ### Added

README.md

@@ -1,43 +1,120 @@
-# Calendula
+<div align="center">
 
-A modern Material 3 Expressive calendar app for Android.
+<img src="fdroid-metadata/de.jeanlucmakiola.calendula/en-US/icon.png" width="112" alt="Calendula icon">
 
-Calendula is named after the flower of the same name, whose name comes from
-the Latin *kalendae* — the first day of the month — the same root as the
-word "calendar". Calendula reads from Android's built-in `CalendarContract`,
-so any calendar source synced to your device (CalDAV via DAVx5, Google,
-local, WebCal subscriptions, ...) is shown.
+<h1>Calendula</h1>
 
-## Features (V1)
+<p><strong>A modern Material 3 Expressive calendar for Android.</strong><br>
+Reads, writes, and reminds — on top of the system calendar, with zero network access.</p>
 
-- Month, Week, and Day views
-- Read-only event details (write support comes in V2)
-- Multi-calendar visibility toggle
-- Material You Dynamic Color (Android 12+)
-- Light/Dark theme follows system
-- German + English UI
+<p>
+<a href="https://gitea.jeanlucmakiola.de/makiolaj/calendula/actions"><img src="https://gitea.jeanlucmakiola.de/makiolaj/calendula/actions/workflows/ci.yaml/badge.svg?branch=main" alt="CI"></a>
+<img src="https://img.shields.io/badge/Android-10%2B-3DDC84?logo=android&logoColor=white" alt="Android 10+">
+<img src="https://img.shields.io/badge/Kotlin-Compose-7F52FF?logo=kotlin&logoColor=white" alt="Kotlin + Compose">
+<img src="https://img.shields.io/badge/Material%203-Expressive-4285F4" alt="Material 3 Expressive">
+<a href="LICENSE"><img src="https://img.shields.io/badge/License-MIT-green" alt="MIT License"></a>
+</p>
 
-## Building
+<p>
+<img src="fdroid-metadata/de.jeanlucmakiola.calendula/en-US/phoneScreenshots/01-week.png" width="19%" alt="Week view">&nbsp;
+<img src="fdroid-metadata/de.jeanlucmakiola.calendula/en-US/phoneScreenshots/02-month.png" width="19%" alt="Month view">&nbsp;
+<img src="fdroid-metadata/de.jeanlucmakiola.calendula/en-US/phoneScreenshots/04-detail.png" width="19%" alt="Event detail">&nbsp;
+<img src="fdroid-metadata/de.jeanlucmakiola.calendula/en-US/phoneScreenshots/05-edit.png" width="19%" alt="Event form">&nbsp;
+<img src="fdroid-metadata/de.jeanlucmakiola.calendula/en-US/phoneScreenshots/06-onboarding.png" width="19%" alt="Reminder onboarding">
+</p>
 
-Requires Android SDK 36 and JDK 17. The Gradle wrapper is checked in, so no host Gradle install is needed:
+</div>
 
-```bash
-# Build debug APK
-./gradlew assembleDebug
+Calendula is named after the flower whose name — like the word *calendar* —
+comes from the Latin *kalendae*, the first day of the month. It lives
+entirely on top of Android's `CalendarContract`: any calendar synced to your
+device (CalDAV via DAVx5, Google, local, WebCal subscriptions, …) simply
+appears, and everything you create or edit syncs back the same way. No own
+database, no sync stack reinvented.
 
-# Run unit tests
-./gradlew test
+## ✨ Features
 
-# Run lint
-./gradlew lint
+**Calendar**
+
+- Month, week, and day views with a one-tap view switcher
+- Full event details — attendees and their responses, reminders, recurrence
+  (humanized), availability, visibility, foreign time zones
+- Per-calendar visibility toggle, grouped by account
+
+**Editing**
+
+- Create, edit, and delete events — including recurring events with scoped
+  writes: *only this event*, *this and all following*, or *the whole series*
+- Recurrence picker with one-tap presets and custom rules (interval, weekday
+  toggles, end conditions); rules it can't express are preserved verbatim
+- Conflict-safe saves: if an event changed elsewhere while you were editing,
+  Calendula asks instead of silently overwriting
+- Read-only calendars (WebCal, birthdays) are detected and respected
+
+**Reminders**
+
+- Event reminders delivered by Calendula itself as notifications —
+  essential when it's your only calendar app, since Android delegates
+  reminder delivery to calendar apps
+- Tap a reminder to land on the event
+
+**Design & privacy**
+
+- Real Material 3 Expressive throughout — dynamic color (Android 12+),
+  expressive motion and shapes, light/dark theme
+- German and English UI, per-app language setting
+- **Zero telemetry, zero analytics, no internet permission** — your data
+  never leaves the device
+
+## 📦 Install
+
+Calendula ships through a self-hosted F-Droid repository; every version tag
+is built, signed, and published there automatically.
+
+1. Install an F-Droid client ([F-Droid](https://f-droid.org), Droid-ify, Neo
+   Store, …).
+2. Add the repository — open this link on your phone, or paste it under
+   *Settings → Repositories → Add*:
+
+   ```
+   https://apps.dev.jeanlucmakiola.de/dev/fdroid/repo?fingerprint=C2C0640402BF458FC0ED957AF0B37AA4C14022E72F89CE90B5965B458CF73425
    ```
 
-If your default JDK is something other than 17, set `JAVA_HOME` explicitly:
+   <sub>Repo: `https://apps.dev.jeanlucmakiola.de/dev/fdroid/repo` ·
+   fingerprint (SHA-256):
+   `C2C0 6404 02BF 458F C0ED 957A F0B3 7AA4 C140 22E7 2F89 CE90 B596 5B45 8CF7 3425`</sub>
+
+3. Refresh, search for **Calendula**, install. Updates arrive like any
+   other F-Droid app.
+
+Alternatively, build from source — see below.
+
+## 🛠 Building
+
+Requires Android SDK 36+ and JDK 17. The Gradle wrapper is checked in:
 
 ```bash
-JAVA_HOME=/path/to/jdk-17 ./gradlew assembleDebug
+./gradlew assembleDebug   # debug APK
+./gradlew test            # JVM unit tests
+./gradlew lint            # Android lint
 ```
 
-## License
+If your default JDK is not 17, set `JAVA_HOME` explicitly.
+
+## 🏗 Architecture
+
+Single-activity Compose app, layered `UI → Repository → DataSource →
+CalendarContract`, observer-driven refresh, JVM-first tests. The full tour —
+including the recurring-write and reminder pipelines — lives in
+[docs/ARCHITECTURE.md](docs/ARCHITECTURE.md).
+
+## 🗺 Roadmap
+
+Shipped: read (v1.0), write (v1.1–v2.0), reminder delivery (v1.4).
+Next up: power-user features — widget, search, tablet layouts. The living
+roadmap is in [.planning/ROADMAP.md](.planning/ROADMAP.md), the release
+history in [CHANGELOG.md](CHANGELOG.md).
+
+## 📜 License
 
 [MIT](LICENSE) — Jean-Luc Makiola, 2026

app/build.gradle.kts

@@ -23,8 +23,13 @@ android {
         applicationId = "de.jeanlucmakiola.calendula"
         minSdk = 29
         targetSdk = 36
-        versionCode = 1
-        versionName = "0.1.0"
+        // The git tag is the single source of truth for released builds: at
+        // release time .gitea/workflows/release.yaml derives both fields from
+        // the tag, with versionCode = MAJOR*10000 + MINOR*100 + PATCH
+        // (e.g. v2.0.0 -> 20000). These committed values are the dev/local
+        // default; keep them matching the latest released tag. See docs/RELEASING.md.
+        versionCode = 20700
+        versionName = "2.7.0"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }
@@ -73,6 +78,15 @@ android {
         }
     }
 
+    lint {
+        // Community translations are expected to be partial — a missing string
+        // falls back to the English base at runtime — so don't fail the build on
+        // it. Stale/extra keys (ExtraTranslation) stay fatal; scripts/
+        // check_translations.py guards the same invariants with clearer,
+        // translator-facing messages.
+        informational += "MissingTranslation"
+    }
+
     testOptions {
         unitTests {
             all { it.useJUnitPlatform() }
@@ -89,6 +103,7 @@ kotlin {
 
 dependencies {
     implementation(libs.androidx.core.ktx)
+    implementation(libs.androidx.appcompat)
     implementation(libs.androidx.lifecycle.runtime.ktx)
     implementation(libs.androidx.lifecycle.runtime.compose)
     implementation(libs.androidx.activity.compose)
@@ -99,6 +114,7 @@ dependencies {
     implementation(libs.androidx.ui.tooling.preview)
     implementation(libs.androidx.material3)
     implementation(libs.androidx.compose.material.icons.core)
+    implementation(libs.androidx.compose.material.icons.extended)
 
     implementation(libs.hilt.android)
     implementation(libs.androidx.hilt.navigation.compose)
@@ -106,6 +122,9 @@ dependencies {
 
     implementation(libs.androidx.datastore.preferences)
 
+    implementation(libs.androidx.glance.appwidget)
+    implementation(libs.androidx.glance.material3)
+
     implementation(libs.kotlinx.datetime)
     implementation(libs.kotlinx.coroutines.core)
 

app/proguard-rules.pro

@@ -4,3 +4,14 @@
 
 # Compose Compiler may keep its own; defaults are fine
 -dontwarn org.jetbrains.annotations.**
+
+# Room database implementations (pulled in transitively via
+# androidx.glance:glance-appwidget → androidx.work → androidx.room).
+# The widgets rely on Glance, whose WorkManager backend stores state in a Room
+# database. Under R8 full mode (AGP 9 default) the generated *_Impl subclasses
+# of RoomDatabase lose their usable no-arg constructor / are marked abstract,
+# so Room's reflective instantiation throws InstantiationException and the app
+# crashes at startup with "Failed to create an instance of ...WorkDatabase".
+# Keep the generated Room database implementations fully intact.
+-keep class * extends androidx.room.RoomDatabase { *; }
+-dontwarn androidx.room.paging.**

app/src/androidTest/java/de/jeanlucmakiola/calendula/data/calendar/CalendarRepositorySmokeTest.kt

@@ -1,10 +1,14 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
 import android.Manifest
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.PreferenceDataStoreFactory
+import androidx.datastore.preferences.core.Preferences
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import androidx.test.platform.app.InstrumentationRegistry
 import androidx.test.rule.GrantPermissionRule
 import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.runBlocking
@@ -24,7 +28,10 @@ class CalendarRepositorySmokeTest {
 
     private fun newRepo(): CalendarRepositoryImpl {
         val dataSource = AndroidCalendarDataSource(context)
-        return CalendarRepositoryImpl(dataSource, Dispatchers.IO)
+        val store: DataStore<Preferences> = PreferenceDataStoreFactory.create(
+            produceFile = { context.cacheDir.resolve("smoke_test_prefs.preferences_pb") },
+        )
+        return CalendarRepositoryImpl(dataSource, CalendarPrefs(store), Dispatchers.IO)
     }
 
     @Test

app/src/main/AndroidManifest.xml

@@ -3,6 +3,27 @@
     xmlns:tools="http://schemas.android.com/tools">
 
     <uses-permission android:name="android.permission.READ_CALENDAR" />
+    <uses-permission android:name="android.permission.WRITE_CALENDAR" />
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
+    <!--
+      Lets the "Reliable delivery" setting open the direct system dialog to
+      exempt Calendula from battery optimisation (so reminder broadcasts aren't
+      delayed by Doze). Used only to launch that dialog; falls back to the
+      battery-optimisation list if the OS declines the direct intent.
+    -->
+    <uses-permission android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS" />
+
+    <!-- Package visibility (Android 11+): without this, getLaunchIntentForPackage
+         returns null and the calendar manager's per-account "manage" button can't
+         open the source sync app (DAVx5, ICSx5, Google Calendar, …). The LAUNCHER
+         intent makes launchable apps visible so we can launch whichever app owns a
+         calendar account's authenticator. -->
+    <queries>
+        <intent>
+            <action android:name="android.intent.action.MAIN" />
+            <category android:name="android.intent.category.LAUNCHER" />
+        </intent>
+    </queries>
 
     <application
         android:name=".CalendulaApp"
@@ -11,18 +32,124 @@
         android:fullBackupContent="@xml/backup_rules"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
+        android:localeConfig="@xml/locales_config"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/Theme.Calendula"
         tools:targetApi="35">
         <activity
             android:name=".MainActivity"
-            android:exported="true">
+            android:exported="true"
+            android:launchMode="singleTop"
+            android:windowSoftInputMode="adjustResize">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+
+            <!-- Open a .ics file (file manager / email attachment / browser). -->
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.BROWSABLE" />
+                <data android:scheme="content" android:mimeType="text/calendar" />
+                <data android:scheme="file" android:mimeType="text/calendar" />
+            </intent-filter>
+            <!-- Receive a .ics shared from another app. -->
+            <intent-filter>
+                <action android:name="android.intent.action.SEND" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="text/calendar" />
+            </intent-filter>
+
+            <!-- Launcher long-press shortcuts (e.g. "New event"). -->
+            <meta-data
+                android:name="android.app.shortcuts"
+                android:resource="@xml/shortcuts" />
         </activity>
+
+        <!-- The provider broadcasts EVENT_REMINDER at reminder time but posts
+             no notification itself — a calendar app must (v1.4, Etar model).
+             Exported: the broadcast arrives from the provider's process. -->
+        <receiver
+            android:name=".data.reminders.EventReminderReceiver"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.EVENT_REMINDER" />
+                <data
+                    android:host="com.android.calendar"
+                    android:scheme="content" />
+            </intent-filter>
+        </receiver>
+
+        <!-- Home-screen widgets (Glance). Exported: the launcher/host binds them. -->
+        <receiver
+            android:name=".widget.agenda.AgendaWidgetReceiver"
+            android:label="@string/widget_agenda_label"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/appwidget_info_agenda" />
+        </receiver>
+
+        <receiver
+            android:name=".widget.month.MonthWidgetReceiver"
+            android:label="@string/widget_month_label"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
+            </intent-filter>
+            <meta-data
+                android:name="android.appwidget.provider"
+                android:resource="@xml/appwidget_info_month" />
+        </receiver>
+
+        <!-- Keeps both widgets fresh: the calendar provider broadcasts
+             PROVIDER_CHANGED on any data change (our writes and external sync),
+             and the system broadcasts the date/time ones at midnight / clock
+             changes so "today" highlighting rolls over. -->
+        <receiver
+            android:name=".widget.WidgetUpdateReceiver"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.PROVIDER_CHANGED" />
+                <data
+                    android:host="com.android.calendar"
+                    android:scheme="content" />
+            </intent-filter>
+            <intent-filter>
+                <action android:name="android.intent.action.DATE_CHANGED" />
+                <action android:name="android.intent.action.TIME_SET" />
+                <action android:name="android.intent.action.TIMEZONE_CHANGED" />
+            </intent-filter>
+        </receiver>
+
+        <!-- Hands .ics files we stage in the cache to other apps via a content
+             Uri (single-event share). Authority tracks applicationId so the
+             debug suffix doesn't break getUriForFile. -->
+        <provider
+            android:name="androidx.core.content.FileProvider"
+            android:authorities="${applicationId}.fileprovider"
+            android:exported="false"
+            android:grantUriPermissions="true">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/file_paths" />
+        </provider>
+
+        <!-- Persists the per-app language (M4) on API < 33, where the platform
+             per-app-languages API is unavailable. On 33+ this is a no-op. -->
+        <service
+            android:name="androidx.appcompat.app.AppLocalesMetadataHolderService"
+            android:enabled="false"
+            android:exported="false">
+            <meta-data
+                android:name="autoStoreLocales"
+                android:value="true" />
+        </service>
     </application>
 
 </manifest>

app/src/main/java/de/jeanlucmakiola/calendula/MainActivity.kt

@@ -1,24 +1,165 @@
 package de.jeanlucmakiola.calendula
 
+import android.content.Context
+import android.content.Intent
+import android.net.Uri
 import android.os.Bundle
-import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
+import androidx.appcompat.app.AppCompatActivity
+import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
+import androidx.core.content.IntentCompat
+import androidx.core.net.toUri
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import dagger.hilt.android.AndroidEntryPoint
+import de.jeanlucmakiola.calendula.data.prefs.ThemeMode
 import de.jeanlucmakiola.calendula.ui.RootScreen
+import de.jeanlucmakiola.calendula.ui.WidgetNavRequest
+import de.jeanlucmakiola.calendula.ui.settings.SettingsViewModel
 import de.jeanlucmakiola.calendula.ui.theme.CalendulaTheme
+import kotlinx.datetime.LocalDate
 
 @AndroidEntryPoint
-class MainActivity : ComponentActivity() {
+class MainActivity : AppCompatActivity() {
+
+    // The occurrence a reminder notification was tapped for (eventId, begin,
+    // end — the detail screen's key shape). singleTop + onNewIntent route a
+    // tap into the running activity; CalendarHost consumes and clears it.
+    private var requestedDetailKey by mutableStateOf<LongArray?>(null)
+
+    // A navigation a home-screen widget asked for (open a date / start a
+    // create). Consumed once by CalendarHost, same pattern as the detail key.
+    private var requestedNav by mutableStateOf<WidgetNavRequest?>(null)
+
+    // An .ics file opened/shared into the app (ACTION_VIEW/SEND). Consumed once
+    // by CalendarHost's import flow.
+    private var requestedImportUri by mutableStateOf<Uri?>(null)
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         enableEdgeToEdge()
+        requestedDetailKey = intent.detailKeyOrNull()
+        requestedNav = intent.navRequestOrNull()
+        requestedImportUri = intent.importUriOrNull()
         setContent {
-            CalendulaTheme {
-                RootScreen(modifier = Modifier.fillMaxSize())
+            // One activity-scoped SettingsViewModel drives both the theme here
+            // and the Settings screen, so a theme change applies app-wide at once.
+            val settingsViewModel: SettingsViewModel = hiltViewModel()
+            val settings by settingsViewModel.state.collectAsStateWithLifecycle()
+            val darkTheme = when (settings.themeMode) {
+                ThemeMode.SYSTEM -> isSystemInDarkTheme()
+                ThemeMode.LIGHT -> false
+                ThemeMode.DARK -> true
+            }
+            CalendulaTheme(
+                darkTheme = darkTheme,
+                dynamicColor = settings.dynamicColor,
+            ) {
+                RootScreen(
+                    modifier = Modifier.fillMaxSize(),
+                    requestedDetailKey = requestedDetailKey,
+                    onDetailKeyConsumed = { requestedDetailKey = null },
+                    widgetNavRequest = requestedNav,
+                    onWidgetNavConsumed = { requestedNav = null },
+                    requestedImportUri = requestedImportUri,
+                    onImportConsumed = { requestedImportUri = null },
+                )
             }
         }
     }
+
+    override fun onNewIntent(intent: Intent) {
+        super.onNewIntent(intent)
+        intent.detailKeyOrNull()?.let { requestedDetailKey = it }
+        intent.navRequestOrNull()?.let { requestedNav = it }
+        intent.importUriOrNull()?.let { requestedImportUri = it }
+    }
+
+    /**
+     * The `.ics` Uri an external app asked us to open (file manager `ACTION_VIEW`)
+     * or share into us (`ACTION_SEND`). Restricted to content/file schemes so the
+     * app's own `calendula://` deep-links never match.
+     */
+    private fun Intent.importUriOrNull(): Uri? {
+        val uri = when (action) {
+            Intent.ACTION_VIEW -> data
+            Intent.ACTION_SEND -> IntentCompat.getParcelableExtra(this, Intent.EXTRA_STREAM, Uri::class.java)
+            else -> null
+        } ?: return null
+        return uri.takeIf { it.scheme == "content" || it.scheme == "file" }
+    }
+
+    private fun Intent.navRequestOrNull(): WidgetNavRequest? = when {
+        // Launcher long-press "New event" shortcut. Static shortcut intents
+        // can't carry typed extras, so the action alone signals create-on-today.
+        action == ACTION_NEW_EVENT -> WidgetNavRequest.Create(null)
+        getBooleanExtra(EXTRA_CREATE, false) ->
+            WidgetNavRequest.Create(getStringExtra(EXTRA_DATE_ISO))
+        getStringExtra(EXTRA_DATE_ISO) != null ->
+            WidgetNavRequest.OpenDate(getStringExtra(EXTRA_DATE_ISO)!!)
+        else -> null
+    }
+
+    private fun Intent.detailKeyOrNull(): LongArray? {
+        val eventId = getLongExtra(EXTRA_EVENT_ID, -1L)
+        if (eventId == -1L) return null
+        return longArrayOf(
+            eventId,
+            getLongExtra(EXTRA_BEGIN_MILLIS, 0L),
+            getLongExtra(EXTRA_END_MILLIS, 0L),
+        )
+    }
+
+    companion object {
+        private const val EXTRA_EVENT_ID = "de.jeanlucmakiola.calendula.extra.EVENT_ID"
+        private const val EXTRA_BEGIN_MILLIS = "de.jeanlucmakiola.calendula.extra.BEGIN"
+        private const val EXTRA_END_MILLIS = "de.jeanlucmakiola.calendula.extra.END"
+        private const val EXTRA_DATE_ISO = "de.jeanlucmakiola.calendula.extra.DATE_ISO"
+        private const val EXTRA_CREATE = "de.jeanlucmakiola.calendula.extra.CREATE"
+
+        // Fired by the launcher long-press "New event" shortcut (res/xml/
+        // shortcuts.xml hardcodes this string — keep the two in sync).
+        const val ACTION_NEW_EVENT = "de.jeanlucmakiola.calendula.action.NEW_EVENT"
+
+        /**
+         * Intent opening the detail screen of one occurrence (reminder
+         * notifications). The synthetic data URI keys the intent so
+         * PendingIntents for different occurrences never collapse into one.
+         */
+        fun eventDetailIntent(
+            context: Context,
+            eventId: Long,
+            beginMillis: Long,
+            endMillis: Long,
+        ): Intent = Intent(context, MainActivity::class.java).apply {
+            data = "calendula://event/$eventId/$beginMillis".toUri()
+            putExtra(EXTRA_EVENT_ID, eventId)
+            putExtra(EXTRA_BEGIN_MILLIS, beginMillis)
+            putExtra(EXTRA_END_MILLIS, endMillis)
+            addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+        }
+
+        /** Open the day view anchored on [date] (home-screen widgets). */
+        fun openDateIntent(context: Context, date: LocalDate): Intent =
+            Intent(context, MainActivity::class.java).apply {
+                data = "calendula://date/$date".toUri()
+                putExtra(EXTRA_DATE_ISO, date.toString())
+                addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+            }
+
+        /** Open the create-event form prefilled for [date] (home-screen widgets). */
+        fun openCreateIntent(context: Context, date: LocalDate): Intent =
+            Intent(context, MainActivity::class.java).apply {
+                data = "calendula://create/$date".toUri()
+                putExtra(EXTRA_CREATE, true)
+                putExtra(EXTRA_DATE_ISO, date.toString())
+                addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+            }
+    }
 }

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/AllDayReminderEncoding.kt

@@ -0,0 +1,70 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import java.time.Instant
+import java.time.LocalDate
+import java.time.LocalTime
+import java.time.ZoneId
+import java.time.ZoneOffset
+import java.time.temporal.ChronoUnit
+
+/**
+ * Translates an all-day reminder between the **semantic** lead time the UI
+ * speaks (whole days before the event — "1 day before") and the **raw**
+ * `CalendarContract.Reminders.MINUTES` offset the provider stores.
+ *
+ * Calendula schedules no alarms itself: the provider fires a reminder at
+ * `DTSTART − MINUTES` (the Etar model). An all-day event's DTSTART is **UTC
+ * midnight** (see [EventWriteTimes]), so a raw `MINUTES = 1440` ("1 day") lands
+ * on UTC-midnight of the previous day — 02:00 local in CEST, not the morning.
+ *
+ * To fire at a chosen wall-clock time we encode that time *into* the offset:
+ * `MINUTES = UTC-midnight(startDate) − (localInstant of [timeOfDayMinutes] on the
+ * day [semanticMinutes] before)`. The single fixed offset can only be tuned for
+ * the event's own date, so a recurring all-day series or a post-creation
+ * timezone change drifts the fire time by the offset delta (±1h across DST) —
+ * an inherent limit of the provider model, shared by Etar.
+ */
+private const val MINUTES_PER_DAY = 1_440
+private const val MILLIS_PER_MINUTE = 60_000L
+
+/**
+ * Raw provider `MINUTES` for an all-day reminder set [semanticMinutes] before the
+ * event (a whole-day multiple; sub-day remainders are dropped), so it fires at
+ * [timeOfDayMinutes] (minutes from local midnight) in [zone]. The result may be
+ * **negative** — e.g. "at time of event" at 09:00 CEST encodes to −420, meaning
+ * the provider fires *after* DTSTART; this is valid and must not be clamped.
+ * A negative [semanticMinutes] is the "provider default" sentinel and passes
+ * through unchanged.
+ */
+internal fun toProviderAllDayMinutes(
+    semanticMinutes: Int,
+    startDate: LocalDate,
+    zone: ZoneId,
+    timeOfDayMinutes: Int,
+): Int {
+    if (semanticMinutes < 0) return semanticMinutes
+    val utcMidnight = startDate.atStartOfDay(ZoneOffset.UTC).toInstant().toEpochMilli()
+    val fire = startDate.minusDays((semanticMinutes / MINUTES_PER_DAY).toLong())
+        .atTime(LocalTime.of(timeOfDayMinutes / 60, timeOfDayMinutes % 60))
+        .atZone(zone).toInstant().toEpochMilli()
+    return ((utcMidnight - fire) / MILLIS_PER_MINUTE).toInt()
+}
+
+/**
+ * Recover the semantic whole-day lead time from a raw all-day reminder
+ * [rawMinutes]. Keys off the **local date** of the encoded fire instant, so it
+ * returns the right day count regardless of which [timeOfDayMinutes] wrote the
+ * row — including pre-feature rows (raw multiples of 1440, fired at UTC midnight)
+ * and rows written under a different timezone. A negative [rawMinutes] (fire
+ * after DTSTART) folds to day 0.
+ */
+internal fun fromProviderAllDayMinutes(
+    rawMinutes: Int,
+    startDate: LocalDate,
+    zone: ZoneId,
+): Int {
+    val utcMidnight = startDate.atStartOfDay(ZoneOffset.UTC).toInstant().toEpochMilli()
+    val fireLocalDate = Instant.ofEpochMilli(utcMidnight - rawMinutes * MILLIS_PER_MINUTE)
+        .atZone(zone).toLocalDate()
+    return ChronoUnit.DAYS.between(fireLocalDate, startDate).toInt() * MINUTES_PER_DAY
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/CalendarDataSource.kt

@@ -2,17 +2,31 @@ package de.jeanlucmakiola.calendula.data.calendar
 
 import android.content.ContentResolver
 import android.content.ContentUris
+import android.content.ContentValues
 import android.content.Context
 import android.database.ContentObserver
 import android.database.Cursor
+import android.net.Uri
 import android.os.Handler
 import android.os.Looper
 import android.provider.CalendarContract
+import android.util.Log
 import dagger.hilt.android.qualifiers.ApplicationContext
 import de.jeanlucmakiola.calendula.domain.Attendee
 import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventColorOption
 import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.EventStatus
+import de.jeanlucmakiola.calendula.domain.Reminder
+import de.jeanlucmakiola.calendula.domain.ics.IcsEvent
+import de.jeanlucmakiola.calendula.domain.ics.ParsedIcsEvent
+import de.jeanlucmakiola.calendula.domain.rruleTruncatedAt
+import kotlinx.datetime.toJavaLocalDate
+import java.time.ZoneId
+import java.time.ZoneOffset
+import java.util.UUID
 import javax.inject.Inject
 import javax.inject.Singleton
 
@@ -28,6 +42,116 @@ interface CalendarDataSource {
     fun calendars(): List<CalendarSource>
     fun instances(beginMillis: Long, endMillis: Long): List<EventInstance>
     fun eventDetail(eventId: Long): EventDetail?
+
+    /**
+     * The event-colour palette the calendar's account publishes
+     * (`CalendarContract.Colors`, `TYPE_EVENT`), sorted by key. Empty when the
+     * account exposes no palette (most local calendars, some CalDAV) — the
+     * signal that a custom colour can only be written as a raw `EVENT_COLOR`,
+     * which a synced calendar may drop on its next sync.
+     */
+    fun eventColorPalette(calendarId: Long): List<EventColorOption>
+
+    /**
+     * Every master/one-off event of the writable local calendars, mapped for a
+     * whole-calendar `.ics` backup. Modified-occurrence and cancelled-exception
+     * rows are excluded (see [EventExportProjection]).
+     */
+    fun exportableEvents(): List<IcsEvent>
+
+    /**
+     * The non-empty `Events.UID_2445` values present in [calendarId] — used to
+     * dedup an `.ics` import so re-importing a backup doesn't double events.
+     */
+    fun existingUids(calendarId: Long): Set<String>
+
+    /**
+     * Insert a parsed `.ics` event into [calendarId], preserving its UID (or
+     * minting one when absent); returns the new `Events._ID`. Reminders are
+     * written as the file's raw lead minutes (METHOD_ALERT).
+     */
+    fun insertImportedEvent(event: ParsedIcsEvent, calendarId: Long): Long
+
+    /**
+     * Create a new device-only (`ACCOUNT_TYPE_LOCAL`) calendar the app owns;
+     * returns its `Calendars._ID`. Inserted through the sync-adapter URI so the
+     * provider keeps the row (a plain insert is rejected for the LOCAL account).
+     */
+    fun createLocalCalendar(displayName: String, color: Int, description: String?): Long
+
+    /** Update name, color and description of a local calendar the app owns. */
+    fun updateCalendar(id: Long, displayName: String, color: Int, description: String?)
+
+    /** Permanently delete a local calendar the app owns, with all its events. */
+    fun deleteCalendar(id: Long)
+
+    /**
+     * Insert a new event; returns the new `Events._ID`. [allDayReminderTimeMinutes]
+     * (minutes from local midnight) is the wall-clock time all-day reminders
+     * should fire at — encoded into each all-day reminder's provider offset
+     * (ignored for timed events).
+     */
+    fun insertEvent(form: EventForm, allDayReminderTimeMinutes: Int): Long
+
+    /**
+     * Update an existing event (for recurring events: the whole series) to
+     * match [updated]. [original] is the form as it was prefilled from the
+     * event, so only fields the user actually changed are written and the
+     * reminder rows can be diffed instead of wiped.
+     * [allDayReminderTimeMinutes]: see [insertEvent].
+     */
+    fun updateEvent(
+        eventId: Long,
+        original: EventForm,
+        updated: EventForm,
+        allDayReminderTimeMinutes: Int,
+    )
+
+    /**
+     * Change a single occurrence of a recurring event by inserting a
+     * modified-occurrence exception at [beginMillis] (the occurrence's
+     * `Instances.BEGIN`) carrying [form]'s values; returns the exception
+     * row's `Events._ID`. [allDayReminderTimeMinutes]: see [insertEvent].
+     */
+    fun updateOccurrence(
+        eventId: Long,
+        beginMillis: Long,
+        form: EventForm,
+        allDayReminderTimeMinutes: Int,
+    ): Long
+
+    /**
+     * Change a recurring event from the occurrence at [beginMillis] onwards
+     * by splitting the series: the existing RRULE ends just before the
+     * occurrence and a new event with [updated]'s values (and rule) starts
+     * there; returns the new event's `Events._ID`. From the first occurrence
+     * this is a plain series update. A carried-over COUNT restarts counting
+     * in the new series (we don't recompute the remaining occurrences).
+     */
+    fun updateEventFromOccurrence(
+        eventId: Long,
+        beginMillis: Long,
+        original: EventForm,
+        updated: EventForm,
+        allDayReminderTimeMinutes: Int,
+    ): Long
+
+    /**
+     * Delete a recurring event from the occurrence at [beginMillis] onwards
+     * by ending the series RRULE just before it. Deleting from the first
+     * occurrence removes the whole event.
+     */
+    fun deleteEventFromOccurrence(eventId: Long, beginMillis: Long)
+
+    /** Delete the whole event (for recurring events: the entire series). */
+    fun deleteEvent(eventId: Long)
+
+    /**
+     * Cancel a single occurrence of a recurring event by inserting a
+     * cancelled exception at [beginMillis] (the occurrence's `Instances.BEGIN`).
+     */
+    fun deleteOccurrence(eventId: Long, beginMillis: Long)
+
     fun registerChangeListener(listener: () -> Unit)
     fun unregisterChangeListener(listener: () -> Unit)
 }
@@ -47,6 +171,76 @@ class AndroidCalendarDataSource @Inject constructor(
         CalendarContract.Calendars.CALENDAR_DISPLAY_NAME + " ASC",
     )?.use { it.mapAll(::toCalendarSource) } ?: emptyList()
 
+    /**
+     * Calendar-row writes must address the provider as a sync adapter and name
+     * the account in the URI; otherwise inserts/deletes for the LOCAL account
+     * are silently dropped or only soft-deleted.
+     */
+    private fun localCalendarsUri(): Uri = CalendarContract.Calendars.CONTENT_URI.buildUpon()
+        .appendQueryParameter(CalendarContract.CALLER_IS_SYNCADAPTER, "true")
+        .appendQueryParameter(CalendarContract.Calendars.ACCOUNT_NAME, LOCAL_ACCOUNT_NAME)
+        .appendQueryParameter(
+            CalendarContract.Calendars.ACCOUNT_TYPE,
+            CalendarContract.ACCOUNT_TYPE_LOCAL,
+        )
+        .build()
+
+    override fun createLocalCalendar(displayName: String, color: Int, description: String?): Long {
+        val name = displayName.trim().ifEmpty { Fallbacks.UNNAMED_CALENDAR }
+        val values = ContentValues().apply {
+            put(CalendarContract.Calendars.ACCOUNT_NAME, LOCAL_ACCOUNT_NAME)
+            put(CalendarContract.Calendars.ACCOUNT_TYPE, CalendarContract.ACCOUNT_TYPE_LOCAL)
+            put(CalendarContract.Calendars.OWNER_ACCOUNT, LOCAL_ACCOUNT_NAME)
+            // NAME is the sync-adapter id; DISPLAY_NAME is what the user sees.
+            put(CalendarContract.Calendars.NAME, name)
+            put(CalendarContract.Calendars.CALENDAR_DISPLAY_NAME, name)
+            put(CalendarContract.Calendars.CALENDAR_COLOR, color)
+            put(
+                CalendarContract.Calendars.CALENDAR_ACCESS_LEVEL,
+                CalendarContract.Calendars.CAL_ACCESS_OWNER,
+            )
+            put(CalendarContract.Calendars.VISIBLE, 1)
+            put(CalendarContract.Calendars.SYNC_EVENTS, 1)
+            putDescription(description)
+        }
+        val uri = resolver.insert(localCalendarsUri(), values)
+            ?: throw WriteFailedException("create local calendar '$name'")
+        return ContentUris.parseId(uri)
+    }
+
+    override fun updateCalendar(id: Long, displayName: String, color: Int, description: String?) {
+        val name = displayName.trim().ifEmpty { Fallbacks.UNNAMED_CALENDAR }
+        val values = ContentValues().apply {
+            put(CalendarContract.Calendars.CALENDAR_DISPLAY_NAME, name)
+            put(CalendarContract.Calendars.NAME, name)
+            put(CalendarContract.Calendars.CALENDAR_COLOR, color)
+            putDescription(description)
+        }
+        val rows = resolver.update(
+            ContentUris.withAppendedId(localCalendarsUri(), id),
+            values, null, null,
+        )
+        if (rows == 0) throw WriteFailedException("update calendar id=$id")
+    }
+
+    /** Store the description in CAL_SYNC1, or clear it when blank/absent. */
+    private fun ContentValues.putDescription(description: String?) {
+        val text = description?.trim().orEmpty()
+        if (text.isEmpty()) {
+            putNull(CalendarProjection.DESCRIPTION_COLUMN)
+        } else {
+            put(CalendarProjection.DESCRIPTION_COLUMN, text)
+        }
+    }
+
+    override fun deleteCalendar(id: Long) {
+        val deleted = resolver.delete(
+            ContentUris.withAppendedId(localCalendarsUri(), id),
+            null, null,
+        )
+        if (deleted == 0) throw WriteFailedException("delete calendar id=$id")
+    }
+
     override fun instances(beginMillis: Long, endMillis: Long): List<EventInstance> {
         val uri = CalendarContract.Instances.CONTENT_URI.buildUpon().apply {
             ContentUris.appendId(this, beginMillis)
@@ -62,16 +256,462 @@ class AndroidCalendarDataSource @Inject constructor(
 
     override fun eventDetail(eventId: Long): EventDetail? {
         val attendees = queryAttendees(eventId)
+        val reminders = queryReminders(eventId)
         return resolver.query(
             ContentUris.withAppendedId(CalendarContract.Events.CONTENT_URI, eventId),
             EventDetailProjection.COLUMNS,
             null, null, null,
         )?.use { c ->
             if (!c.moveToFirst()) null
-            else CursorColumnReader(c).toEventDetailCore(attendees)
+            else CursorColumnReader(c).toEventDetailCore(attendees, reminders)
         }
     }
 
+    override fun eventColorPalette(calendarId: Long): List<EventColorOption> {
+        val account = calendarAccount(calendarId) ?: return emptyList()
+        return resolver.query(
+            CalendarContract.Colors.CONTENT_URI,
+            arrayOf(CalendarContract.Colors.COLOR_KEY, CalendarContract.Colors.COLOR),
+            CalendarContract.Colors.ACCOUNT_NAME + " = ? AND " +
+                CalendarContract.Colors.ACCOUNT_TYPE + " = ? AND " +
+                CalendarContract.Colors.COLOR_TYPE + " = ?",
+            arrayOf(
+                account.name,
+                account.type,
+                CalendarContract.Colors.TYPE_EVENT.toString(),
+            ),
+            null,
+        )?.use { c ->
+            c.mapAll { EventColorOption(key = it.getString(0).orEmpty(), argb = it.getInt(1)) }
+        }
+            ?.filter { it.key.isNotEmpty() }
+            ?.sortedBy { it.key }
+            ?: emptyList()
+    }
+
+    override fun exportableEvents(): List<IcsEvent> {
+        // Only the local calendars the app owns and can write — synced calendars
+        // already have a backup (their server). Map id → display name for the
+        // X-CALENDULA-CALENDAR tag a restore uses to fan back out.
+        val names = calendars()
+            .filter { it.isLocal && it.canModifyContents }
+            .associate { it.id to it.displayName }
+        if (names.isEmpty()) return emptyList()
+
+        val idList = names.keys.joinToString(",")
+        return resolver.query(
+            CalendarContract.Events.CONTENT_URI,
+            EventExportProjection.COLUMNS,
+            // Skip soft-deleted rows and exception rows (modified occurrences /
+            // cancellations) — v1 exports masters + one-offs only.
+            "${CalendarContract.Events.CALENDAR_ID} IN ($idList) AND " +
+                "${CalendarContract.Events.DELETED} = 0 AND " +
+                "${CalendarContract.Events.ORIGINAL_ID} IS NULL",
+            null,
+            CalendarContract.Events.DTSTART + " ASC",
+        )?.use { c ->
+            c.mapAll {
+                val reader = CursorColumnReader(c)
+                val eventId = reader.getLong(EventExportProjection.IDX_ID)
+                val calendarId = reader.getLong(EventExportProjection.IDX_CALENDAR_ID)
+                reader.toIcsEvent(
+                    reminderMinutes = queryReminders(eventId).map { it.minutes },
+                    calendarName = names[calendarId],
+                )
+            }
+        } ?: emptyList()
+    }
+
+    override fun existingUids(calendarId: Long): Set<String> = resolver.query(
+        CalendarContract.Events.CONTENT_URI,
+        arrayOf(CalendarContract.Events.UID_2445),
+        "${CalendarContract.Events.CALENDAR_ID} = ? AND " +
+            "${CalendarContract.Events.UID_2445} IS NOT NULL",
+        arrayOf(calendarId.toString()),
+        null,
+    )?.use { c ->
+        buildSet { while (c.moveToNext()) c.getString(0)?.takeIf { it.isNotEmpty() }?.let(::add) }
+    } ?: emptySet()
+
+    override fun insertImportedEvent(event: ParsedIcsEvent, calendarId: Long): Long {
+        val startMillis = event.start.toEpochMillis()
+        val endMillis = event.end.toEpochMillis()
+        val values = ContentValues().apply {
+            put(CalendarContract.Events.CALENDAR_ID, calendarId)
+            // Preserve the file's UID so a re-import dedups against it; mint one
+            // only when the source event carried none.
+            put(
+                CalendarContract.Events.UID_2445,
+                event.uid?.takeIf { it.isNotBlank() } ?: "${UUID.randomUUID()}@calendula",
+            )
+            put(CalendarContract.Events.TITLE, event.summary.trim())
+            put(CalendarContract.Events.ALL_DAY, if (event.isAllDay) 1 else 0)
+            put(CalendarContract.Events.DTSTART, startMillis)
+            if (event.recurrenceRule == null) {
+                put(CalendarContract.Events.DTEND, endMillis)
+            } else {
+                put(CalendarContract.Events.RRULE, event.recurrenceRule)
+                put(
+                    CalendarContract.Events.DURATION,
+                    importDuration(startMillis, endMillis, event.isAllDay),
+                )
+            }
+            // All-day rows live at UTC midnights (the file already encodes them so);
+            // timed rows keep the event's own zone.
+            put(CalendarContract.Events.EVENT_TIMEZONE, if (event.isAllDay) "UTC" else event.zoneId)
+            put(CalendarContract.Events.AVAILABILITY, event.availability.toProviderValue())
+            put(CalendarContract.Events.STATUS, event.status.toProviderStatus())
+            event.location?.trim()?.takeIf { it.isNotEmpty() }
+                ?.let { put(CalendarContract.Events.EVENT_LOCATION, it) }
+            event.description?.trim()?.takeIf { it.isNotEmpty() }
+                ?.let { put(CalendarContract.Events.DESCRIPTION, it) }
+        }
+        val uri = resolver.insert(CalendarContract.Events.CONTENT_URI, values)
+            ?: throw WriteFailedException("import event into calendar id=$calendarId")
+        val eventId = ContentUris.parseId(uri)
+        // Raw lead minutes straight from the file's VALARMs (best-effort, like insertEvent).
+        event.reminderMinutes.distinct().filter { it >= 0 }.forEach { minutes ->
+            val reminder = ContentValues().apply {
+                put(CalendarContract.Reminders.EVENT_ID, eventId)
+                put(CalendarContract.Reminders.MINUTES, minutes)
+                put(CalendarContract.Reminders.METHOD, CalendarContract.Reminders.METHOD_ALERT)
+            }
+            if (resolver.insert(CalendarContract.Reminders.CONTENT_URI, reminder) == null) {
+                Log.w(TAG, "Failed to attach reminder ($minutes min) to imported event $eventId")
+            }
+        }
+        return eventId
+    }
+
+    /** Provider DURATION for an imported recurring row: whole days / seconds. */
+    private fun importDuration(startMillis: Long, endMillis: Long, isAllDay: Boolean): String {
+        val span = (endMillis - startMillis).coerceAtLeast(0)
+        return if (isAllDay) "P${span / 86_400_000L}D" else "P${span / 1_000L}S"
+    }
+
+    private fun EventStatus.toProviderStatus(): Int = when (this) {
+        EventStatus.Confirmed -> CalendarContract.Events.STATUS_CONFIRMED
+        EventStatus.Tentative -> CalendarContract.Events.STATUS_TENTATIVE
+        EventStatus.Cancelled -> CalendarContract.Events.STATUS_CANCELED
+    }
+
+    /** The account a calendar belongs to, for scoping a `Colors` lookup. */
+    private fun calendarAccount(calendarId: Long): CalendarAccount? = resolver.query(
+        ContentUris.withAppendedId(CalendarContract.Calendars.CONTENT_URI, calendarId),
+        arrayOf(
+            CalendarContract.Calendars.ACCOUNT_NAME,
+            CalendarContract.Calendars.ACCOUNT_TYPE,
+        ),
+        null, null, null,
+    )?.use { c ->
+        if (c.moveToFirst()) {
+            CalendarAccount(name = c.getString(0).orEmpty(), type = c.getString(1).orEmpty())
+        } else {
+            null
+        }
+    }
+
+    private data class CalendarAccount(val name: String, val type: String)
+
+    /**
+     * The raw provider `MINUTES` to store for one of [form]'s reminders: an
+     * all-day reminder is shifted to fire at [allDayReminderTimeMinutes] local
+     * (see [toProviderAllDayMinutes]); a timed reminder is its lead time as-is.
+     */
+    private fun providerReminderMinutes(
+        form: EventForm,
+        minutes: Int,
+        allDayReminderTimeMinutes: Int,
+    ): Int = if (form.isAllDay) {
+        toProviderAllDayMinutes(
+            semanticMinutes = minutes,
+            startDate = form.start.date.toJavaLocalDate(),
+            zone = ZoneId.systemDefault(),
+            timeOfDayMinutes = allDayReminderTimeMinutes,
+        )
+    } else {
+        minutes
+    }
+
+    /** [form]'s reminders as the distinct raw provider offsets to store. */
+    private fun encodedReminders(form: EventForm, allDayReminderTimeMinutes: Int): List<Int> =
+        form.reminders
+            .map { providerReminderMinutes(form, it, allDayReminderTimeMinutes) }
+            .distinct()
+
+    override fun insertEvent(form: EventForm, allDayReminderTimeMinutes: Int): Long {
+        val times = form.toWriteTimes(ZoneId.systemDefault())
+        val values = ContentValues().apply {
+            put(
+                CalendarContract.Events.CALENDAR_ID,
+                requireNotNull(form.calendarId) { "EventForm.calendarId is required" },
+            )
+            // A globally-unique UID so a later .ics backup/restore can identify
+            // the event and not duplicate it on re-import (the provider leaves
+            // this null for events it didn't sync). Older rows without one fall
+            // back to a stable synthesised UID at export time (deriveIcsUid).
+            put(CalendarContract.Events.UID_2445, "${UUID.randomUUID()}@calendula")
+            put(CalendarContract.Events.TITLE, form.title.trim())
+            put(CalendarContract.Events.ALL_DAY, if (form.isAllDay) 1 else 0)
+            put(CalendarContract.Events.DTSTART, times.dtStartMillis)
+            // The provider's invariant: recurring rows carry RRULE+DURATION
+            // (and no DTEND), one-off rows carry DTEND.
+            if (form.rrule == null) {
+                put(CalendarContract.Events.DTEND, times.dtEndMillis)
+            } else {
+                put(CalendarContract.Events.RRULE, form.rrule)
+                put(CalendarContract.Events.DURATION, times.toRfc2445Duration(form.isAllDay))
+            }
+            put(CalendarContract.Events.EVENT_TIMEZONE, times.timezone)
+            put(CalendarContract.Events.AVAILABILITY, form.availability.toProviderValue())
+            put(CalendarContract.Events.ACCESS_LEVEL, form.accessLevel.toProviderValue())
+            form.location.trim().takeIf { it.isNotEmpty() }
+                ?.let { put(CalendarContract.Events.EVENT_LOCATION, it) }
+            form.description.trim().takeIf { it.isNotEmpty() }
+                ?.let { put(CalendarContract.Events.DESCRIPTION, it) }
+            // A null colour just leaves both columns unset (the event inherits
+            // its calendar's colour), so only the key/raw cases are written.
+            when {
+                form.colorKey != null ->
+                    put(CalendarContract.Events.EVENT_COLOR_KEY, form.colorKey)
+                form.color != null -> put(CalendarContract.Events.EVENT_COLOR, form.color)
+            }
+        }
+        val uri = resolver.insert(CalendarContract.Events.CONTENT_URI, values)
+            ?: throw WriteFailedException("insert event into calendar id=${form.calendarId}")
+        val eventId = ContentUris.parseId(uri)
+        // Best effort (spec §8): the event exists at this point — a reminder
+        // that fails to attach is logged, not surfaced as a failed create.
+        encodedReminders(form, allDayReminderTimeMinutes)
+            .forEach { minutes ->
+                val reminder = ContentValues().apply {
+                    put(CalendarContract.Reminders.EVENT_ID, eventId)
+                    put(CalendarContract.Reminders.MINUTES, minutes)
+                    put(CalendarContract.Reminders.METHOD, CalendarContract.Reminders.METHOD_ALERT)
+                }
+                if (resolver.insert(CalendarContract.Reminders.CONTENT_URI, reminder) == null) {
+                    Log.w(TAG, "Failed to attach reminder ($minutes min) to event $eventId")
+                }
+            }
+        return eventId
+    }
+
+    override fun updateEvent(
+        eventId: Long,
+        original: EventForm,
+        updated: EventForm,
+        allDayReminderTimeMinutes: Int,
+    ) {
+        val values = buildEventUpdateValues(
+            original = original,
+            updated = updated,
+            seriesDtStartMillis = querySeriesRow(eventId).dtStartMillis,
+            zone = ZoneId.systemDefault(),
+        )
+        if (values.isNotEmpty()) {
+            val rows = resolver.update(
+                ContentUris.withAppendedId(CalendarContract.Events.CONTENT_URI, eventId),
+                values.toContentValues(),
+                null, null,
+            )
+            if (rows == 0) throw WriteFailedException("update event id=$eventId")
+        }
+        // Untouched reminder sets are left alone so unrelated edits can't
+        // disturb provider rows the form never knew about. The diff is on the
+        // form's semantic minutes; reconcile works in encoded provider minutes.
+        if (updated.reminders.toSet() != original.reminders.toSet()) {
+            reconcileReminders(eventId, encodedReminders(updated, allDayReminderTimeMinutes))
+        }
+    }
+
+    override fun updateOccurrence(
+        eventId: Long,
+        beginMillis: Long,
+        form: EventForm,
+        allDayReminderTimeMinutes: Int,
+    ): Long {
+        // The provider clones the series row and applies these values on top.
+        val values = buildOccurrenceExceptionValues(
+            form = form,
+            originalInstanceMillis = beginMillis,
+            zone = ZoneId.systemDefault(),
+        )
+        val uri = resolver.insert(
+            ContentUris.withAppendedId(CalendarContract.Events.CONTENT_EXCEPTION_URI, eventId),
+            values.toContentValues(),
+        ) ?: throw WriteFailedException("modify occurrence event id=$eventId begin=$beginMillis")
+        val exceptionId = ContentUris.parseId(uri)
+        // Whether the provider copied the parent's reminder rows is its
+        // business — reconciling against the actual rows handles both ways.
+        reconcileReminders(exceptionId, encodedReminders(form, allDayReminderTimeMinutes))
+        return exceptionId
+    }
+
+    override fun updateEventFromOccurrence(
+        eventId: Long,
+        beginMillis: Long,
+        original: EventForm,
+        updated: EventForm,
+        allDayReminderTimeMinutes: Int,
+    ): Long {
+        val row = querySeriesRow(eventId)
+        // From the first occurrence on (or with no rule to split) this is
+        // just a series update.
+        if (row.rrule.isNullOrBlank() || beginMillis <= row.dtStartMillis) {
+            updateEvent(eventId, original, updated, allDayReminderTimeMinutes)
+            return eventId
+        }
+        // Insert the new series first: if it fails, the original is untouched.
+        val newEventId = insertEvent(updated, allDayReminderTimeMinutes)
+        truncateSeries(eventId, row, beginMillis)
+        return newEventId
+    }
+
+    override fun deleteEventFromOccurrence(eventId: Long, beginMillis: Long) {
+        val row = querySeriesRow(eventId)
+        // From the first occurrence on = the whole series; also the fallback
+        // when there is no RRULE to truncate.
+        if (row.rrule.isNullOrBlank() || beginMillis <= row.dtStartMillis) {
+            deleteEvent(eventId)
+            return
+        }
+        truncateSeries(eventId, row, beginMillis)
+    }
+
+    /**
+     * End [row]'s series just before the occurrence at [beginMillis]. The
+     * provider regenerates an event's cached instances only from the values
+     * carried by the update itself — an RRULE-only update leaves the old
+     * instances standing (observed on-device: the truncated occurrence kept
+     * showing) — so the entire time-related set travels together, with only
+     * the RRULE actually changing.
+     */
+    private fun truncateSeries(eventId: Long, row: SeriesRow, beginMillis: Long) {
+        requireNotNull(row.rrule) { "truncateSeries needs a recurring row" }
+        val values = ContentValues().apply {
+            put(CalendarContract.Events.DTSTART, row.dtStartMillis)
+            put(CalendarContract.Events.DURATION, row.duration)
+            put(CalendarContract.Events.EVENT_TIMEZONE, row.timezone)
+            put(CalendarContract.Events.ALL_DAY, row.allDay)
+            put(
+                CalendarContract.Events.RRULE,
+                rruleTruncatedAt(row.rrule, untilUtcMillis = row.truncationCutoff(beginMillis)),
+            )
+        }
+        val rows = resolver.update(
+            ContentUris.withAppendedId(CalendarContract.Events.CONTENT_URI, eventId),
+            values,
+            null, null,
+        )
+        if (rows == 0) {
+            throw WriteFailedException("truncate series event id=$eventId begin=$beginMillis")
+        }
+    }
+
+    /** The series anchor: every time-related column of the Events row. */
+    private fun querySeriesRow(eventId: Long): SeriesRow = resolver.query(
+        ContentUris.withAppendedId(CalendarContract.Events.CONTENT_URI, eventId),
+        arrayOf(
+            CalendarContract.Events.DTSTART,
+            CalendarContract.Events.RRULE,
+            CalendarContract.Events.EVENT_TIMEZONE,
+            CalendarContract.Events.DURATION,
+            CalendarContract.Events.ALL_DAY,
+        ),
+        null, null, null,
+    )?.use { c ->
+        if (c.moveToFirst()) {
+            SeriesRow(
+                dtStartMillis = c.getLong(0),
+                rrule = c.getString(1),
+                timezone = c.getString(2),
+                duration = c.getString(3),
+                allDay = c.getInt(4),
+            )
+        } else {
+            null
+        }
+    } ?: throw WriteFailedException("read series row of event id=$eventId")
+
+    private data class SeriesRow(
+        val dtStartMillis: Long,
+        val rrule: String?,
+        val timezone: String?,
+        val duration: String?,
+        val allDay: Int,
+    ) {
+        /** UNTIL cutoff for ending the series before the occurrence at [beginMillis]. */
+        fun truncationCutoff(beginMillis: Long): Long = previousLocalDayEndUtcMillis(
+            beginMillis = beginMillis,
+            zone = runCatching { ZoneId.of(timezone ?: "UTC") }.getOrDefault(ZoneOffset.UTC),
+        )
+    }
+
+    /**
+     * Make the event's reminder rows match [targetMinutes] — the raw provider
+     * offsets to store (already encoded via [encodedReminders], so all-day shifts
+     * are baked in and the diff matches the stored rows). Rows with other offsets
+     * are deleted, missing ones inserted as best-effort ALERTs (like insertEvent).
+     * Rows whose minutes survive keep their method.
+     */
+    private fun reconcileReminders(eventId: Long, targetMinutes: List<Int>) {
+        val target = targetMinutes.toSet()
+        val existing = queryReminders(eventId).map { it.minutes }.toSet()
+        (existing - target).forEach { minutes ->
+            resolver.delete(
+                CalendarContract.Reminders.CONTENT_URI,
+                CalendarContract.Reminders.EVENT_ID + " = ? AND " +
+                    CalendarContract.Reminders.MINUTES + " = ?",
+                arrayOf(eventId.toString(), minutes.toString()),
+            )
+        }
+        (target - existing).forEach { minutes ->
+            val reminder = ContentValues().apply {
+                put(CalendarContract.Reminders.EVENT_ID, eventId)
+                put(CalendarContract.Reminders.MINUTES, minutes)
+                put(CalendarContract.Reminders.METHOD, CalendarContract.Reminders.METHOD_ALERT)
+            }
+            if (resolver.insert(CalendarContract.Reminders.CONTENT_URI, reminder) == null) {
+                Log.w(TAG, "Failed to attach reminder ($minutes min) to event $eventId")
+            }
+        }
+    }
+
+    private fun Map<String, Any?>.toContentValues(): ContentValues =
+        ContentValues().also { cv ->
+            forEach { (column, value) ->
+                when (value) {
+                    null -> cv.putNull(column)
+                    is String -> cv.put(column, value)
+                    is Long -> cv.put(column, value)
+                    is Int -> cv.put(column, value)
+                    else -> error("Unsupported value for $column: $value")
+                }
+            }
+        }
+
+    override fun deleteEvent(eventId: Long) {
+        val deleted = resolver.delete(
+            ContentUris.withAppendedId(CalendarContract.Events.CONTENT_URI, eventId),
+            null, null,
+        )
+        if (deleted == 0) throw WriteFailedException("delete event id=$eventId")
+    }
+
+    override fun deleteOccurrence(eventId: Long, beginMillis: Long) {
+        // A cancelled exception row hides exactly this occurrence; the sync
+        // adapter turns it into an EXDATE/cancelled VEVENT upstream.
+        val values = ContentValues().apply {
+            put(CalendarContract.Events.ORIGINAL_INSTANCE_TIME, beginMillis)
+            put(CalendarContract.Events.STATUS, CalendarContract.Events.STATUS_CANCELED)
+        }
+        val uri = ContentUris.withAppendedId(
+            CalendarContract.Events.CONTENT_EXCEPTION_URI, eventId,
+        )
+        resolver.insert(uri, values)
+            ?: throw WriteFailedException("cancel occurrence event id=$eventId begin=$beginMillis")
+    }
+
     override fun registerChangeListener(listener: () -> Unit) {
         val obs = object : ContentObserver(Handler(Looper.getMainLooper())) {
             override fun onChange(selfChange: Boolean) {
@@ -98,6 +738,14 @@ class AndroidCalendarDataSource @Inject constructor(
         null,
     )?.use { c -> c.mapAll { CursorColumnReader(c).toAttendee() } } ?: emptyList()
 
+    private fun queryReminders(eventId: Long): List<Reminder> = resolver.query(
+        CalendarContract.Reminders.CONTENT_URI,
+        ReminderProjection.COLUMNS,
+        CalendarContract.Reminders.EVENT_ID + " = ?",
+        arrayOf(eventId.toString()),
+        null,
+    )?.use { c -> c.mapAll { CursorColumnReader(c).toReminder() } } ?: emptyList()
+
     private fun toCalendarSource(c: Cursor): CalendarSource = CursorColumnReader(c).toCalendarSource()
 
     /** Iterate every row and map; skips nothing. */
@@ -109,4 +757,14 @@ class AndroidCalendarDataSource @Inject constructor(
     private inline fun <T : Any> Cursor.mapAllNotNull(mapper: (Cursor) -> T?): List<T> = buildList {
         while (moveToNext()) mapper(this@mapAllNotNull)?.let(::add)
     }
+
+    private companion object {
+        const val TAG = "CalendarDataSource"
+
+        /**
+         * Shared account for every app-created local calendar, so they group
+         * together (by account) in the filter sheet and calendar manager.
+         */
+        const val LOCAL_ACCOUNT_NAME = "Calendula"
+    }
 }

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/CalendarMapper.kt

@@ -1,13 +1,28 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
+import android.provider.CalendarContract
 import de.jeanlucmakiola.calendula.domain.CalendarSource
 
-internal fun ColumnReader.toCalendarSource(): CalendarSource = CalendarSource(
+internal fun ColumnReader.toCalendarSource(): CalendarSource {
+    val accountType = getString(CalendarProjection.IDX_ACCOUNT_TYPE).orEmpty()
+    val isLocal = accountType == CalendarContract.ACCOUNT_TYPE_LOCAL
+    return CalendarSource(
         id = getLong(CalendarProjection.IDX_ID),
         displayName = getString(CalendarProjection.IDX_DISPLAY_NAME)
             ?: Fallbacks.UNNAMED_CALENDAR,
         accountName = getString(CalendarProjection.IDX_ACCOUNT_NAME).orEmpty(),
-    accountType = getString(CalendarProjection.IDX_ACCOUNT_TYPE).orEmpty(),
+        accountType = accountType,
         color = getInt(CalendarProjection.IDX_COLOR),
         isVisibleInSystem = getInt(CalendarProjection.IDX_VISIBLE) != 0,
+        canModifyContents = getInt(CalendarProjection.IDX_ACCESS_LEVEL) >=
+            CalendarContract.Calendars.CAL_ACCESS_CONTRIBUTOR,
+        isLocal = isLocal,
+        // CAL_SYNC1 holds the sync token for synced rows, so only treat it as a
+        // user description on the local calendars the app owns.
+        description = if (isLocal) {
+            getString(CalendarProjection.IDX_DESCRIPTION)?.takeIf { it.isNotBlank() }
+        } else {
+            null
+        },
     )
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/CalendarRepository.kt

@@ -1,8 +1,13 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
 import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventColorOption
 import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.ics.IcsEvent
+import de.jeanlucmakiola.calendula.domain.ics.IcsImportSummary
+import de.jeanlucmakiola.calendula.domain.ics.ParsedIcsEvent
 import kotlinx.coroutines.flow.Flow
 import kotlin.time.Instant
 
@@ -10,7 +15,74 @@ interface CalendarRepository {
     fun calendars(): Flow<List<CalendarSource>>
     fun instances(range: ClosedRange<Instant>): Flow<List<EventInstance>>
     suspend fun eventDetail(eventId: Long): EventDetail
+
+    /**
+     * The event-colour palette a calendar's account publishes; empty when it
+     * exposes none (see [CalendarDataSource.eventColorPalette]).
+     */
+    suspend fun eventColorPalette(calendarId: Long): List<EventColorOption>
+
+    /** Create a device-only (LOCAL) calendar the app owns; returns its id. */
+    suspend fun createLocalCalendar(displayName: String, color: Int, description: String?): Long
+
+    /** Update name, color and description of a local calendar the app owns. */
+    suspend fun updateCalendar(id: Long, displayName: String, color: Int, description: String?)
+
+    /** Permanently delete a local calendar the app owns, with all its events. */
+    suspend fun deleteCalendar(id: Long)
+
+    /**
+     * Every event of the writable local calendars, ready to serialise into a
+     * whole-calendar `.ics` backup (see [CalendarDataSource.exportableEvents]).
+     */
+    suspend fun exportEvents(): List<IcsEvent>
+
+    /**
+     * Bulk-import parsed `.ics` [events] into [targetCalendarId]. Events whose
+     * UID already exists in the target are skipped (idempotent restore); the
+     * rest are inserted. See [CalendarDataSource.insertImportedEvent].
+     */
+    suspend fun importEvents(targetCalendarId: Long, events: List<ParsedIcsEvent>): IcsImportSummary
+
+    /** Create a new event from a validated form; returns the new `Events._ID`. */
+    suspend fun createEvent(form: EventForm): Long
+
+    /**
+     * Update an event (recurring: the whole series) from a validated form.
+     * [original] is the prefilled form, used to write only what changed.
+     */
+    suspend fun updateEvent(eventId: Long, original: EventForm, updated: EventForm)
+
+    /**
+     * Change a single occurrence of a recurring event (exception row with the
+     * form's values); returns the exception's `Events._ID`.
+     */
+    suspend fun updateOccurrence(eventId: Long, beginMillis: Long, form: EventForm): Long
+
+    /**
+     * Change a recurring event from [beginMillis] onwards (series split);
+     * returns the new event's `Events._ID`.
+     */
+    suspend fun updateEventFromOccurrence(
+        eventId: Long,
+        beginMillis: Long,
+        original: EventForm,
+        updated: EventForm,
+    ): Long
+
+    /** Delete the whole event (for recurring events: the entire series). */
+    suspend fun deleteEvent(eventId: Long)
+
+    /** Cancel a single occurrence of a recurring event at its `Instances.BEGIN` time. */
+    suspend fun deleteOccurrence(eventId: Long, beginMillis: Long)
+
+    /** Delete a recurring event from the occurrence at [beginMillis] onwards. */
+    suspend fun deleteEventFromOccurrence(eventId: Long, beginMillis: Long)
 }
 
 class NoSuchEventException(eventId: Long) :
     NoSuchElementException("No event with id=$eventId")
+
+/** A ContentResolver write affected no rows or returned no URI. */
+class WriteFailedException(operation: String) :
+    RuntimeException("Calendar write failed: $operation")

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/CalendarRepositoryImpl.kt

@@ -1,12 +1,20 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
 import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
 import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventColorOption
 import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.ics.IcsImportSummary
+import de.jeanlucmakiola.calendula.domain.ics.ParsedIcsEvent
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.onStart
@@ -23,9 +31,15 @@ import javax.inject.Singleton
 @Singleton
 class CalendarRepositoryImpl @Inject constructor(
     private val dataSource: CalendarDataSource,
+    private val prefs: CalendarPrefs,
+    private val settingsPrefs: SettingsPrefs,
     @IoDispatcher private val io: CoroutineDispatcher,
 ) : CalendarRepository {
 
+    /** The configured wall-clock fire time for all-day reminders, read per write. */
+    private suspend fun allDayReminderTimeMinutes(): Int =
+        settingsPrefs.allDayReminderTimeMinutes.first()
+
     private val ticks = MutableSharedFlow<Unit>(
         replay = 0,
         extraBufferCapacity = 1,
@@ -41,7 +55,13 @@ class CalendarRepositoryImpl @Inject constructor(
             .reQuery { dataSource.calendars() }
             .flowOn(io)
 
+    // Instances are filtered by the app-side hidden-calendar set (M3): an event
+    // is dropped whenever the user has hidden its calendar. Re-runs when the
+    // provider ticks *or* the hidden set changes — toggling a calendar in the
+    // filter sheet updates every view immediately. [calendars] stays unfiltered
+    // so the filter sheet can list and re-enable hidden calendars.
     override fun instances(range: ClosedRange<Instant>): Flow<List<EventInstance>> =
+        combine(
             ticks
                 .onStart { emit(Unit) }
                 .reQuery {
@@ -49,12 +69,105 @@ class CalendarRepositoryImpl @Inject constructor(
                         beginMillis = range.start.toEpochMillis(),
                         endMillis = range.endInclusive.toEpochMillis(),
                     )
-            }
-            .flowOn(io)
+                },
+            prefs.hiddenCalendarIds,
+        ) { instances, hidden ->
+            if (hidden.isEmpty()) instances
+            else instances.filterNot { it.calendarId in hidden }
+        }.flowOn(io)
 
     override suspend fun eventDetail(eventId: Long): EventDetail = withContext(io) {
         dataSource.eventDetail(eventId) ?: throw NoSuchEventException(eventId)
     }
+
+    override suspend fun eventColorPalette(calendarId: Long): List<EventColorOption> =
+        withContext(io) { dataSource.eventColorPalette(calendarId) }
+
+    override suspend fun createLocalCalendar(
+        displayName: String,
+        color: Int,
+        description: String?,
+    ): Long = withContext(io) {
+        dataSource.createLocalCalendar(displayName, color, description)
+    }
+
+    override suspend fun updateCalendar(
+        id: Long,
+        displayName: String,
+        color: Int,
+        description: String?,
+    ) = withContext(io) { dataSource.updateCalendar(id, displayName, color, description) }
+
+    override suspend fun deleteCalendar(id: Long) =
+        withContext(io) { dataSource.deleteCalendar(id) }
+
+    override suspend fun exportEvents() = withContext(io) { dataSource.exportableEvents() }
+
+    override suspend fun importEvents(
+        targetCalendarId: Long,
+        events: List<ParsedIcsEvent>,
+    ): IcsImportSummary = withContext(io) {
+        val existing = dataSource.existingUids(targetCalendarId)
+        var imported = 0
+        var skipped = 0
+        for (event in events) {
+            // A known UID means the event is already in this calendar — skip,
+            // keeping a restore idempotent (no overwrite this pass).
+            if (event.uid != null && event.uid in existing) {
+                skipped++
+            } else {
+                dataSource.insertImportedEvent(event, targetCalendarId)
+                imported++
+            }
+        }
+        IcsImportSummary(imported = imported, skippedDuplicate = skipped)
+    }
+
+    override suspend fun createEvent(form: EventForm): Long = withContext(io) {
+        dataSource.insertEvent(form, allDayReminderTimeMinutes())
+    }
+
+    override suspend fun updateEvent(
+        eventId: Long,
+        original: EventForm,
+        updated: EventForm,
+    ) = withContext(io) {
+        dataSource.updateEvent(eventId, original, updated, allDayReminderTimeMinutes())
+    }
+
+    override suspend fun deleteEvent(eventId: Long) = withContext(io) {
+        dataSource.deleteEvent(eventId)
+    }
+
+    override suspend fun updateOccurrence(
+        eventId: Long,
+        beginMillis: Long,
+        form: EventForm,
+    ): Long = withContext(io) {
+        dataSource.updateOccurrence(eventId, beginMillis, form, allDayReminderTimeMinutes())
+    }
+
+    override suspend fun updateEventFromOccurrence(
+        eventId: Long,
+        beginMillis: Long,
+        original: EventForm,
+        updated: EventForm,
+    ): Long = withContext(io) {
+        dataSource.updateEventFromOccurrence(
+            eventId, beginMillis, original, updated, allDayReminderTimeMinutes(),
+        )
+    }
+
+    override suspend fun deleteOccurrence(eventId: Long, beginMillis: Long) = withContext(io) {
+        dataSource.deleteOccurrence(eventId, beginMillis)
+    }
+
+    override suspend fun deleteEventFromOccurrence(
+        eventId: Long,
+        beginMillis: Long,
+    ) = withContext(io) {
+        dataSource.deleteEventFromOccurrence(eventId, beginMillis)
+    }
 }
 
 private fun <T> Flow<Unit>.reQuery(block: suspend () -> T): Flow<T> = flow {

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/EventDetailMapper.kt

@@ -2,36 +2,66 @@ package de.jeanlucmakiola.calendula.data.calendar
 
 import android.provider.CalendarContract
 import android.util.Log
+import de.jeanlucmakiola.calendula.domain.AccessLevel
 import de.jeanlucmakiola.calendula.domain.Attendee
+import de.jeanlucmakiola.calendula.domain.AttendeeRelationship
 import de.jeanlucmakiola.calendula.domain.AttendeeStatus
+import de.jeanlucmakiola.calendula.domain.AttendeeType
+import de.jeanlucmakiola.calendula.domain.Availability
 import de.jeanlucmakiola.calendula.domain.EventDetail
 import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.EventStatus
+import de.jeanlucmakiola.calendula.domain.Reminder
+import de.jeanlucmakiola.calendula.domain.ReminderMethod
+import java.time.Instant
+import java.time.ZoneId
+import java.time.ZoneOffset
 
 private const val TAG = "EventDetailMapper"
 
-internal fun ColumnReader.toEventDetailCore(attendees: List<Attendee>): EventDetail? {
+internal fun ColumnReader.toEventDetailCore(
+    attendees: List<Attendee>,
+    reminders: List<Reminder>,
+): EventDetail? {
     val begin = getLong(EventDetailProjection.IDX_DTSTART)
-    val end = getLong(EventDetailProjection.IDX_DTEND)
 
     if (begin < 0L) {
         Log.w(TAG, "Dropping event with negative dtstart=$begin")
         return null
     }
-    if (end < begin) {
-        Log.w(TAG, "Dropping event with dtend=$end < dtstart=$begin")
+
+    // Recurring events store DURATION instead of DTEND, so the series row's
+    // DTEND is null. Keep the event (end == begin); callers that opened a
+    // specific occurrence supply the real per-occurrence times from
+    // CalendarContract.Instances. Only a present-but-backwards DTEND is malformed.
+    val end = if (isNull(EventDetailProjection.IDX_DTEND)) {
+        begin
+    } else {
+        val rawEnd = getLong(EventDetailProjection.IDX_DTEND)
+        if (rawEnd < begin) {
+            Log.w(TAG, "Dropping event with dtend=$rawEnd < dtstart=$begin")
             return null
         }
+        rawEnd
+    }
 
-    val rawTitle = getString(EventDetailProjection.IDX_TITLE)
-    val title = if (rawTitle.isNullOrEmpty()) Fallbacks.UNTITLED_EVENT else rawTitle
+    // Kept raw (no untitled fallback): the detail screen substitutes its own
+    // localized placeholder, and the edit form must prefill the true value.
+    val title = getString(EventDetailProjection.IDX_TITLE).orEmpty()
 
-    val color = if (isNull(EventDetailProjection.IDX_EVENT_COLOR)) {
-        getInt(EventDetailProjection.IDX_CALENDAR_COLOR)
+    // The event's own colour (null = inherits the calendar's) is kept apart
+    // from the resolved display colour: the edit form needs to tell the two
+    // cases apart, while the instance carries the calendar fallback for display.
+    val eventColor = if (isNull(EventDetailProjection.IDX_EVENT_COLOR)) {
+        null
     } else {
         getInt(EventDetailProjection.IDX_EVENT_COLOR)
     }
+    val eventColorKey = getString(EventDetailProjection.IDX_EVENT_COLOR_KEY)
+    val color = eventColor ?: getInt(EventDetailProjection.IDX_CALENDAR_COLOR)
 
     val eventId = getLong(EventDetailProjection.IDX_EVENT_ID)
+    val isAllDay = getInt(EventDetailProjection.IDX_ALL_DAY) != 0
     val instance = EventInstance(
         instanceId = eventId,
         eventId = eventId,
@@ -39,17 +69,47 @@ internal fun ColumnReader.toEventDetailCore(attendees: List<Attendee>): EventDet
         title = title,
         start = begin.toKotlinInstantFromEpochMillis(),
         end = end.toKotlinInstantFromEpochMillis(),
-        isAllDay = getInt(EventDetailProjection.IDX_ALL_DAY) != 0,
+        isAllDay = isAllDay,
         color = color,
         location = getString(EventDetailProjection.IDX_LOCATION),
     )
 
+    // All-day reminders are stored as a wall-clock-shifted offset (see
+    // AllDayReminderEncoding); decode back to the whole-day lead time the form
+    // and detail screen speak. DTSTART is UTC midnight for all-day events, so the
+    // event's date is its UTC date.
+    val displayReminders = if (isAllDay) {
+        val startDate = Instant.ofEpochMilli(begin).atZone(ZoneOffset.UTC).toLocalDate()
+        val zone = ZoneId.systemDefault()
+        reminders.map { it.copy(minutes = fromProviderAllDayMinutes(it.minutes, startDate, zone)) }
+    } else {
+        reminders
+    }
+
+    // STATUS shares its 0 value with STATUS_TENTATIVE, so a missing column must
+    // be distinguished from a present 0 — an absent status means "just confirmed".
+    val status = if (isNull(EventDetailProjection.IDX_STATUS)) {
+        EventStatus.Confirmed
+    } else {
+        mapEventStatus(getInt(EventDetailProjection.IDX_STATUS))
+    }
+
     return EventDetail(
         instance = instance,
         description = getString(EventDetailProjection.IDX_DESCRIPTION),
         organizer = getString(EventDetailProjection.IDX_ORGANIZER),
         attendees = attendees,
         rrule = getString(EventDetailProjection.IDX_RRULE),
+        reminders = displayReminders,
+        status = status,
+        // BUSY and DEFAULT are both 0, so a null column folds into the same
+        // default these mappers already return — no isNull guard needed.
+        availability = mapAvailability(getInt(EventDetailProjection.IDX_AVAILABILITY)),
+        accessLevel = mapAccessLevel(getInt(EventDetailProjection.IDX_ACCESS_LEVEL)),
+        eventTimezone = getString(EventDetailProjection.IDX_EVENT_TIMEZONE),
+        selfStatus = mapAttendeeStatus(getInt(EventDetailProjection.IDX_SELF_ATTENDEE_STATUS)),
+        eventColor = eventColor,
+        eventColorKey = eventColorKey,
     )
 }
 
@@ -57,6 +117,13 @@ internal fun ColumnReader.toAttendee(): Attendee = Attendee(
     name = getString(AttendeeProjection.IDX_NAME).orEmpty(),
     email = getString(AttendeeProjection.IDX_EMAIL),
     status = mapAttendeeStatus(getInt(AttendeeProjection.IDX_STATUS)),
+    relationship = mapAttendeeRelationship(getInt(AttendeeProjection.IDX_RELATIONSHIP)),
+    type = mapAttendeeType(getInt(AttendeeProjection.IDX_TYPE)),
+)
+
+internal fun ColumnReader.toReminder(): Reminder = Reminder(
+    minutes = getInt(ReminderProjection.IDX_MINUTES),
+    method = mapReminderMethod(getInt(ReminderProjection.IDX_METHOD)),
 )
 
 internal fun mapAttendeeStatus(raw: Int): AttendeeStatus = when (raw) {
@@ -66,3 +133,46 @@ internal fun mapAttendeeStatus(raw: Int): AttendeeStatus = when (raw) {
     CalendarContract.Attendees.ATTENDEE_STATUS_INVITED -> AttendeeStatus.NeedsAction
     else -> AttendeeStatus.Unknown
 }
+
+internal fun mapAttendeeRelationship(raw: Int): AttendeeRelationship = when (raw) {
+    CalendarContract.Attendees.RELATIONSHIP_ORGANIZER -> AttendeeRelationship.Organizer
+    CalendarContract.Attendees.RELATIONSHIP_PERFORMER -> AttendeeRelationship.Performer
+    CalendarContract.Attendees.RELATIONSHIP_SPEAKER -> AttendeeRelationship.Speaker
+    CalendarContract.Attendees.RELATIONSHIP_ATTENDEE -> AttendeeRelationship.Attendee
+    else -> AttendeeRelationship.None
+}
+
+internal fun mapAttendeeType(raw: Int): AttendeeType = when (raw) {
+    CalendarContract.Attendees.TYPE_REQUIRED -> AttendeeType.Required
+    CalendarContract.Attendees.TYPE_OPTIONAL -> AttendeeType.Optional
+    CalendarContract.Attendees.TYPE_RESOURCE -> AttendeeType.Resource
+    else -> AttendeeType.None
+}
+
+internal fun mapEventStatus(raw: Int): EventStatus = when (raw) {
+    CalendarContract.Events.STATUS_CONFIRMED -> EventStatus.Confirmed
+    CalendarContract.Events.STATUS_TENTATIVE -> EventStatus.Tentative
+    CalendarContract.Events.STATUS_CANCELED -> EventStatus.Cancelled
+    else -> EventStatus.Confirmed
+}
+
+internal fun mapAvailability(raw: Int): Availability = when (raw) {
+    CalendarContract.Events.AVAILABILITY_FREE -> Availability.Free
+    CalendarContract.Events.AVAILABILITY_TENTATIVE -> Availability.Tentative
+    else -> Availability.Busy
+}
+
+internal fun mapAccessLevel(raw: Int): AccessLevel = when (raw) {
+    CalendarContract.Events.ACCESS_CONFIDENTIAL -> AccessLevel.Confidential
+    CalendarContract.Events.ACCESS_PRIVATE -> AccessLevel.Private
+    CalendarContract.Events.ACCESS_PUBLIC -> AccessLevel.Public
+    else -> AccessLevel.Default
+}
+
+internal fun mapReminderMethod(raw: Int): ReminderMethod = when (raw) {
+    CalendarContract.Reminders.METHOD_EMAIL -> ReminderMethod.Email
+    CalendarContract.Reminders.METHOD_SMS -> ReminderMethod.Sms
+    CalendarContract.Reminders.METHOD_ALARM -> ReminderMethod.Alarm
+    CalendarContract.Reminders.METHOD_ALERT -> ReminderMethod.Alert
+    else -> ReminderMethod.Default
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/EventWriteMapper.kt

@@ -0,0 +1,189 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import android.provider.CalendarContract
+import de.jeanlucmakiola.calendula.domain.AccessLevel
+import de.jeanlucmakiola.calendula.domain.Availability
+import de.jeanlucmakiola.calendula.domain.EventForm
+import kotlinx.datetime.toJavaLocalDate
+import kotlinx.datetime.toJavaLocalDateTime
+import java.time.Instant
+import java.time.ZoneId
+import java.time.ZoneOffset
+
+/** Provider-ready DTSTART / DTEND / EVENT_TIMEZONE for an event write. */
+internal data class EventWriteTimes(
+    val dtStartMillis: Long,
+    val dtEndMillis: Long,
+    val timezone: String,
+)
+
+/**
+ * All-day events live at UTC midnights with an exclusive DTEND (the
+ * CalendarContract convention — a one-day event ends at the next midnight);
+ * timed events resolve their wall-clock values in [zone].
+ */
+internal fun EventForm.toWriteTimes(zone: ZoneId): EventWriteTimes = if (isAllDay) {
+    EventWriteTimes(
+        dtStartMillis = start.date.toJavaLocalDate()
+            .atStartOfDay(ZoneOffset.UTC).toInstant().toEpochMilli(),
+        dtEndMillis = end.date.toJavaLocalDate().plusDays(1)
+            .atStartOfDay(ZoneOffset.UTC).toInstant().toEpochMilli(),
+        timezone = "UTC",
+    )
+} else {
+    EventWriteTimes(
+        dtStartMillis = start.toJavaLocalDateTime().atZone(zone).toInstant().toEpochMilli(),
+        dtEndMillis = end.toJavaLocalDateTime().atZone(zone).toInstant().toEpochMilli(),
+        timezone = zone.id,
+    )
+}
+
+/**
+ * RFC 2445 duration for a recurring event's row (the provider requires
+ * DURATION instead of DTEND when an RRULE is set): whole days for all-day
+ * events, seconds otherwise.
+ */
+internal fun EventWriteTimes.toRfc2445Duration(isAllDay: Boolean): String = if (isAllDay) {
+    "P${(dtEndMillis - dtStartMillis) / MILLIS_PER_DAY}D"
+} else {
+    "P${(dtEndMillis - dtStartMillis) / 1_000L}S"
+}
+
+/**
+ * Dirty-checked column values for updating an existing Events row: only what
+ * the user actually changed is written, so untouched fields can't stomp
+ * concurrent external edits. Keys are `CalendarContract.Events` columns; a
+ * null value means "set the column to NULL". An empty map means nothing on
+ * the row changed.
+ *
+ * Time fields travel together (the provider validates them as a unit):
+ * - unchanged times, all-day flag and rrule → no time columns at all;
+ * - non-recurring result → DTSTART/DTEND, DURATION and RRULE cleared;
+ * - recurring result → the *series* DTSTART moves by the same delta the user
+ *   applied to the displayed occurrence ([seriesDtStartMillis] is the row's
+ *   current DTSTART), DURATION replaces DTEND, RRULE is written. This keeps
+ *   past occurrences intact when someone edits a later occurrence's time.
+ */
+internal fun buildEventUpdateValues(
+    original: EventForm,
+    updated: EventForm,
+    seriesDtStartMillis: Long,
+    zone: ZoneId,
+): Map<String, Any?> = buildMap {
+    if (updated.title.trim() != original.title.trim()) {
+        put(CalendarContract.Events.TITLE, updated.title.trim())
+    }
+    if (updated.location.trim() != original.location.trim()) {
+        put(CalendarContract.Events.EVENT_LOCATION, updated.location.trim().ifEmpty { null })
+    }
+    if (updated.description.trim() != original.description.trim()) {
+        put(CalendarContract.Events.DESCRIPTION, updated.description.trim().ifEmpty { null })
+    }
+    if (updated.availability != original.availability) {
+        put(CalendarContract.Events.AVAILABILITY, updated.availability.toProviderValue())
+    }
+    if (updated.accessLevel != original.accessLevel) {
+        put(CalendarContract.Events.ACCESS_LEVEL, updated.accessLevel.toProviderValue())
+    }
+    if (updated.colorKey != original.colorKey || updated.color != original.color) {
+        putAll(eventColorColumns(updated.colorKey, updated.color))
+    }
+
+    val timesChanged = updated.start != original.start ||
+        updated.end != original.end ||
+        updated.isAllDay != original.isAllDay ||
+        updated.rrule != original.rrule
+    if (!timesChanged) return@buildMap
+
+    val newTimes = updated.toWriteTimes(zone)
+    put(CalendarContract.Events.ALL_DAY, if (updated.isAllDay) 1 else 0)
+    put(CalendarContract.Events.EVENT_TIMEZONE, newTimes.timezone)
+    if (updated.rrule == null) {
+        put(CalendarContract.Events.DTSTART, newTimes.dtStartMillis)
+        put(CalendarContract.Events.DTEND, newTimes.dtEndMillis)
+        put(CalendarContract.Events.RRULE, null)
+        put(CalendarContract.Events.DURATION, null)
+    } else {
+        val startDelta = newTimes.dtStartMillis - original.toWriteTimes(zone).dtStartMillis
+        put(CalendarContract.Events.DTSTART, seriesDtStartMillis + startDelta)
+        put(CalendarContract.Events.DTEND, null)
+        put(CalendarContract.Events.RRULE, updated.rrule)
+        put(CalendarContract.Events.DURATION, newTimes.toRfc2445Duration(updated.isAllDay))
+    }
+}
+
+/**
+ * Column values for a modified-occurrence exception row ("edit only this
+ * event"): inserting them at `Events.CONTENT_EXCEPTION_URI/<id>` makes the
+ * provider clone the series row and apply these on top. Unlike the series
+ * update there is no dirty check — the exception is a fresh row, so every
+ * form-backed column is written (empty optionals as explicit NULLs, since the
+ * clone starts from the parent's values). An exception is a single event:
+ * DTEND, never RRULE/DURATION.
+ */
+internal fun buildOccurrenceExceptionValues(
+    form: EventForm,
+    originalInstanceMillis: Long,
+    zone: ZoneId,
+): Map<String, Any?> = buildMap {
+    val times = form.toWriteTimes(zone)
+    put(CalendarContract.Events.ORIGINAL_INSTANCE_TIME, originalInstanceMillis)
+    put(CalendarContract.Events.TITLE, form.title.trim())
+    put(CalendarContract.Events.ALL_DAY, if (form.isAllDay) 1 else 0)
+    put(CalendarContract.Events.DTSTART, times.dtStartMillis)
+    put(CalendarContract.Events.DTEND, times.dtEndMillis)
+    put(CalendarContract.Events.EVENT_TIMEZONE, times.timezone)
+    put(CalendarContract.Events.AVAILABILITY, form.availability.toProviderValue())
+    put(CalendarContract.Events.ACCESS_LEVEL, form.accessLevel.toProviderValue())
+    put(CalendarContract.Events.EVENT_LOCATION, form.location.trim().ifEmpty { null })
+    put(CalendarContract.Events.DESCRIPTION, form.description.trim().ifEmpty { null })
+    putAll(eventColorColumns(form.colorKey, form.color))
+}
+
+/**
+ * The `EVENT_COLOR` / `EVENT_COLOR_KEY` columns for a colour selection. A
+ * [colorKey] writes the key alone (the provider derives `EVENT_COLOR` from the
+ * account's palette, so the colour round-trips through sync); a raw [color]
+ * writes `EVENT_COLOR` and clears any key; "no colour" clears both so the event
+ * falls back to its calendar's colour. The two are never written together —
+ * the provider rejects a raw colour on a calendar that publishes a palette,
+ * which is exactly why palette calendars only ever go through the key.
+ */
+internal fun eventColorColumns(colorKey: String?, color: Int?): Map<String, Any?> = when {
+    colorKey != null -> mapOf(CalendarContract.Events.EVENT_COLOR_KEY to colorKey)
+    color != null -> mapOf(
+        CalendarContract.Events.EVENT_COLOR_KEY to null,
+        CalendarContract.Events.EVENT_COLOR to color,
+    )
+    else -> mapOf(
+        CalendarContract.Events.EVENT_COLOR_KEY to null,
+        CalendarContract.Events.EVENT_COLOR to null,
+    )
+}
+
+/**
+ * UTC millis of the last second of the local day *before* the occurrence at
+ * [beginMillis] in [zone] — the cutoff for truncating a series with UNTIL.
+ * The provider's recurrence engine applies UNTIL coarsely (observed on a
+ * Pixel: an occurrence one second *after* UNTIL was still generated), so the
+ * series must end on the previous day, not one second before the occurrence.
+ * With no sub-daily frequencies that is semantically the same cut.
+ */
+internal fun previousLocalDayEndUtcMillis(beginMillis: Long, zone: ZoneId): Long =
+    Instant.ofEpochMilli(beginMillis).atZone(zone).toLocalDate()
+        .atStartOfDay(zone).toInstant().toEpochMilli() - 1_000L
+
+private const val MILLIS_PER_DAY = 86_400_000L
+
+internal fun Availability.toProviderValue(): Int = when (this) {
+    Availability.Busy -> CalendarContract.Events.AVAILABILITY_BUSY
+    Availability.Free -> CalendarContract.Events.AVAILABILITY_FREE
+    Availability.Tentative -> CalendarContract.Events.AVAILABILITY_TENTATIVE
+}
+
+internal fun AccessLevel.toProviderValue(): Int = when (this) {
+    AccessLevel.Default -> CalendarContract.Events.ACCESS_DEFAULT
+    AccessLevel.Confidential -> CalendarContract.Events.ACCESS_CONFIDENTIAL
+    AccessLevel.Private -> CalendarContract.Events.ACCESS_PRIVATE
+    AccessLevel.Public -> CalendarContract.Events.ACCESS_PUBLIC
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/IcsExportMapper.kt

@@ -0,0 +1,54 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import de.jeanlucmakiola.calendula.domain.EventStatus
+import de.jeanlucmakiola.calendula.domain.ics.IcsEvent
+import de.jeanlucmakiola.calendula.domain.ics.deriveIcsUid
+import de.jeanlucmakiola.calendula.domain.ics.parseRfc2445DurationMillis
+
+/**
+ * Map one Events row (read through [EventExportProjection]) into an [IcsEvent]
+ * for backup. [reminderMinutes] are the row's raw provider reminder offsets and
+ * [calendarName] the display name of its calendar (emitted as
+ * `X-CALENDULA-CALENDAR`). Pure given a [ColumnReader] — JVM-tested with
+ * MapColumnReader.
+ */
+internal fun ColumnReader.toIcsEvent(
+    reminderMinutes: List<Int>,
+    calendarName: String?,
+): IcsEvent {
+    val eventId = getLong(EventExportProjection.IDX_ID)
+    val dtStart = getLong(EventExportProjection.IDX_DTSTART)
+    val rrule = getString(EventExportProjection.IDX_RRULE)?.takeIf { it.isNotBlank() }
+
+    // Recurring rows store DURATION instead of DTEND; reconstruct the end from it
+    // so the writer can render DTEND. A missing/blank both means a zero-length event.
+    val end = when {
+        !isNull(EventExportProjection.IDX_DTEND) -> getLong(EventExportProjection.IDX_DTEND)
+        else -> dtStart + parseRfc2445DurationMillis(getString(EventExportProjection.IDX_DURATION))
+    }
+
+    // STATUS shares value 0 with TENTATIVE, so an absent column must read as Confirmed.
+    val status = if (isNull(EventExportProjection.IDX_STATUS)) {
+        EventStatus.Confirmed
+    } else {
+        mapEventStatus(getInt(EventExportProjection.IDX_STATUS))
+    }
+
+    return IcsEvent(
+        uid = deriveIcsUid(getString(EventExportProjection.IDX_UID), eventId, dtStart),
+        summary = getString(EventExportProjection.IDX_TITLE).orEmpty(),
+        start = dtStart.toKotlinInstantFromEpochMillis(),
+        end = end.toKotlinInstantFromEpochMillis(),
+        isAllDay = getInt(EventExportProjection.IDX_ALL_DAY) != 0,
+        zoneId = getString(EventExportProjection.IDX_EVENT_TIMEZONE)?.takeIf { it.isNotBlank() }
+            ?: "UTC",
+        recurrenceRule = rrule,
+        location = getString(EventExportProjection.IDX_LOCATION),
+        description = getString(EventExportProjection.IDX_DESCRIPTION),
+        reminderMinutes = reminderMinutes,
+        status = status,
+        availability = mapAvailability(getInt(EventExportProjection.IDX_AVAILABILITY)),
+        calendarName = calendarName,
+    )
+}
+

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/Projections.kt

@@ -10,14 +10,23 @@ internal object CalendarProjection {
         CalendarContract.Calendars.ACCOUNT_TYPE,
         CalendarContract.Calendars.CALENDAR_COLOR,
         CalendarContract.Calendars.VISIBLE,
+        CalendarContract.Calendars.CALENDAR_ACCESS_LEVEL,
+        // CalendarContract has no description column; for the local calendars we
+        // own we stash one in CAL_SYNC1 (synced rows put their sync token here,
+        // so the mapper only reads it for local calendars).
+        DESCRIPTION_COLUMN,
     )
 
+    const val DESCRIPTION_COLUMN: String = CalendarContract.Calendars.CAL_SYNC1
+
     const val IDX_ID = 0
     const val IDX_DISPLAY_NAME = 1
     const val IDX_ACCOUNT_NAME = 2
     const val IDX_ACCOUNT_TYPE = 3
     const val IDX_COLOR = 4
     const val IDX_VISIBLE = 5
+    const val IDX_ACCESS_LEVEL = 6
+    const val IDX_DESCRIPTION = 7
 }
 
 internal object InstanceProjection {
@@ -60,6 +69,12 @@ internal object EventDetailProjection {
         CalendarContract.Events.ALL_DAY,
         CalendarContract.Events.EVENT_LOCATION,
         CalendarContract.Events.CALENDAR_ID,
+        CalendarContract.Events.STATUS,
+        CalendarContract.Events.AVAILABILITY,
+        CalendarContract.Events.ACCESS_LEVEL,
+        CalendarContract.Events.EVENT_TIMEZONE,
+        CalendarContract.Events.SELF_ATTENDEE_STATUS,
+        CalendarContract.Events.EVENT_COLOR_KEY,
     )
 
     const val IDX_EVENT_ID = 0
@@ -74,6 +89,54 @@ internal object EventDetailProjection {
     const val IDX_ALL_DAY = 9
     const val IDX_LOCATION = 10
     const val IDX_CALENDAR_ID = 11
+    const val IDX_STATUS = 12
+    const val IDX_AVAILABILITY = 13
+    const val IDX_ACCESS_LEVEL = 14
+    const val IDX_EVENT_TIMEZONE = 15
+    const val IDX_SELF_ATTENDEE_STATUS = 16
+    const val IDX_EVENT_COLOR_KEY = 17
+}
+
+/**
+ * Master/one-off Events rows for a whole-calendar backup. Unlike
+ * [EventDetailProjection] this reads `UID_2445` (to keep a row's identity across
+ * backups) and `DURATION` (recurring rows carry it instead of DTEND). Modified-
+ * occurrence and cancelled-exception rows are filtered out by the query
+ * (`ORIGINAL_ID IS NULL`), so RECURRENCE-ID overrides and EXDATEs aren't
+ * exported yet — a documented v1 limit (import skips them too).
+ */
+internal object EventExportProjection {
+    val COLUMNS: Array<String> = arrayOf(
+        CalendarContract.Events._ID,
+        CalendarContract.Events.UID_2445,
+        CalendarContract.Events.TITLE,
+        CalendarContract.Events.DTSTART,
+        CalendarContract.Events.DTEND,
+        CalendarContract.Events.DURATION,
+        CalendarContract.Events.ALL_DAY,
+        CalendarContract.Events.EVENT_TIMEZONE,
+        CalendarContract.Events.RRULE,
+        CalendarContract.Events.EVENT_LOCATION,
+        CalendarContract.Events.DESCRIPTION,
+        CalendarContract.Events.STATUS,
+        CalendarContract.Events.AVAILABILITY,
+        CalendarContract.Events.CALENDAR_ID,
+    )
+
+    const val IDX_ID = 0
+    const val IDX_UID = 1
+    const val IDX_TITLE = 2
+    const val IDX_DTSTART = 3
+    const val IDX_DTEND = 4
+    const val IDX_DURATION = 5
+    const val IDX_ALL_DAY = 6
+    const val IDX_EVENT_TIMEZONE = 7
+    const val IDX_RRULE = 8
+    const val IDX_LOCATION = 9
+    const val IDX_DESCRIPTION = 10
+    const val IDX_STATUS = 11
+    const val IDX_AVAILABILITY = 12
+    const val IDX_CALENDAR_ID = 13
 }
 
 internal object AttendeeProjection {
@@ -81,11 +144,25 @@ internal object AttendeeProjection {
         CalendarContract.Attendees.ATTENDEE_NAME,
         CalendarContract.Attendees.ATTENDEE_EMAIL,
         CalendarContract.Attendees.ATTENDEE_STATUS,
+        CalendarContract.Attendees.ATTENDEE_RELATIONSHIP,
+        CalendarContract.Attendees.ATTENDEE_TYPE,
     )
 
     const val IDX_NAME = 0
     const val IDX_EMAIL = 1
     const val IDX_STATUS = 2
+    const val IDX_RELATIONSHIP = 3
+    const val IDX_TYPE = 4
+}
+
+internal object ReminderProjection {
+    val COLUMNS: Array<String> = arrayOf(
+        CalendarContract.Reminders.MINUTES,
+        CalendarContract.Reminders.METHOD,
+    )
+
+    const val IDX_MINUTES = 0
+    const val IDX_METHOD = 1
 }
 
 internal object Fallbacks {

app/src/main/java/de/jeanlucmakiola/calendula/data/di/DataModule.kt

@@ -14,6 +14,8 @@ import de.jeanlucmakiola.calendula.data.calendar.AndroidCalendarDataSource
 import de.jeanlucmakiola.calendula.data.calendar.CalendarDataSource
 import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
 import de.jeanlucmakiola.calendula.data.calendar.CalendarRepositoryImpl
+import de.jeanlucmakiola.calendula.data.reminders.AndroidReminderAlertStore
+import de.jeanlucmakiola.calendula.data.reminders.ReminderAlertStore
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.Dispatchers
 import javax.inject.Singleton
@@ -37,6 +39,12 @@ abstract class DataBindModule {
     abstract fun bindCalendarRepository(
         impl: CalendarRepositoryImpl,
     ): CalendarRepository
+
+    @Binds
+    @Singleton
+    abstract fun bindReminderAlertStore(
+        impl: AndroidReminderAlertStore,
+    ): ReminderAlertStore
 }
 
 @Module

app/src/main/java/de/jeanlucmakiola/calendula/data/ics/IcsExporter.kt

@@ -0,0 +1,45 @@
+package de.jeanlucmakiola.calendula.data.ics
+
+import android.content.Context
+import android.net.Uri
+import androidx.core.content.FileProvider
+import dagger.hilt.android.qualifiers.ApplicationContext
+import java.io.File
+import java.io.IOException
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * The Android IO edge of `.ics` export: writes a serialised calendar to a
+ * SAF document (whole-calendar backup) or stages it in a cache file behind a
+ * `FileProvider` content Uri (single-event share). The serialisation itself is
+ * the pure `domain.ics.IcsWriter`; this class only moves bytes.
+ */
+@Singleton
+class IcsExporter @Inject constructor(
+    @ApplicationContext private val context: Context,
+) {
+
+    /** Write [content] to the SAF document at [uri] as UTF-8. Throws on failure. */
+    fun writeDocument(uri: Uri, content: String) {
+        context.contentResolver.openOutputStream(uri)?.use { out ->
+            out.write(content.toByteArray(Charsets.UTF_8))
+        } ?: throw IOException("Could not open $uri for writing")
+    }
+
+    /**
+     * Stage [content] in a private cache file and return a shareable content
+     * Uri for an `ACTION_SEND`. [fileName] is the suggested `.ics` name shown to
+     * the receiving app. The authority mirrors the manifest's `FileProvider`.
+     */
+    fun stageShareFile(fileName: String, content: String): Uri {
+        val dir = File(context.cacheDir, SHARE_DIR).apply { mkdirs() }
+        val file = File(dir, fileName)
+        file.writeText(content, Charsets.UTF_8)
+        return FileProvider.getUriForFile(context, "${context.packageName}.fileprovider", file)
+    }
+
+    private companion object {
+        const val SHARE_DIR = "shared_ics"
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/ics/IcsImporter.kt

@@ -0,0 +1,21 @@
+package de.jeanlucmakiola.calendula.data.ics
+
+import android.content.Context
+import android.net.Uri
+import dagger.hilt.android.qualifiers.ApplicationContext
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Android IO edge of `.ics` import: reads the text of a received/opened
+ * document [Uri]. Parsing is the pure `domain.ics.IcsParser`; this class only
+ * pulls bytes off the ContentResolver. Returns null on any read failure.
+ */
+@Singleton
+class IcsImporter @Inject constructor(
+    @ApplicationContext private val context: Context,
+) {
+    fun readText(uri: Uri): String? = runCatching {
+        context.contentResolver.openInputStream(uri)?.use { it.readBytes().toString(Charsets.UTF_8) }
+    }.getOrNull()
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/prefs/CalendarPrefs.kt

@@ -3,6 +3,7 @@ package de.jeanlucmakiola.calendula.data.prefs
 import androidx.datastore.core.DataStore
 import androidx.datastore.preferences.core.Preferences
 import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.longPreferencesKey
 import androidx.datastore.preferences.core.stringPreferencesKey
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.map
@@ -38,7 +39,20 @@ class CalendarPrefs @Inject constructor(
         }
     }
 
+    /**
+     * The calendar the user last created an event in; preselected in the
+     * event form. Null until the first event is created.
+     */
+    val lastUsedCalendarId: Flow<Long?> = store.data.map { prefs ->
+        prefs[LAST_USED_CALENDAR_KEY]
+    }
+
+    suspend fun setLastUsedCalendarId(id: Long) {
+        store.edit { prefs -> prefs[LAST_USED_CALENDAR_KEY] = id }
+    }
+
     companion object {
         internal val HIDDEN_IDS_KEY = stringPreferencesKey("hidden_calendar_ids")
+        internal val LAST_USED_CALENDAR_KEY = longPreferencesKey("last_used_calendar_id")
     }
 }

app/src/main/java/de/jeanlucmakiola/calendula/data/prefs/SettingsPrefs.kt

@@ -0,0 +1,324 @@
+package de.jeanlucmakiola.calendula.data.prefs
+
+import androidx.datastore.core.DataStore
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.core.booleanPreferencesKey
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.core.intPreferencesKey
+import androidx.datastore.preferences.core.stringPreferencesKey
+import de.jeanlucmakiola.calendula.domain.EventFormField
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.map
+import kotlinx.datetime.DayOfWeek
+import java.time.temporal.WeekFields
+import java.util.Locale
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/** Light/dark override. SYSTEM follows the device setting. */
+enum class ThemeMode { SYSTEM, LIGHT, DARK }
+
+/** Week-start override. AUTO derives the first day from the active locale. */
+enum class WeekStartPref { AUTO, MONDAY, SUNDAY }
+
+/**
+ * Resolve the preference to a concrete first-day-of-week. AUTO reads the
+ * locale's convention (e.g. Monday in DE, Sunday in en-US).
+ */
+fun WeekStartPref.resolveFirstDay(locale: Locale): DayOfWeek = when (this) {
+    WeekStartPref.MONDAY -> DayOfWeek.MONDAY
+    WeekStartPref.SUNDAY -> DayOfWeek.SUNDAY
+    // java.time.DayOfWeek.value is ISO 1..7 (Mon..Sun) — same numbering kotlinx uses.
+    WeekStartPref.AUTO -> DayOfWeek(WeekFields.of(locale).firstDayOfWeek.value)
+}
+
+/**
+ * Display settings (M4) persisted app-side: theme override, Material You
+ * dynamic colour, and week start. Language is handled separately through
+ * AppCompatDelegate (which persists its own per-app locale).
+ *
+ * Enum prefs round-trip by [Enum.name]; an unknown/garbage stored value falls
+ * back to the default rather than throwing (see SettingsPrefsTest).
+ */
+@Singleton
+class SettingsPrefs @Inject constructor(
+    private val store: DataStore<Preferences>,
+) {
+
+    val themeMode: Flow<ThemeMode> = store.data.map { prefs ->
+        prefs[THEME_MODE_KEY].toEnum(ThemeMode.SYSTEM)
+    }
+
+    val dynamicColor: Flow<Boolean> = store.data.map { prefs ->
+        prefs[DYNAMIC_COLOR_KEY] ?: true
+    }
+
+    val weekStart: Flow<WeekStartPref> = store.data.map { prefs ->
+        prefs[WEEK_START_KEY].toEnum(WeekStartPref.AUTO)
+    }
+
+    suspend fun setThemeMode(mode: ThemeMode) {
+        store.edit { it[THEME_MODE_KEY] = mode.name }
+    }
+
+    suspend fun setDynamicColor(enabled: Boolean) {
+        store.edit { it[DYNAMIC_COLOR_KEY] = enabled }
+    }
+
+    suspend fun setWeekStart(pref: WeekStartPref) {
+        store.edit { it[WEEK_START_KEY] = pref.name }
+    }
+
+    /**
+     * Optional event-form fields shown by default (the rest hide behind
+     * "more fields"). Stored comma-joined by enum name: an absent key means
+     * the factory default, an empty string means "none". Unknown names are
+     * dropped defensively, like the other enum prefs.
+     */
+    val defaultFormFields: Flow<Set<EventFormField>> = store.data.map { prefs ->
+        parseFormFields(prefs[FORM_FIELDS_KEY])
+    }
+
+    suspend fun setFormFieldDefault(field: EventFormField, enabled: Boolean) {
+        store.edit { prefs ->
+            val current = parseFormFields(prefs[FORM_FIELDS_KEY])
+            val updated = if (enabled) current + field else current - field
+            prefs[FORM_FIELDS_KEY] = updated.joinToString(",") { it.name }
+        }
+    }
+
+    /**
+     * Whether Calendula posts reminder notifications (v1.4). Defaults to ON —
+     * for users whose only calendar app this is, reminders are essential; the
+     * onboarding step and Settings warn about duplicates from a second app.
+     */
+    val remindersEnabled: Flow<Boolean> = store.data.map { prefs ->
+        prefs[REMINDERS_ENABLED_KEY] ?: true
+    }
+
+    suspend fun setRemindersEnabled(enabled: Boolean) {
+        store.edit { it[REMINDERS_ENABLED_KEY] = enabled }
+    }
+
+    /**
+     * Whether to offer a custom event colour even on calendars that publish no
+     * colour palette (most local calendars handle it fine; synced calendars
+     * without a palette — some CalDAV — may drop or overwrite a raw colour on
+     * their next sync). Defaults to OFF: such calendars hide the colour picker
+     * until the user opts in, accepting the limitation. Local calendars and
+     * palette-backed calendars (Google, …) are unaffected by this flag.
+     */
+    val allowColorOnUnsupportedCalendars: Flow<Boolean> = store.data.map { prefs ->
+        prefs[ALLOW_COLOR_UNSUPPORTED_KEY] ?: false
+    }
+
+    suspend fun setAllowColorOnUnsupportedCalendars(enabled: Boolean) {
+        store.edit { it[ALLOW_COLOR_UNSUPPORTED_KEY] = enabled }
+    }
+
+    /**
+     * Whether the one-time reminder onboarding step (after the calendar
+     * grant) has been shown — also true for users who tapped "not now".
+     */
+    val reminderOnboardingDone: Flow<Boolean> = store.data.map { prefs ->
+        prefs[REMINDER_ONBOARDING_KEY] ?: false
+    }
+
+    suspend fun setReminderOnboardingDone() {
+        store.edit { it[REMINDER_ONBOARDING_KEY] = true }
+    }
+
+    /**
+     * The default reminder lead time (minutes before start) prefilled on new
+     * **timed** events. `null` = no default reminder — the prior behaviour, kept
+     * as the factory default so existing users aren't surprised by reminders they
+     * never asked for. Stored as a string so "none" is distinct from a numeric
+     * value (and from an unset key, which is also "none"). Per-calendar overrides
+     * in [perCalendarReminderOverride] take precedence; all-day events instead use
+     * [defaultAllDayReminderMinutes]. Resolve with [resolveDefaultReminder].
+     */
+    val defaultReminderMinutes: Flow<Int?> = store.data.map { prefs ->
+        prefs[DEFAULT_REMINDER_KEY].toReminderMinutes()
+    }
+
+    suspend fun setDefaultReminderMinutes(minutes: Int?) {
+        store.edit { it[DEFAULT_REMINDER_KEY] = minutes?.toString() ?: NONE }
+    }
+
+    /**
+     * The default reminder lead time prefilled on new **all-day** events, in
+     * minutes before the start of the day. All-day events want day-scale lead
+     * times ("1 day before"), so they have their own default rather than reusing
+     * the timed one. `null` = no default. Per-calendar overrides do **not** apply
+     * to all-day events — they always use this global value.
+     */
+    val defaultAllDayReminderMinutes: Flow<Int?> = store.data.map { prefs ->
+        prefs[DEFAULT_ALLDAY_REMINDER_KEY].toReminderMinutes()
+    }
+
+    suspend fun setDefaultAllDayReminderMinutes(minutes: Int?) {
+        store.edit { it[DEFAULT_ALLDAY_REMINDER_KEY] = minutes?.toString() ?: NONE }
+    }
+
+    /**
+     * Wall-clock time, as minutes from local midnight, at which **all-day**
+     * reminders fire. All-day events live at UTC midnight, so a raw "1 day
+     * before" would fire at an off hour (02:00 local in CEST); this time is
+     * encoded into the provider offset so the reminder lands at, e.g., 09:00 the
+     * day before instead. Global for every all-day reminder; default 09:00.
+     * Stored/clamped to a valid 0..1439 minute-of-day.
+     */
+    val allDayReminderTimeMinutes: Flow<Int> = store.data.map { prefs ->
+        (prefs[ALLDAY_REMINDER_TIME_KEY] ?: DEFAULT_ALLDAY_REMINDER_TIME)
+            .coerceIn(0, MINUTES_PER_DAY - 1)
+    }
+
+    suspend fun setAllDayReminderTimeMinutes(minutesOfDay: Int) {
+        store.edit { it[ALLDAY_REMINDER_TIME_KEY] = minutesOfDay.coerceIn(0, MINUTES_PER_DAY - 1) }
+    }
+
+    /**
+     * Per-calendar overrides of [defaultReminderMinutes] for **timed** events,
+     * keyed by calendar id. A calendar **present** in the map overrides the global
+     * timed default for its new events: a `null` value means "no reminder", an int
+     * means that lead time. A calendar **absent** from the map inherits the global
+     * default. Serialised as `id=value;id=value`, with `none` for an explicit
+     * no-reminder override. (All-day events ignore this and use
+     * [defaultAllDayReminderMinutes].)
+     */
+    val perCalendarReminderOverride: Flow<Map<Long, Int?>> = store.data.map { prefs ->
+        parseReminderOverrides(prefs[CALENDAR_REMINDER_OVERRIDE_KEY])
+    }
+
+    suspend fun setCalendarReminderOverride(calendarId: Long, override: CalendarReminderOverride) {
+        store.edit { prefs ->
+            val current = parseReminderOverrides(prefs[CALENDAR_REMINDER_OVERRIDE_KEY]).toMutableMap()
+            current.applyOverride(calendarId, override)
+            prefs[CALENDAR_REMINDER_OVERRIDE_KEY] = serializeReminderOverrides(current)
+        }
+    }
+
+    /**
+     * Per-calendar overrides of [defaultAllDayReminderMinutes] for **all-day**
+     * events, with the same semantics as [perCalendarReminderOverride] (absent =
+     * inherit the global all-day default; present null = no reminder).
+     */
+    val perCalendarAllDayReminderOverride: Flow<Map<Long, Int?>> = store.data.map { prefs ->
+        parseReminderOverrides(prefs[CALENDAR_ALLDAY_REMINDER_OVERRIDE_KEY])
+    }
+
+    suspend fun setCalendarAllDayReminderOverride(
+        calendarId: Long,
+        override: CalendarReminderOverride,
+    ) {
+        store.edit { prefs ->
+            val current =
+                parseReminderOverrides(prefs[CALENDAR_ALLDAY_REMINDER_OVERRIDE_KEY]).toMutableMap()
+            current.applyOverride(calendarId, override)
+            prefs[CALENDAR_ALLDAY_REMINDER_OVERRIDE_KEY] = serializeReminderOverrides(current)
+        }
+    }
+
+    private fun parseFormFields(stored: String?): Set<EventFormField> = when (stored) {
+        null -> DEFAULT_FORM_FIELDS
+        else -> stored.split(',')
+            .mapNotNull { name -> EventFormField.entries.firstOrNull { it.name == name.trim() } }
+            .toSet()
+    }
+
+    companion object {
+        internal val THEME_MODE_KEY = stringPreferencesKey("theme_mode")
+        internal val DYNAMIC_COLOR_KEY = booleanPreferencesKey("dynamic_color")
+        internal val WEEK_START_KEY = stringPreferencesKey("week_start")
+        internal val FORM_FIELDS_KEY = stringPreferencesKey("event_form_default_fields")
+        internal val REMINDERS_ENABLED_KEY = booleanPreferencesKey("reminders_enabled")
+        internal val REMINDER_ONBOARDING_KEY = booleanPreferencesKey("reminder_onboarding_done")
+        internal val ALLOW_COLOR_UNSUPPORTED_KEY =
+            booleanPreferencesKey("allow_color_unsupported_calendars")
+        internal val DEFAULT_REMINDER_KEY = stringPreferencesKey("default_reminder_minutes")
+        internal val DEFAULT_ALLDAY_REMINDER_KEY =
+            stringPreferencesKey("default_allday_reminder_minutes")
+        internal val ALLDAY_REMINDER_TIME_KEY =
+            intPreferencesKey("allday_reminder_time_minutes")
+        /** 09:00 as minutes from midnight; the default all-day reminder fire time. */
+        internal const val DEFAULT_ALLDAY_REMINDER_TIME = 540
+        private const val MINUTES_PER_DAY = 1_440
+        internal val CALENDAR_REMINDER_OVERRIDE_KEY =
+            stringPreferencesKey("per_calendar_reminder_override")
+        internal val CALENDAR_ALLDAY_REMINDER_OVERRIDE_KEY =
+            stringPreferencesKey("per_calendar_allday_reminder_override")
+        internal val DEFAULT_FORM_FIELDS =
+            setOf(EventFormField.Location, EventFormField.Description)
+    }
+}
+
+/** A calendar's reminder-default override (see [SettingsPrefs.perCalendarReminderOverride]). */
+sealed interface CalendarReminderOverride {
+    /** No override — the calendar uses the global default. */
+    data object Inherit : CalendarReminderOverride
+    /** Explicit "no reminder" for this calendar, regardless of the global default. */
+    data object None : CalendarReminderOverride
+    /** A specific lead time in minutes before the event start. */
+    data class Minutes(val minutes: Int) : CalendarReminderOverride
+}
+
+/**
+ * The lead time to prefill on a new event: the matching per-calendar override
+ * if [calendarId] has one for this event kind, otherwise the global default for
+ * that kind. All-day events consult [allDayOverrides] / [allDayGlobal]; timed
+ * events consult [timedOverrides] / [timedGlobal]. `null` = no reminder. Pure so
+ * it can be unit-tested.
+ */
+fun resolveDefaultReminder(
+    timedGlobal: Int?,
+    allDayGlobal: Int?,
+    timedOverrides: Map<Long, Int?>,
+    allDayOverrides: Map<Long, Int?>,
+    calendarId: Long?,
+    isAllDay: Boolean,
+): Int? {
+    val overrides = if (isAllDay) allDayOverrides else timedOverrides
+    val global = if (isAllDay) allDayGlobal else timedGlobal
+    return if (calendarId != null && overrides.containsKey(calendarId)) {
+        overrides[calendarId]
+    } else {
+        global
+    }
+}
+
+/** Apply a [CalendarReminderOverride] to an override map ([Inherit] removes the key). */
+private fun MutableMap<Long, Int?>.applyOverride(
+    calendarId: Long,
+    override: CalendarReminderOverride,
+) {
+    when (override) {
+        CalendarReminderOverride.Inherit -> remove(calendarId)
+        CalendarReminderOverride.None -> put(calendarId, null)
+        is CalendarReminderOverride.Minutes -> put(calendarId, override.minutes)
+    }
+}
+
+private const val NONE = "none"
+private const val ENTRY_SEP = ";"
+private const val KEY_VALUE_SEP = "="
+
+private fun String?.toReminderMinutes(): Int? = when (this) {
+    null, "", NONE -> null
+    else -> toIntOrNull()
+}
+
+private fun parseReminderOverrides(stored: String?): Map<Long, Int?> {
+    if (stored.isNullOrBlank()) return emptyMap()
+    return stored.split(ENTRY_SEP).mapNotNull { entry ->
+        val parts = entry.split(KEY_VALUE_SEP).takeIf { it.size == 2 } ?: return@mapNotNull null
+        val id = parts[0].toLongOrNull() ?: return@mapNotNull null
+        val value = if (parts[1] == NONE) null else parts[1].toIntOrNull() ?: return@mapNotNull null
+        id to value
+    }.toMap()
+}
+
+private fun serializeReminderOverrides(map: Map<Long, Int?>): String =
+    map.entries.joinToString(ENTRY_SEP) { (id, minutes) -> "$id$KEY_VALUE_SEP${minutes ?: NONE}" }
+
+private inline fun <reified E : Enum<E>> String?.toEnum(default: E): E =
+    this?.let { stored -> enumValues<E>().firstOrNull { it.name == stored } } ?: default

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/EventReminderReceiver.kt

@@ -0,0 +1,57 @@
+package de.jeanlucmakiola.calendula.data.reminders
+
+import android.Manifest
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.pm.PackageManager
+import android.provider.CalendarContract
+import androidx.core.content.ContextCompat
+import dagger.hilt.android.AndroidEntryPoint
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+
+/**
+ * Becomes the app that turns the calendar provider's reminder alarms into
+ * visible notifications (the Etar model — the provider broadcasts
+ * `EVENT_REMINDER` at reminder time but posts nothing itself).
+ *
+ * The broadcast's data URI only carries the alarm time, so it is ignored:
+ * we query every still-scheduled, due `CalendarAlerts` row ourselves, post
+ * them, and mark them fired. Posting happens before marking — a crash in
+ * between re-posts silently (same tag) rather than losing the reminder.
+ */
+@AndroidEntryPoint
+class EventReminderReceiver : BroadcastReceiver() {
+
+    @Inject lateinit var alertStore: ReminderAlertStore
+    @Inject lateinit var notifier: ReminderNotifier
+    @Inject lateinit var settingsPrefs: SettingsPrefs
+
+    override fun onReceive(context: Context, intent: Intent) {
+        if (intent.action != CalendarContract.ACTION_EVENT_REMINDER) return
+        val readGranted = ContextCompat.checkSelfPermission(
+            context, Manifest.permission.READ_CALENDAR,
+        ) == PackageManager.PERMISSION_GRANTED
+        if (!readGranted || !notifier.canPost()) return
+
+        val pendingResult = goAsync()
+        CoroutineScope(SupervisorJob() + Dispatchers.IO).launch {
+            try {
+                if (settingsPrefs.remindersEnabled.first()) {
+                    val now = System.currentTimeMillis()
+                    val due = alertStore.dueAlerts(now)
+                    due.forEach(notifier::post)
+                    alertStore.markFired(due.map { it.alertId }, now)
+                }
+            } finally {
+                pendingResult.finish()
+            }
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/ReminderAlertStore.kt

@@ -0,0 +1,112 @@
+package de.jeanlucmakiola.calendula.data.reminders
+
+import android.content.ContentValues
+import android.content.Context
+import android.provider.CalendarContract
+import android.util.Log
+import dagger.hilt.android.qualifiers.ApplicationContext
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * One due row of the provider's `CalendarAlerts` table (a join with Events).
+ * Stays in the data layer: alerts feed the notification path only and never
+ * reach a screen, so there is no domain model for them.
+ */
+data class ReminderAlert(
+    val alertId: Long,
+    val eventId: Long,
+    val beginMillis: Long,
+    val endMillis: Long,
+    /** Raw event title; may be blank — the notifier substitutes "(no title)". */
+    val title: String,
+    val location: String?,
+    val isAllDay: Boolean,
+)
+
+/**
+ * Seam over the `CalendarAlerts` table so the receiver logic can be exercised
+ * without a ContentResolver. The provider creates these rows itself — only
+ * for `METHOD_ALERT` reminders (verified in AOSP `CalendarAlarmManager`), so
+ * email reminders never show up here.
+ */
+interface ReminderAlertStore {
+
+    /** Alerts that are due (`ALARM_TIME` has passed) and still unhandled. */
+    fun dueAlerts(nowMillis: Long): List<ReminderAlert>
+
+    /**
+     * Mark the given alerts handled (`STATE_FIRED`) so a later broadcast does
+     * not surface them again. Best effort: this write needs `WRITE_CALENDAR`,
+     * which the user may have declined — then re-broadcasts silently replace
+     * the already-posted notifications instead (same tag, alert-once).
+     */
+    fun markFired(alertIds: List<Long>, nowMillis: Long)
+}
+
+@Singleton
+class AndroidReminderAlertStore @Inject constructor(
+    @ApplicationContext private val context: Context,
+) : ReminderAlertStore {
+
+    override fun dueAlerts(nowMillis: Long): List<ReminderAlert> = context.contentResolver.query(
+        CalendarContract.CalendarAlerts.CONTENT_URI,
+        PROJECTION,
+        CalendarContract.CalendarAlerts.STATE + " = ? AND " +
+            CalendarContract.CalendarAlerts.ALARM_TIME + " <= ?",
+        arrayOf(
+            CalendarContract.CalendarAlerts.STATE_SCHEDULED.toString(),
+            nowMillis.toString(),
+        ),
+        CalendarContract.CalendarAlerts.BEGIN + " ASC",
+    )?.use { c ->
+        buildList {
+            while (c.moveToNext()) {
+                add(
+                    ReminderAlert(
+                        alertId = c.getLong(0),
+                        eventId = c.getLong(1),
+                        beginMillis = c.getLong(2),
+                        endMillis = c.getLong(3),
+                        title = c.getString(4).orEmpty(),
+                        location = c.getString(5)?.takeIf { it.isNotBlank() },
+                        isAllDay = c.getInt(6) == 1,
+                    ),
+                )
+            }
+        }
+    } ?: emptyList()
+
+    override fun markFired(alertIds: List<Long>, nowMillis: Long) {
+        if (alertIds.isEmpty()) return
+        val values = ContentValues().apply {
+            put(CalendarContract.CalendarAlerts.STATE, CalendarContract.CalendarAlerts.STATE_FIRED)
+            put(CalendarContract.CalendarAlerts.RECEIVED_TIME, nowMillis)
+            put(CalendarContract.CalendarAlerts.NOTIFY_TIME, nowMillis)
+        }
+        try {
+            context.contentResolver.update(
+                CalendarContract.CalendarAlerts.CONTENT_URI,
+                values,
+                CalendarContract.CalendarAlerts._ID +
+                    " IN (" + alertIds.joinToString(",") + ")",
+                null,
+            )
+        } catch (e: SecurityException) {
+            Log.w(TAG, "Cannot mark alerts fired without WRITE_CALENDAR", e)
+        }
+    }
+
+    private companion object {
+        const val TAG = "ReminderAlertStore"
+        val PROJECTION = arrayOf(
+            CalendarContract.CalendarAlerts._ID,
+            CalendarContract.CalendarAlerts.EVENT_ID,
+            CalendarContract.CalendarAlerts.BEGIN,
+            CalendarContract.CalendarAlerts.END,
+            CalendarContract.CalendarAlerts.TITLE,
+            CalendarContract.CalendarAlerts.EVENT_LOCATION,
+            CalendarContract.CalendarAlerts.ALL_DAY,
+        )
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/ReminderNotifier.kt

@@ -0,0 +1,101 @@
+package de.jeanlucmakiola.calendula.data.reminders
+
+import android.Manifest
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.PendingIntent
+import android.content.Context
+import android.content.pm.PackageManager
+import android.os.Build
+import android.util.Log
+import androidx.core.app.NotificationCompat
+import androidx.core.app.NotificationManagerCompat
+import androidx.core.content.ContextCompat
+import dagger.hilt.android.qualifiers.ApplicationContext
+import de.jeanlucmakiola.calendula.MainActivity
+import de.jeanlucmakiola.calendula.R
+import java.time.ZoneId
+import java.util.Locale
+import javax.inject.Inject
+import javax.inject.Singleton
+
+/**
+ * Posts one notification per due reminder alert on a dedicated channel.
+ * Tapping opens the event's detail screen; the tag is the alert id, so a
+ * re-broadcast of an alert we couldn't mark fired replaces its notification
+ * silently ([NotificationCompat.Builder.setOnlyAlertOnce]) instead of
+ * duplicating it.
+ */
+@Singleton
+class ReminderNotifier @Inject constructor(
+    @ApplicationContext private val context: Context,
+) {
+
+    /** False when the user declined `POST_NOTIFICATIONS` or muted the app. */
+    fun canPost(): Boolean {
+        val granted = Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU ||
+            ContextCompat.checkSelfPermission(context, Manifest.permission.POST_NOTIFICATIONS) ==
+            PackageManager.PERMISSION_GRANTED
+        return granted && NotificationManagerCompat.from(context).areNotificationsEnabled()
+    }
+
+    fun post(alert: ReminderAlert) {
+        ensureChannel()
+        val title = alert.title.ifBlank { context.getString(R.string.event_untitled) }
+        val time = reminderTimeText(
+            beginMillis = alert.beginMillis,
+            endMillis = alert.endMillis,
+            isAllDay = alert.isAllDay,
+            zone = ZoneId.systemDefault(),
+            locale = Locale.getDefault(),
+        )
+        val text = listOfNotNull(time, alert.location).joinToString(" · ")
+        val notification = NotificationCompat.Builder(context, CHANNEL_ID)
+            .setSmallIcon(R.drawable.ic_notification)
+            .setContentTitle(title)
+            .setContentText(text)
+            .setWhen(alert.beginMillis)
+            .setShowWhen(false)
+            .setCategory(NotificationCompat.CATEGORY_EVENT)
+            .setPriority(NotificationCompat.PRIORITY_HIGH)
+            .setAutoCancel(true)
+            .setOnlyAlertOnce(true)
+            .setContentIntent(detailIntent(alert))
+            .build()
+        try {
+            NotificationManagerCompat.from(context)
+                .notify(alert.alertId.toString(), NOTIFICATION_ID, notification)
+        } catch (e: SecurityException) {
+            // POST_NOTIFICATIONS was revoked between canPost() and here.
+            Log.w(TAG, "Could not post reminder for event ${alert.eventId}", e)
+        }
+    }
+
+    private fun detailIntent(alert: ReminderAlert): PendingIntent = PendingIntent.getActivity(
+        context,
+        /* requestCode = */ alert.alertId.toInt(),
+        MainActivity.eventDetailIntent(context, alert.eventId, alert.beginMillis, alert.endMillis),
+        PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE,
+    )
+
+    /** Channel creation is idempotent; re-running refreshes the localized name. */
+    private fun ensureChannel() {
+        val channel = NotificationChannel(
+            CHANNEL_ID,
+            context.getString(R.string.reminder_channel_name),
+            NotificationManager.IMPORTANCE_HIGH,
+        ).apply {
+            description = context.getString(R.string.reminder_channel_description)
+        }
+        NotificationManagerCompat.from(context).createNotificationChannel(channel)
+    }
+
+    private companion object {
+        const val TAG = "ReminderNotifier"
+        const val CHANNEL_ID = "reminders"
+
+        // One id, distinct tags: the tag (alert id) already keys the
+        // notification, so a fixed id keeps cancellation/replacement simple.
+        const val NOTIFICATION_ID = 1
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/data/reminders/ReminderTimeText.kt

@@ -0,0 +1,56 @@
+package de.jeanlucmakiola.calendula.data.reminders
+
+import java.time.Instant
+import java.time.ZoneId
+import java.time.ZoneOffset
+import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
+import java.util.Locale
+
+/**
+ * The one line of time context in a reminder notification. Pure so it can be
+ * JVM-tested:
+ *
+ * - timed, same day:      "09:30 – 10:00"
+ * - timed, crossing days: "11 Jun, 23:30 – 12 Jun, 00:30" (medium date + short time)
+ * - all-day, one day:     "11 Jun 2026"
+ * - all-day, multi-day:   "11 Jun 2026 – 12 Jun 2026"
+ *
+ * All-day instances store UTC midnights with an exclusive end, so they are
+ * read in UTC and the end day is the last *covered* day.
+ */
+fun reminderTimeText(
+    beginMillis: Long,
+    endMillis: Long,
+    isAllDay: Boolean,
+    zone: ZoneId,
+    locale: Locale,
+): String {
+    if (isAllDay) {
+        val dateFormat = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).withLocale(locale)
+        // (atZone().toLocalDate() instead of LocalDate.ofInstant — API 34+)
+        val firstDay = Instant.ofEpochMilli(beginMillis).atZone(ZoneOffset.UTC).toLocalDate()
+        val lastDay = Instant.ofEpochMilli(endMillis).atZone(ZoneOffset.UTC).toLocalDate()
+            .minusDays(1)
+            .coerceAtLeast(firstDay)
+        return if (lastDay == firstDay) {
+            dateFormat.format(firstDay)
+        } else {
+            dateFormat.format(firstDay) + RANGE + dateFormat.format(lastDay)
+        }
+    }
+
+    val timeFormat = DateTimeFormatter.ofLocalizedTime(FormatStyle.SHORT).withLocale(locale)
+    val begin = Instant.ofEpochMilli(beginMillis).atZone(zone)
+    val end = Instant.ofEpochMilli(endMillis).atZone(zone)
+    return if (begin.toLocalDate() == end.toLocalDate()) {
+        timeFormat.format(begin) + RANGE + timeFormat.format(end)
+    } else {
+        val dateTimeFormat = DateTimeFormatter
+            .ofLocalizedDateTime(FormatStyle.MEDIUM, FormatStyle.SHORT)
+            .withLocale(locale)
+        dateTimeFormat.format(begin) + RANGE + dateTimeFormat.format(end)
+    }
+}
+
+private const val RANGE = " – "

app/src/main/java/de/jeanlucmakiola/calendula/domain/EventForm.kt

@@ -0,0 +1,163 @@
+package de.jeanlucmakiola.calendula.domain
+
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Instant
+
+/**
+ * User input for creating an event (and, from v1.3, editing one). Times are
+ * wall-clock values in the device zone; the data layer translates them to
+ * provider millis (all-day events normalise to UTC midnights there).
+ */
+data class EventForm(
+    val calendarId: Long?,
+    val title: String = "",
+    val isAllDay: Boolean = false,
+    val start: LocalDateTime,
+    val end: LocalDateTime,
+    val location: String = "",
+    val description: String = "",
+    /** Reminder lead times in minutes before the start, deduplicated. */
+    val reminders: List<Int> = emptyList(),
+    val availability: Availability = Availability.Busy,
+    val accessLevel: AccessLevel = AccessLevel.Default,
+    /**
+     * Bare RRULE value (`Events.RRULE` convention, no "RRULE:" prefix); null
+     * means a one-off event. May hold rules the simple picker can't express —
+     * those are kept verbatim until the user picks something else.
+     */
+    val rrule: String? = null,
+    /**
+     * The event's own colour, or null to inherit the calendar's colour.
+     * [colorKey] is a `Colors.COLOR_KEY` from the calendar account's published
+     * event palette (Google, some CalDAV) — written as `EVENT_COLOR_KEY` so it
+     * round-trips through sync. When it is null but [color] is set, [color] is
+     * a raw ARGB written as `EVENT_COLOR` (local calendars, or synced ones the
+     * user opted into despite no palette). [color] mirrors the key's swatch when
+     * [colorKey] is set, so the picker can highlight it.
+     */
+    val colorKey: String? = null,
+    val color: Int? = null,
+)
+
+/**
+ * The form's optional sections. Which ones show by default is a user setting;
+ * the rest unfold behind a "more fields" button.
+ */
+enum class EventFormField {
+    Location,
+    Description,
+    Reminders,
+    Recurrence,
+    Availability,
+    Visibility,
+    Color,
+}
+
+enum class EventFormProblem {
+    /** No target calendar — none picked and no writable calendar exists. */
+    NoCalendar,
+    EndBeforeStart,
+    /** The recurrence's UNTIL date lies before the event's first day. */
+    RecurrenceEndsBeforeStart,
+}
+
+/**
+ * Validation; an empty set means the form can be saved. A blank title is
+ * allowed (display falls back to "(No title)", matching the provider), and a
+ * zero-length timed event is allowed (spec §8: instant events exist).
+ */
+/**
+ * Prefill the edit form from a loaded event. [beginMillis]/[endMillis] are the
+ * tapped occurrence's own times (`Instances.BEGIN`/`END`), not the series
+ * start — the data layer later turns a time edit into a delta on the series.
+ *
+ * All-day provider times are UTC midnights with an exclusive end; the form
+ * shows the last covered day and keeps placeholder wall-clock times in case
+ * the user switches the event to timed.
+ */
+fun EventDetail.toEditForm(beginMillis: Long, endMillis: Long, zone: TimeZone): EventForm {
+    val (start, end) = if (instance.isAllDay) {
+        val startDate = Instant.fromEpochMilliseconds(beginMillis)
+            .toLocalDateTime(TimeZone.UTC).date
+        val endExclusive = Instant.fromEpochMilliseconds(endMillis)
+            .toLocalDateTime(TimeZone.UTC).date
+        val endDate = maxOf(startDate, LocalDate.fromEpochDays(endExclusive.toEpochDays() - 1))
+        LocalDateTime(startDate, LocalTime(9, 0)) to LocalDateTime(endDate, LocalTime(10, 0))
+    } else {
+        Instant.fromEpochMilliseconds(beginMillis).toLocalDateTime(zone) to
+            Instant.fromEpochMilliseconds(endMillis).toLocalDateTime(zone)
+    }
+    return EventForm(
+        calendarId = instance.calendarId,
+        title = instance.title,
+        isAllDay = instance.isAllDay,
+        start = start,
+        end = end,
+        location = instance.location.orEmpty(),
+        description = description.orEmpty(),
+        reminders = reminders.map { it.minutes }.distinct().sorted(),
+        availability = availability,
+        accessLevel = accessLevel,
+        rrule = rrule?.removePrefix("RRULE:")?.takeIf { it.isNotBlank() },
+        // The provider fills EVENT_COLOR from the key, so [color] is the
+        // swatch either way; a null colour means the event inherits its
+        // calendar's colour.
+        colorKey = eventColorKey,
+        color = eventColor,
+    )
+}
+
+/**
+ * What the edit form saw when it loaded — compared against a fresh read at
+ * save time to detect external changes (sync, another device) that landed
+ * while the form was open. The raw row times ride along because
+ * [toEditForm] derives the form's times from the *tapped occurrence*, so
+ * re-deriving with the same occurrence would mask an externally moved
+ * event. Not covered (the form can't write them, and the dirty-checked
+ * write can't clobber them): attendees, status, the user's own response,
+ * reminder methods, and a recurring event's duration.
+ */
+data class EditSnapshot(
+    val form: EventForm,
+    /** The raw Events-row times (for recurring events: the series anchor). */
+    val rowStart: Instant,
+    val rowEnd: Instant,
+)
+
+fun EventDetail.toEditSnapshot(beginMillis: Long, endMillis: Long, zone: TimeZone): EditSnapshot =
+    EditSnapshot(
+        form = toEditForm(beginMillis, endMillis, zone),
+        rowStart = instance.start,
+        rowEnd = instance.end,
+    )
+
+/**
+ * The optional sections that hold a value in [form] — when editing, these
+ * must be visible regardless of the user's default-fields setting, or the
+ * data they carry would be invisible (though still preserved).
+ */
+fun EventForm.populatedFields(): Set<EventFormField> = buildSet {
+    if (location.isNotBlank()) add(EventFormField.Location)
+    if (description.isNotBlank()) add(EventFormField.Description)
+    if (reminders.isNotEmpty()) add(EventFormField.Reminders)
+    if (rrule != null) add(EventFormField.Recurrence)
+    if (availability != Availability.Busy) add(EventFormField.Availability)
+    if (accessLevel != AccessLevel.Default) add(EventFormField.Visibility)
+    if (colorKey != null || color != null) add(EventFormField.Color)
+}
+
+fun EventForm.problems(): Set<EventFormProblem> = buildSet {
+    if (calendarId == null) add(EventFormProblem.NoCalendar)
+    val endsTooEarly = if (isAllDay) end.date < start.date else end < start
+    if (endsTooEarly) add(EventFormProblem.EndBeforeStart)
+    // An UNTIL before the first day would make the provider generate zero
+    // occurrences — the event would silently vanish from every view.
+    val recurrenceEnd = rrule?.let(::parseSimpleRecurrence)?.end
+    if (recurrenceEnd is RecurrenceEnd.Until && recurrenceEnd.date < start.date) {
+        add(EventFormProblem.RecurrenceEndsBeforeStart)
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/domain/Models.kt

@@ -9,6 +9,23 @@ data class CalendarSource(
     val accountType: String,
     val color: Int,
     val isVisibleInSystem: Boolean,
+    /**
+     * Whether events in this calendar can be created/edited/deleted
+     * (`Calendars.CALENDAR_ACCESS_LEVEL` >= contributor). False for WebCal
+     * subscriptions, birthday calendars and other read-only sources.
+     */
+    val canModifyContents: Boolean = false,
+    /**
+     * A device-only calendar the app itself owns (`ACCOUNT_TYPE_LOCAL`): it has
+     * no sync backend, so the app can rename / recolor / delete it. Synced
+     * calendars (Google, DAVx5, …) are managed in their own source app instead.
+     */
+    val isLocal: Boolean = false,
+    /**
+     * Free-text note for a local calendar (stored in `CAL_SYNC1`, which the app
+     * owns for its own calendars). Always null for synced calendars.
+     */
+    val description: String? = null,
 )
 
 data class EventInstance(
@@ -29,12 +46,51 @@ data class EventDetail(
     val organizer: String?,
     val attendees: List<Attendee>,
     val rrule: String?,
+    /** Reminders (VALARM) configured on the event, ascending lead time. */
+    val reminders: List<Reminder> = emptyList(),
+    /** Confirmed / Tentative / Cancelled (`Events.STATUS`). */
+    val status: EventStatus = EventStatus.Confirmed,
+    /** Busy / Free (`Events.AVAILABILITY`, the iCal TRANSP field). */
+    val availability: Availability = Availability.Busy,
+    /** Default / Private / Confidential / Public (`Events.ACCESS_LEVEL`). */
+    val accessLevel: AccessLevel = AccessLevel.Default,
+    /** Raw zone id (`Events.EVENT_TIMEZONE`), e.g. "Europe/Berlin"; null if unset. */
+    val eventTimezone: String? = null,
+    /** This device user's own response (`Events.SELF_ATTENDEE_STATUS`). */
+    val selfStatus: AttendeeStatus = AttendeeStatus.Unknown,
+    /**
+     * The event's own raw colour (`Events.EVENT_COLOR`), null when the event
+     * inherits its calendar's colour. Unlike [EventInstance.color] (which
+     * already folds in the calendar fallback for display) this stays null so
+     * the edit form can tell "has own colour" from "inherits".
+     */
+    val eventColor: Int? = null,
+    /** The event's `Events.EVENT_COLOR_KEY` (a calendar-palette key), or null. */
+    val eventColorKey: String? = null,
 )
 
+/**
+ * One selectable event colour published by a calendar's account
+ * (`CalendarContract.Colors`, `TYPE_EVENT`): [key] is the account-scoped
+ * `COLOR_KEY` written as `EVENT_COLOR_KEY` (so the colour survives sync),
+ * [argb] is the swatch it renders as.
+ */
+data class EventColorOption(val key: String, val argb: Int)
+
 data class Attendee(
     val name: String,
     val email: String?,
     val status: AttendeeStatus,
+    /** Organizer / performer / speaker / plain attendee (`ATTENDEE_RELATIONSHIP`). */
+    val relationship: AttendeeRelationship = AttendeeRelationship.None,
+    /** Required / optional / resource (`ATTENDEE_TYPE`). */
+    val type: AttendeeType = AttendeeType.None,
+)
+
+data class Reminder(
+    /** Lead time before the event start, in minutes. `-1` means the provider default. */
+    val minutes: Int,
+    val method: ReminderMethod,
 )
 
 enum class AttendeeStatus {
@@ -45,6 +101,58 @@ enum class AttendeeStatus {
     Unknown,
 }
 
+enum class AttendeeRelationship {
+    Organizer,
+    Attendee,
+    Performer,
+    Speaker,
+    None,
+}
+
+enum class AttendeeType {
+    Required,
+    Optional,
+    Resource,
+    None,
+}
+
+enum class ReminderMethod {
+    Alert,
+    Email,
+    Sms,
+    Alarm,
+    Default,
+}
+
+enum class EventStatus {
+    Confirmed,
+    Tentative,
+    Cancelled,
+}
+
+enum class Availability {
+    Busy,
+    Free,
+    Tentative,
+}
+
+enum class AccessLevel {
+    Default,
+    Public,
+    Private,
+    Confidential,
+}
+
+/**
+ * How far a write to a recurring event reaches. Non-recurring events always
+ * use [AllEvents] (there is only one).
+ */
+enum class RecurringWriteScope {
+    ThisEvent,
+    ThisAndFollowing,
+    AllEvents,
+}
+
 enum class FailureReason {
     PermissionRevoked,
     NoCalendarsConfigured,

app/src/main/java/de/jeanlucmakiola/calendula/domain/Recurrence.kt

@@ -0,0 +1,197 @@
+package de.jeanlucmakiola.calendula.domain
+
+import kotlinx.datetime.DayOfWeek
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.isoDayNumber
+import kotlinx.datetime.number
+import kotlinx.datetime.toInstant
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Instant
+
+/**
+ * The recurrence shapes the simple picker can express (v1.3): a frequency,
+ * an interval, weekly weekday picks, and an optional end. Anything beyond
+ * that (ordinal BYDAY like "2TH", BYMONTHDAY, EXDATE rules, …) stays a raw
+ * RRULE string the picker shows as "custom" and leaves untouched unless the
+ * user replaces it.
+ */
+data class SimpleRecurrence(
+    val freq: RecurrenceFreq,
+    val interval: Int = 1,
+    val end: RecurrenceEnd = RecurrenceEnd.Never,
+    /**
+     * Weekly only: the weekdays the rule fires on (RRULE BYDAY). Empty means
+     * no BYDAY part — the provider derives the day from DTSTART.
+     */
+    val byDays: Set<DayOfWeek> = emptySet(),
+)
+
+enum class RecurrenceFreq {
+    Daily,
+    Weekly,
+    Monthly,
+    Yearly,
+}
+
+sealed interface RecurrenceEnd {
+    data object Never : RecurrenceEnd
+
+    /** Last day on which an occurrence may fall (inclusive). */
+    data class Until(val date: LocalDate) : RecurrenceEnd
+
+    /** Total number of occurrences, counting the first. */
+    data class Count(val times: Int) : RecurrenceEnd
+}
+
+/**
+ * Parse an RRULE into the picker's simple shape, or null when the rule uses
+ * parts the picker can't represent (so the UI preserves the original string).
+ * Accepts an optional leading "RRULE:" and an ignored WKST part. A datetime
+ * UNTIL is converted from UTC into [zone] before its date is taken, mirroring
+ * [toRRule].
+ */
+fun parseSimpleRecurrence(
+    rrule: String,
+    zone: TimeZone = TimeZone.currentSystemDefault(),
+): SimpleRecurrence? {
+    val parts = rrule.removePrefix("RRULE:").split(';')
+        .filter { it.isNotBlank() }
+        .associate { token ->
+            val eq = token.indexOf('=')
+            if (eq <= 0) return null
+            token.substring(0, eq).uppercase() to token.substring(eq + 1)
+        }
+    if (parts.keys.any { it !in setOf("FREQ", "INTERVAL", "UNTIL", "COUNT", "WKST", "BYDAY") }) {
+        return null
+    }
+
+    val freq = when (parts["FREQ"]?.uppercase()) {
+        "DAILY" -> RecurrenceFreq.Daily
+        "WEEKLY" -> RecurrenceFreq.Weekly
+        "MONTHLY" -> RecurrenceFreq.Monthly
+        "YEARLY" -> RecurrenceFreq.Yearly
+        else -> return null
+    }
+    val interval = parts["INTERVAL"]?.let { it.toIntOrNull()?.takeIf { n -> n >= 1 } ?: return null } ?: 1
+
+    // BYDAY is simple only as plain weekday picks on a weekly rule; ordinal
+    // forms ("2TH" = second Thursday) and BYDAY on other frequencies are not.
+    val byDays = parts["BYDAY"]?.let { raw ->
+        if (freq != RecurrenceFreq.Weekly) return null
+        raw.split(',').map { token -> rruleDay(token.trim()) ?: return null }.toSet()
+    } ?: emptySet()
+
+    val until = parts["UNTIL"]
+    val count = parts["COUNT"]
+    if (until != null && count != null) return null
+    val end = when {
+        until != null -> RecurrenceEnd.Until(parseUntilDate(until, zone) ?: return null)
+        count != null -> RecurrenceEnd.Count(count.toIntOrNull()?.takeIf { it >= 1 } ?: return null)
+        else -> RecurrenceEnd.Never
+    }
+    return SimpleRecurrence(freq, interval, end, byDays)
+}
+
+/**
+ * Render as a provider-ready RRULE value (no "RRULE:" prefix —
+ * `CalendarContract.Events.RRULE` stores the bare value). UNTIL is written as
+ * the end of the chosen day *in [zone]*, expressed in UTC: the recurrence
+ * engine has been observed applying UNTIL coarsely after converting it into
+ * the event's timezone, so a plain `T235959Z` can leak one extra day for
+ * zones ahead of UTC.
+ */
+fun SimpleRecurrence.toRRule(zone: TimeZone = TimeZone.currentSystemDefault()): String = buildString {
+    append("FREQ=")
+    append(
+        when (freq) {
+            RecurrenceFreq.Daily -> "DAILY"
+            RecurrenceFreq.Weekly -> "WEEKLY"
+            RecurrenceFreq.Monthly -> "MONTHLY"
+            RecurrenceFreq.Yearly -> "YEARLY"
+        },
+    )
+    if (interval > 1) append(";INTERVAL=$interval")
+    if (freq == RecurrenceFreq.Weekly && byDays.isNotEmpty()) {
+        append(";BYDAY=")
+        append(
+            byDays.sortedBy { it.isoDayNumber }
+                .joinToString(",") { RRULE_DAY_CODES.getValue(it) },
+        )
+    }
+    when (val e = end) {
+        RecurrenceEnd.Never -> Unit
+        is RecurrenceEnd.Until -> {
+            val utc = LocalDateTime(e.date, LocalTime(23, 59, 59))
+                .toInstant(zone)
+                .toLocalDateTime(TimeZone.UTC)
+            append(
+                ";UNTIL=%04d%02d%02dT%02d%02d%02dZ".format(
+                    utc.year, utc.month.number, utc.day,
+                    utc.hour, utc.minute, utc.second,
+                ),
+            )
+        }
+        is RecurrenceEnd.Count -> append(";COUNT=${e.times}")
+    }
+}
+
+private val RRULE_DAY_CODES: Map<DayOfWeek, String> = mapOf(
+    DayOfWeek.MONDAY to "MO",
+    DayOfWeek.TUESDAY to "TU",
+    DayOfWeek.WEDNESDAY to "WE",
+    DayOfWeek.THURSDAY to "TH",
+    DayOfWeek.FRIDAY to "FR",
+    DayOfWeek.SATURDAY to "SA",
+    DayOfWeek.SUNDAY to "SU",
+)
+
+/** Exact two-letter BYDAY token → weekday; ordinal forms ("2TH") return null. */
+private fun rruleDay(token: String): DayOfWeek? =
+    RRULE_DAY_CODES.entries.firstOrNull { it.value == token.uppercase() }?.key
+
+/**
+ * End an arbitrary RRULE (simple or not) at [untilUtcMillis]: any existing
+ * UNTIL/COUNT is dropped, every other part (BYDAY, INTERVAL, …) survives.
+ * Used for "delete this and all following occurrences" — the caller passes a
+ * moment just before the first occurrence to remove.
+ */
+fun rruleTruncatedAt(rrule: String, untilUtcMillis: Long): String {
+    val kept = rrule.removePrefix("RRULE:").split(';')
+        .filter { it.isNotBlank() }
+        .filterNot { part ->
+            val key = part.substringBefore('=').trim().uppercase()
+            key == "UNTIL" || key == "COUNT"
+        }
+    val until = Instant.fromEpochMilliseconds(untilUtcMillis).toLocalDateTime(TimeZone.UTC)
+    val untilPart = "UNTIL=%04d%02d%02dT%02d%02d%02dZ".format(
+        until.year, until.month.number, until.day,
+        until.hour, until.minute, until.second,
+    )
+    return (kept + untilPart).joinToString(";")
+}
+
+/**
+ * Date of an RRULE UNTIL value ("20260801" or "20260801T215959Z"). Datetime
+ * forms are UTC (RFC 5545); the date is taken after converting into [zone] so
+ * a [toRRule]-rendered value round-trips to the day the user picked.
+ */
+private fun parseUntilDate(raw: String, zone: TimeZone): LocalDate? = runCatching {
+    val date = LocalDate(
+        raw.substring(0, 4).toInt(),
+        raw.substring(4, 6).toInt(),
+        raw.substring(6, 8).toInt(),
+    )
+    if (raw.length >= 15 && raw[8] == 'T') {
+        val time = LocalTime(
+            raw.substring(9, 11).toInt(),
+            raw.substring(11, 13).toInt(),
+            raw.substring(13, 15).toInt(),
+        )
+        LocalDateTime(date, time).toInstant(TimeZone.UTC).toLocalDateTime(zone).date
+    } else {
+        date
+    }
+}.getOrNull()

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/EventDetailIcs.kt

@@ -0,0 +1,29 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import de.jeanlucmakiola.calendula.domain.EventDetail
+
+/**
+ * Build the [IcsEvent] for sharing a single event. We export the event the user
+ * is looking at as a **one-off** VEVENT (no RRULE): the detail screen shows one
+ * occurrence, so "share this event" should hand off exactly that instance, not
+ * a whole series anchored to a possibly-different DTSTART. Reminders are the
+ * already-decoded semantic lead times the detail screen holds.
+ */
+fun EventDetail.toShareIcsEvent(): IcsEvent {
+    val startMillis = instance.start.toEpochMilliseconds()
+    return IcsEvent(
+        uid = deriveIcsUid(existingUid = null, eventId = instance.eventId, dtStartMillis = startMillis),
+        summary = instance.title,
+        start = instance.start,
+        end = instance.end,
+        isAllDay = instance.isAllDay,
+        zoneId = eventTimezone?.takeIf { it.isNotBlank() } ?: "UTC",
+        recurrenceRule = null,
+        location = instance.location,
+        description = description,
+        reminderMinutes = reminders.map { it.minutes },
+        status = status,
+        availability = availability,
+        calendarName = null,
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/IcsDuration.kt

@@ -0,0 +1,40 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+// Android's calendar provider (and Calendula's own writes) use the non-standard
+// single-unit forms P<n>S / P<n>D / P<n>W — seconds without the RFC-required
+// leading T. Matched first; anything else falls through to the general grammar.
+private val DURATION_SINGLE_UNIT = Regex("""([+-]?)P(\d+)([WDS])""")
+private val DURATION_GENERAL =
+    Regex("""([+-]?)P(?:(\d+)W)?(?:(\d+)D)?(?:T(?:(\d+)H)?(?:(\d+)M)?(?:(\d+)S)?)?""")
+
+/**
+ * Milliseconds of a DURATION (`P1D`, `P3600S`, `PT1H30M`, `-PT15M`, `P1W`, …),
+ * sign-aware. Calendula writes `P<days>D` / `P<seconds>S`, but the parser also
+ * accepts the general RFC 5545 grammar so backup `DURATION` rows and foreign
+ * `VALARM` triggers round-trip. Unparseable input is treated as zero.
+ */
+fun parseRfc2445DurationMillis(duration: String?): Long {
+    if (duration.isNullOrBlank()) return 0L
+    val s = duration.trim()
+
+    DURATION_SINGLE_UNIT.matchEntire(s)?.let { m ->
+        val unitSeconds = when (m.groupValues[3]) {
+            "W" -> 7L * 24 * 60 * 60
+            "D" -> 24L * 60 * 60
+            else -> 1L // S
+        }
+        return m.signum() * m.groupValues[2].toLong() * unitSeconds * 1_000L
+    }
+
+    val m = DURATION_GENERAL.matchEntire(s) ?: return 0L
+    val weeks = m.groupValues[2].toLongOrNull() ?: 0L
+    val days = m.groupValues[3].toLongOrNull() ?: 0L
+    val hours = m.groupValues[4].toLongOrNull() ?: 0L
+    val minutes = m.groupValues[5].toLongOrNull() ?: 0L
+    val seconds = m.groupValues[6].toLongOrNull() ?: 0L
+    val totalSeconds = ((((weeks * 7 + days) * 24 + hours) * 60 + minutes) * 60 + seconds)
+    return m.signum() * totalSeconds * 1_000L
+}
+
+/** Sign carried by group 1 (`-` → -1, otherwise +1) of a duration match. */
+private fun MatchResult.signum(): Long = if (groupValues[1] == "-") -1L else 1L

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/IcsEvent.kt

@@ -0,0 +1,43 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import de.jeanlucmakiola.calendula.domain.Availability
+import de.jeanlucmakiola.calendula.domain.EventStatus
+import kotlin.time.Instant
+
+/**
+ * A single event ready to be serialised to a `VEVENT`, decoupled from the
+ * provider so [IcsWriter] stays pure-Kotlin and JVM-testable. [start]/[end] are
+ * absolute instants; [isAllDay] and [recurrenceRule] decide how they are
+ * rendered (see [IcsWriter]'s timezone rule).
+ */
+data class IcsEvent(
+    /** RFC 5545 UID — globally stable across exports (see [deriveIcsUid]). */
+    val uid: String,
+    val summary: String,
+    val start: Instant,
+    /** Exclusive end (for all-day: the next-day midnight, as the provider stores it). */
+    val end: Instant,
+    val isAllDay: Boolean,
+    /** IANA zone id (`Events.EVENT_TIMEZONE`); only used for recurring timed events. */
+    val zoneId: String,
+    /** Bare RRULE value (no `RRULE:` prefix), or null for a one-off event. */
+    val recurrenceRule: String? = null,
+    val location: String? = null,
+    val description: String? = null,
+    /** Reminder lead times in minutes before start (raw provider offsets). */
+    val reminderMinutes: List<Int> = emptyList(),
+    val status: EventStatus = EventStatus.Confirmed,
+    val availability: Availability = Availability.Busy,
+    /** Source calendar name, emitted as `X-CALENDULA-CALENDAR` so a combined backup can fan back out. */
+    val calendarName: String? = null,
+)
+
+/**
+ * The UID to export for a provider event. A row that already carries a UID
+ * (`Events.UID_2445`) keeps it; otherwise we synthesise a **stable** one from
+ * the event id and its DTSTART so the same legacy event yields the same UID
+ * across repeated backups — which keeps a later restore from duplicating it.
+ */
+fun deriveIcsUid(existingUid: String?, eventId: Long, dtStartMillis: Long): String =
+    existingUid?.trim()?.takeIf { it.isNotEmpty() }
+        ?: "$eventId-$dtStartMillis@calendula"

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/IcsParser.kt

@@ -0,0 +1,259 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import de.jeanlucmakiola.calendula.domain.Availability
+import de.jeanlucmakiola.calendula.domain.EventStatus
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.atStartOfDayIn
+import kotlinx.datetime.toInstant
+import kotlin.time.Instant
+
+/**
+ * A `VEVENT` parsed from an `.ics` file — the read-side mirror of [IcsEvent],
+ * but [uid] is nullable (an incoming event may carry none; the insert layer
+ * then assigns one). Times are absolute instants; [isAllDay]/[zoneId] mirror
+ * how the writer encoded them.
+ */
+data class ParsedIcsEvent(
+    val uid: String?,
+    val summary: String,
+    val start: Instant,
+    val end: Instant,
+    val isAllDay: Boolean,
+    val zoneId: String,
+    val recurrenceRule: String? = null,
+    val location: String? = null,
+    val description: String? = null,
+    val reminderMinutes: List<Int> = emptyList(),
+    val status: EventStatus = EventStatus.Confirmed,
+    val availability: Availability = Availability.Busy,
+    val calendarName: String? = null,
+)
+
+/** Things the parser dropped rather than failing — surfaced in the import report. */
+enum class IcsParseWarning {
+    /** A `RECURRENCE-ID` override occurrence (not modelled; only masters import). */
+    ModifiedOccurrenceSkipped,
+
+    /** A `VEVENT` with no parseable `DTSTART`. */
+    EventWithoutStartSkipped,
+
+    /** `ATTENDEE` rows were present; Calendula doesn't import attendees. */
+    AttendeesIgnored,
+
+    /** A `TZID` couldn't be resolved against the device tz database (used local zone). */
+    UnknownTimezone,
+}
+
+data class IcsParseResult(
+    val events: List<ParsedIcsEvent>,
+    val warnings: Set<IcsParseWarning>,
+)
+
+/** Outcome of a bulk `.ics` import into one calendar. */
+data class IcsImportSummary(val imported: Int, val skippedDuplicate: Int)
+
+/**
+ * Hand-rolled RFC 5545 reader, the inverse of [IcsWriter]. Pure and
+ * JVM-testable. Liberal-in/strict-out: unknown properties are ignored, a single
+ * malformed `VEVENT` is skipped (not fatal), and unsupported constructs
+ * (`RECURRENCE-ID`, attendees, unresolved `TZID`) are reported as [warnings]
+ * rather than silently dropped. `VTIMEZONE` blocks are skipped — a `TZID` is
+ * resolved against the OS tz database instead ([deviceZone] is the fallback).
+ */
+class IcsParser(private val deviceZone: TimeZone = TimeZone.currentSystemDefault()) {
+
+    fun parse(text: String): IcsParseResult {
+        val lines = unfoldLines(text)
+        val events = mutableListOf<ParsedIcsEvent>()
+        val warnings = mutableSetOf<IcsParseWarning>()
+        var calendarName: String? = null
+
+        var i = 0
+        while (i < lines.size) {
+            val line = parseContentLine(lines[i])
+            if (line == null) { i++; continue }
+            when {
+                line.isBegin("VEVENT") -> {
+                    val end = indexOfEnd(lines, i + 1, "VEVENT")
+                    parseVevent(lines.subList(i + 1, end), calendarName, warnings)
+                        ?.let(events::add)
+                    i = end + 1
+                }
+                line.isBegin("VTIMEZONE") -> {
+                    // Skipped wholesale; TZIDs resolve against the OS tz database.
+                    i = indexOfEnd(lines, i + 1, "VTIMEZONE") + 1
+                }
+                line.name == "X-WR-CALNAME" -> {
+                    calendarName = unescapeText(line.value).trim().ifEmpty { null }
+                    i++
+                }
+                else -> i++
+            }
+        }
+        return IcsParseResult(events, warnings)
+    }
+
+    private fun parseVevent(
+        body: List<String>,
+        fileCalendarName: String?,
+        warnings: MutableSet<IcsParseWarning>,
+    ): ParsedIcsEvent? {
+        var uid: String? = null
+        var summary = ""
+        var dtStart: IcsDateTime? = null
+        var dtEnd: IcsDateTime? = null
+        var duration: String? = null
+        var rrule: String? = null
+        var location: String? = null
+        var description: String? = null
+        var status = EventStatus.Confirmed
+        var availability = Availability.Busy
+        var calendarName = fileCalendarName
+        val reminders = mutableListOf<Int>()
+        var skipAsOverride = false
+
+        var i = 0
+        while (i < body.size) {
+            val line = parseContentLine(body[i])
+            if (line == null) { i++; continue }
+            when (line.name) {
+                "BEGIN" -> if (line.value.trim().equals("VALARM", true)) {
+                    val end = indexOfEnd(body, i + 1, "VALARM")
+                    parseAlarmMinutes(body.subList(i + 1, end))?.let(reminders::add)
+                    i = end + 1
+                    continue
+                }
+                "UID" -> uid = line.value.trim().ifEmpty { null }
+                "SUMMARY" -> summary = unescapeText(line.value)
+                "DTSTART" -> dtStart = parseIcsDateTime(line, warnings)
+                "DTEND" -> dtEnd = parseIcsDateTime(line, warnings)
+                "DURATION" -> duration = line.value.trim()
+                "RRULE" -> rrule = line.value.trim().ifEmpty { null }
+                "LOCATION" -> location = unescapeText(line.value).ifEmpty { null }
+                "DESCRIPTION" -> description = unescapeText(line.value).ifEmpty { null }
+                "STATUS" -> status = mapIcsStatus(line.value)
+                "TRANSP" -> availability =
+                    if (line.value.trim().equals("TRANSPARENT", true)) Availability.Free
+                    else Availability.Busy
+                "RECURRENCE-ID" -> skipAsOverride = true
+                "ATTENDEE" -> warnings.add(IcsParseWarning.AttendeesIgnored)
+                "X-CALENDULA-CALENDAR" ->
+                    calendarName = unescapeText(line.value).trim().ifEmpty { calendarName }
+            }
+            i++
+        }
+
+        if (skipAsOverride) {
+            warnings.add(IcsParseWarning.ModifiedOccurrenceSkipped)
+            return null
+        }
+        val start = dtStart ?: run {
+            warnings.add(IcsParseWarning.EventWithoutStartSkipped)
+            return null
+        }
+        val end = dtEnd
+            ?: duration?.let {
+                start.copy(
+                    instant = Instant.fromEpochMilliseconds(
+                        start.instant.toEpochMilliseconds() + parseRfc2445DurationMillis(it),
+                    ),
+                )
+            }
+            ?: start
+        return ParsedIcsEvent(
+            uid = uid,
+            summary = summary,
+            start = start.instant,
+            end = end.instant,
+            isAllDay = start.isAllDay,
+            zoneId = start.zoneId,
+            recurrenceRule = rrule,
+            location = location,
+            description = description,
+            reminderMinutes = reminders.distinct(),
+            status = status,
+            availability = availability,
+            calendarName = calendarName,
+        )
+    }
+
+    /** A VALARM's lead time in minutes before start, or null if not a usable relative trigger. */
+    private fun parseAlarmMinutes(body: List<String>): Int? {
+        val trigger = body.asSequence()
+            .mapNotNull { parseContentLine(it) }
+            .firstOrNull { it.name == "TRIGGER" }
+            ?: return null
+        // Absolute (DATE-TIME) triggers can't be expressed as a lead time.
+        if (trigger.params["VALUE"].equals("DATE-TIME", true)) return null
+        val millis = parseRfc2445DurationMillis(trigger.value)
+        // Negative = before start (the normal case) → positive lead minutes.
+        return (-millis / 60_000L).toInt().coerceAtLeast(0)
+    }
+
+    private fun parseIcsDateTime(line: IcsContentLine, warnings: MutableSet<IcsParseWarning>): IcsDateTime? {
+        val raw = line.value.trim()
+        val isDate = line.params["VALUE"].equals("DATE", true) ||
+            (raw.length == 8 && !raw.contains('T'))
+        if (isDate) {
+            val date = parseBasicDate(raw) ?: return null
+            return IcsDateTime(date.atStartOfDayIn(TimeZone.UTC), isAllDay = true, zoneId = "UTC")
+        }
+        val isUtc = raw.endsWith("Z")
+        val ldt = parseBasicDateTime(raw.removeSuffix("Z")) ?: return null
+        if (isUtc) return IcsDateTime(ldt.toInstant(TimeZone.UTC), isAllDay = false, zoneId = "UTC")
+
+        val tzid = line.params["TZID"]
+        val resolved = tzid?.let { id -> runCatching { TimeZone.of(id) }.getOrNull()?.let { id to it } }
+        if (tzid != null && resolved == null) warnings.add(IcsParseWarning.UnknownTimezone)
+        val (zoneId, zone) = resolved ?: (deviceZone.id to deviceZone)
+        return IcsDateTime(ldt.toInstant(zone), isAllDay = false, zoneId = zoneId)
+    }
+
+    private data class IcsDateTime(val instant: Instant, val isAllDay: Boolean, val zoneId: String)
+
+    private companion object {
+        fun IcsContentLine.isBegin(component: String) =
+            name == "BEGIN" && value.trim().equals(component, true)
+
+        /** Index of the matching `END:<component>` at/after [from], or list end. */
+        fun indexOfEnd(lines: List<String>, from: Int, component: String): Int {
+            var i = from
+            while (i < lines.size) {
+                val line = parseContentLine(lines[i])
+                if (line != null && line.name == "END" &&
+                    line.value.trim().equals(component, true)
+                ) {
+                    return i
+                }
+                i++
+            }
+            return lines.size
+        }
+
+        fun mapIcsStatus(value: String): EventStatus = when (value.trim().uppercase()) {
+            "TENTATIVE" -> EventStatus.Tentative
+            "CANCELLED" -> EventStatus.Cancelled
+            else -> EventStatus.Confirmed
+        }
+
+        fun parseBasicDate(s: String): LocalDate? = runCatching {
+            LocalDate(s.substring(0, 4).toInt(), s.substring(4, 6).toInt(), s.substring(6, 8).toInt())
+        }.getOrNull()
+
+        fun parseBasicDateTime(s: String): LocalDateTime? = runCatching {
+            val date = LocalDate(
+                s.substring(0, 4).toInt(), s.substring(4, 6).toInt(), s.substring(6, 8).toInt(),
+            )
+            // Format is YYYYMMDD 'T' HHMMSS; seconds optional.
+            val time = LocalTime(
+                s.substring(9, 11).toInt(),
+                s.substring(11, 13).toInt(),
+                if (s.length >= 15) s.substring(13, 15).toInt() else 0,
+            )
+            LocalDateTime(date, time)
+        }.getOrNull()
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/IcsText.kt

@@ -0,0 +1,155 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+/**
+ * Low-level RFC 5545 text mechanics, kept separate from [IcsWriter] so the
+ * escaping and folding rules can be tested in isolation. Pure Kotlin — no
+ * Android, no time handling.
+ */
+
+/** iCalendar mandates CRLF line breaks, not the platform separator. */
+const val ICS_CRLF: String = "\r\n"
+
+/** RFC 5545 §3.1: content lines SHOULD be folded at 75 octets (excluding the break). */
+private const val MAX_OCTETS = 75
+
+/**
+ * Escape a TEXT value (SUMMARY, DESCRIPTION, LOCATION, …) per RFC 5545 §3.3.11:
+ * backslash, semicolon and comma are escaped, newlines become the literal `\n`.
+ * Backslash is handled first so it doesn't double-escape the others' markers.
+ */
+fun escapeText(value: String): String = buildString(value.length) {
+    for (ch in value) {
+        when (ch) {
+            '\\' -> append("\\\\")
+            ';' -> append("\\;")
+            ',' -> append("\\,")
+            '\n' -> append("\\n")
+            '\r' -> Unit // CR is dropped; a lone CRLF in source text folds to one \n
+            else -> append(ch)
+        }
+    }
+}
+
+/**
+ * Fold a single content line to ≤75 octets per physical line, inserting
+ * `CRLF + space` between segments (the space is part of the 75-octet budget of
+ * the continuation line, so its content caps at 74). Folding counts UTF-8
+ * octets, never splitting a multi-byte character across a boundary.
+ */
+fun foldLine(line: String): String {
+    if (line.toByteArray(Charsets.UTF_8).size <= MAX_OCTETS) return line
+    val out = StringBuilder()
+    var octetsThisLine = 0
+    var first = true
+    var i = 0
+    while (i < line.length) {
+        val cp = line.codePointAt(i)
+        val width = Character.charCount(cp)
+        val piece = line.substring(i, i + width)
+        val pieceOctets = piece.toByteArray(Charsets.UTF_8).size
+        // Continuation lines spend one octet on the leading space.
+        val budget = if (first) MAX_OCTETS else MAX_OCTETS - 1
+        if (octetsThisLine + pieceOctets > budget) {
+            out.append(ICS_CRLF).append(' ')
+            octetsThisLine = 0
+            first = false
+        }
+        out.append(piece)
+        octetsThisLine += pieceOctets
+        i += width
+    }
+    return out.toString()
+}
+
+/**
+ * Reverse of [escapeText]: turn `\n`/`\N` into newlines and unescape `\\`, `\;`,
+ * `\,`. A backslash before any other character is dropped, keeping the
+ * character (lenient — foreign files escape liberally).
+ */
+fun unescapeText(value: String): String = buildString(value.length) {
+    var i = 0
+    while (i < value.length) {
+        val c = value[i]
+        if (c == '\\' && i + 1 < value.length) {
+            when (val next = value[i + 1]) {
+                'n', 'N' -> append('\n')
+                else -> append(next) // \\, \;, \, and any other escaped char
+            }
+            i += 2
+        } else {
+            append(c)
+            i++
+        }
+    }
+}
+
+/**
+ * Reverse of [foldLine] across a whole document: split into physical lines on
+ * CRLF/LF/CR, then re-join any line that begins with a single space or tab onto
+ * the previous one (RFC 5545 unfolding). Returns the logical content lines.
+ */
+fun unfoldLines(text: String): List<String> {
+    val out = mutableListOf<String>()
+    for (physical in text.split("\r\n", "\n", "\r")) {
+        if (physical.isEmpty()) continue
+        val isContinuation = physical[0] == ' ' || physical[0] == '\t'
+        if (isContinuation && out.isNotEmpty()) {
+            out[out.lastIndex] = out.last() + physical.substring(1)
+        } else {
+            out.add(physical)
+        }
+    }
+    return out
+}
+
+/**
+ * One unfolded content line split into its property name, parameters and value:
+ * `SUMMARY;LANGUAGE=en:Lunch` → name `SUMMARY`, params `{LANGUAGE=en}`, value
+ * `Lunch`. The value is everything after the first colon that isn't inside a
+ * quoted parameter; param keys are upper-cased, quoted param values unquoted.
+ * Returns null for a line with no colon.
+ */
+data class IcsContentLine(val name: String, val params: Map<String, String>, val value: String)
+
+fun parseContentLine(line: String): IcsContentLine? {
+    var inQuote = false
+    var colon = -1
+    for (i in line.indices) {
+        when (line[i]) {
+            '"' -> inQuote = !inQuote
+            ':' -> if (!inQuote) { colon = i; break }
+        }
+    }
+    if (colon < 0) return null
+    val head = splitUnquoted(line.substring(0, colon), ';')
+    val name = head.firstOrNull()?.trim()?.uppercase().orEmpty()
+    if (name.isEmpty()) return null
+    val params = buildMap {
+        for (part in head.drop(1)) {
+            val eq = part.indexOf('=')
+            if (eq > 0) {
+                put(
+                    part.substring(0, eq).trim().uppercase(),
+                    part.substring(eq + 1).trim().removeSurrounding("\""),
+                )
+            }
+        }
+    }
+    return IcsContentLine(name, params, line.substring(colon + 1))
+}
+
+/** Split on [delimiter] except where it falls inside a double-quoted run. */
+private fun splitUnquoted(text: String, delimiter: Char): List<String> {
+    val parts = mutableListOf<String>()
+    val current = StringBuilder()
+    var inQuote = false
+    for (c in text) {
+        when {
+            c == '"' -> { inQuote = !inQuote; current.append(c) }
+            c == delimiter && !inQuote -> { parts.add(current.toString()); current.clear() }
+            else -> current.append(c)
+        }
+    }
+    parts.add(current.toString())
+    return parts
+}

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/IcsWriter.kt

@@ -0,0 +1,124 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import de.jeanlucmakiola.calendula.domain.Availability
+import de.jeanlucmakiola.calendula.domain.EventStatus
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.number
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Instant
+
+/** Default `PRODID` advertising the writer that produced the file. */
+const val ICS_PROD_ID: String = "-//Jean-Luc Makiola//Calendula//EN"
+
+/**
+ * Hand-rolled RFC 5545 serialiser for the subset Calendula models. No iCal
+ * library: we stay on `kotlinx-datetime` and own the output, exactly as
+ * `domain/Recurrence.kt` owns RRULE. Pure and JVM-testable — the caller
+ * supplies [dtStamp] (the export moment) so the writer never reads a clock.
+ *
+ * Timezone rule (see plan 05, decision 1):
+ *  - all-day      → `VALUE=DATE`, no zone;
+ *  - timed one-off → UTC instant with a `Z` suffix (an instant is an instant);
+ *  - timed recurring → `TZID`-labelled local wall time, so the series stays
+ *    anchored to wall-clock across DST. No `VTIMEZONE` block is emitted; import
+ *    resolves the `TZID` against the OS tz database.
+ */
+class IcsWriter(private val prodId: String = ICS_PROD_ID) {
+
+    fun writeCalendar(events: List<IcsEvent>, dtStamp: Instant): String {
+        val lines = buildList {
+            add("BEGIN:VCALENDAR")
+            add("VERSION:2.0")
+            add("PRODID:$prodId")
+            add("CALSCALE:GREGORIAN")
+            events.forEach { appendEvent(it, dtStamp) }
+            add("END:VCALENDAR")
+        }
+        return lines.joinToString(ICS_CRLF, postfix = ICS_CRLF) { foldLine(it) }
+    }
+
+    private fun MutableList<String>.appendEvent(event: IcsEvent, dtStamp: Instant) {
+        add("BEGIN:VEVENT")
+        add("UID:${event.uid}")
+        add("DTSTAMP:${utcStamp(dtStamp)}")
+        add("SUMMARY:${escapeText(event.summary)}")
+        appendTimes(event)
+        event.recurrenceRule?.takeIf { it.isNotBlank() }
+            ?.let { add("RRULE:${it.removePrefix("RRULE:")}") }
+        event.location?.takeIf { it.isNotBlank() }
+            ?.let { add("LOCATION:${escapeText(it)}") }
+        event.description?.takeIf { it.isNotBlank() }
+            ?.let { add("DESCRIPTION:${escapeText(it)}") }
+        add("STATUS:${statusValue(event.status)}")
+        add("TRANSP:${transpValue(event.availability)}")
+        event.calendarName?.takeIf { it.isNotBlank() }
+            ?.let { add("X-CALENDULA-CALENDAR:${escapeText(it)}") }
+        event.reminderMinutes.filter { it >= 0 }.distinct().forEach { minutes ->
+            appendAlarm(minutes, event.summary)
+        }
+        add("END:VEVENT")
+    }
+
+    private fun MutableList<String>.appendTimes(event: IcsEvent) = when {
+        event.isAllDay -> {
+            add("DTSTART;VALUE=DATE:${utcDate(event.start)}")
+            add("DTEND;VALUE=DATE:${utcDate(event.end)}")
+        }
+        // Recurring: anchor to wall-clock in the event's own zone.
+        event.recurrenceRule?.isNotBlank() == true -> {
+            val zone = runCatching { TimeZone.of(event.zoneId) }.getOrNull()
+            if (zone != null) {
+                add("DTSTART;TZID=${event.zoneId}:${localStamp(event.start, zone)}")
+                add("DTEND;TZID=${event.zoneId}:${localStamp(event.end, zone)}")
+            } else {
+                // Unknown zone id → fall back to plain UTC instants.
+                add("DTSTART:${utcStamp(event.start)}")
+                add("DTEND:${utcStamp(event.end)}")
+            }
+        }
+        else -> {
+            add("DTSTART:${utcStamp(event.start)}")
+            add("DTEND:${utcStamp(event.end)}")
+        }
+    }
+
+    private fun MutableList<String>.appendAlarm(minutes: Int, summary: String) {
+        add("BEGIN:VALARM")
+        add("ACTION:DISPLAY")
+        add("DESCRIPTION:${escapeText(summary.ifBlank { "Reminder" })}")
+        add("TRIGGER:${triggerValue(minutes)}")
+        add("END:VALARM")
+    }
+
+    private companion object {
+        fun statusValue(status: EventStatus): String = when (status) {
+            EventStatus.Confirmed -> "CONFIRMED"
+            EventStatus.Tentative -> "TENTATIVE"
+            EventStatus.Cancelled -> "CANCELLED"
+        }
+
+        // iCal TRANSP is binary; only an explicitly free event is TRANSPARENT.
+        fun transpValue(availability: Availability): String =
+            if (availability == Availability.Free) "TRANSPARENT" else "OPAQUE"
+
+        // A lead time of 0 fires at start (PT0M); anything positive is "before".
+        fun triggerValue(minutes: Int): String =
+            if (minutes <= 0) "PT0M" else "-PT${minutes}M"
+
+        fun utcStamp(instant: Instant): String =
+            basic(instant.toLocalDateTime(TimeZone.UTC)) + "Z"
+
+        fun localStamp(instant: Instant, zone: TimeZone): String =
+            basic(instant.toLocalDateTime(zone))
+
+        fun utcDate(instant: Instant): String {
+            val dt = instant.toLocalDateTime(TimeZone.UTC)
+            return "%04d%02d%02d".format(dt.year, dt.month.number, dt.day)
+        }
+
+        fun basic(dt: LocalDateTime): String = "%04d%02d%02dT%02d%02d%02d".format(
+            dt.year, dt.month.number, dt.day, dt.hour, dt.minute, dt.second,
+        )
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/ParsedIcsForm.kt

@@ -0,0 +1,38 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import de.jeanlucmakiola.calendula.domain.EventForm
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+
+/**
+ * Prefill the create form from a single parsed `.ics` event (the "open one
+ * event" path). [calendarId] is left null so the form preselects the last-used
+ * calendar, exactly like a fresh create — the user confirms the target and
+ * reviews everything before saving. Mirrors `EventDetail.toEditForm`'s all-day
+ * handling (provider all-day times are UTC midnights with an exclusive end).
+ */
+fun ParsedIcsEvent.toEventForm(zone: TimeZone): EventForm {
+    val (start, end) = if (isAllDay) {
+        val startDate = this.start.toLocalDateTime(TimeZone.UTC).date
+        val endExclusive = this.end.toLocalDateTime(TimeZone.UTC).date
+        val endDate = maxOf(startDate, LocalDate.fromEpochDays(endExclusive.toEpochDays() - 1))
+        LocalDateTime(startDate, LocalTime(9, 0)) to LocalDateTime(endDate, LocalTime(10, 0))
+    } else {
+        this.start.toLocalDateTime(zone) to this.end.toLocalDateTime(zone)
+    }
+    return EventForm(
+        calendarId = null,
+        title = summary,
+        isAllDay = isAllDay,
+        start = start,
+        end = end,
+        location = location.orEmpty(),
+        description = description.orEmpty(),
+        reminders = reminderMinutes.distinct().sorted(),
+        availability = availability,
+        rrule = recurrenceRule?.removePrefix("RRULE:")?.takeIf { it.isNotBlank() },
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/CalendarHost.kt

@@ -1,41 +1,295 @@
 package de.jeanlucmakiola.calendula.ui
 
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.slideInHorizontally
+import androidx.compose.animation.slideOutHorizontally
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
+import de.jeanlucmakiola.calendula.domain.EventForm
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.ui.agenda.AgendaScreen
+import de.jeanlucmakiola.calendula.ui.calendars.CalendarsScreen
 import de.jeanlucmakiola.calendula.ui.common.CalendarView
+import de.jeanlucmakiola.calendula.ui.common.rememberCalendarSlideSpec
 import de.jeanlucmakiola.calendula.ui.day.DayScreen
+import de.jeanlucmakiola.calendula.ui.detail.EventDetailScreen
+import de.jeanlucmakiola.calendula.ui.edit.EventEditScreen
+import de.jeanlucmakiola.calendula.ui.imports.ImportScreen
 import de.jeanlucmakiola.calendula.ui.month.MonthScreen
+import de.jeanlucmakiola.calendula.ui.settings.SettingsScreen
 import de.jeanlucmakiola.calendula.ui.week.WeekScreen
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Clock
 
 /**
  * Holds the active top-level view (spec M1) and swaps between the calendar
  * screens. Each screen owns its own ViewModel and date anchor; the view-switcher
  * pill in their top bars writes back here via [onSelectView].
+ *
+ * [requestedDetailKey] is an externally requested occurrence (a tapped
+ * reminder notification routed through MainActivity): it opens the detail
+ * overlay exactly like an event tap and is cleared via [onDetailKeyConsumed]
+ * so a later recomposition can't re-open it.
  */
 @Composable
-fun CalendarHost(modifier: Modifier = Modifier) {
-    var view by rememberSaveable { mutableStateOf(CalendarView.Month) }
+fun CalendarHost(
+    modifier: Modifier = Modifier,
+    requestedDetailKey: LongArray? = null,
+    onDetailKeyConsumed: () -> Unit = {},
+    widgetNavRequest: WidgetNavRequest? = null,
+    onWidgetNavConsumed: () -> Unit = {},
+    requestedImportUri: android.net.Uri? = null,
+    onImportConsumed: () -> Unit = {},
+) {
+    var view by rememberSaveable { mutableStateOf(CalendarView.Week) }
     val onSelectView: (CalendarView) -> Unit = { view = it }
 
+    // Tapping a day in the month grid opens the day view anchored to that date.
+    var pendingDayIso by rememberSaveable { mutableStateOf<String?>(null) }
+    val onOpenDay: (LocalDate) -> Unit = { date ->
+        pendingDayIso = date.toString()
+        view = CalendarView.Day
+    }
+
+    // The event-detail screen (S4) is a full-screen destination hoisted here so
+    // it overlays whichever calendar view is active. We forward the tapped
+    // occurrence's own times (eventId + begin + end, packed as a saveable
+    // long[]) so recurring events show the correct date, not the series start.
+    // [heldKey] keeps the last shown key alive through the slide-out (when
+    // [detailKey] is cleared); it is set in the tap callback — never a [0,0,0]
+    // placeholder — so the destination never loads a bogus id=0 on first frame.
+    var detailKey by rememberSaveable { mutableStateOf<LongArray?>(null) }
+    var heldKey by remember { mutableStateOf<LongArray?>(null) }
+    val onEventClick: (EventInstance) -> Unit = { event ->
+        val key = longArrayOf(
+            event.eventId,
+            event.start.toEpochMilliseconds(),
+            event.end.toEpochMilliseconds(),
+        )
+        heldKey = key
+        detailKey = key
+    }
+
+    // A tapped reminder notification asks for a specific occurrence.
+    LaunchedEffect(requestedDetailKey) {
+        if (requestedDetailKey != null) {
+            heldKey = requestedDetailKey
+            detailKey = requestedDetailKey
+            onDetailKeyConsumed()
+        }
+    }
+
+    // Settings (M4) is hoisted here so it overlays whichever calendar view is
+    // active and survives view switches. (The calendar filter now lives inline
+    // in the navigation drawer, so no overlay state is needed for it.)
+    var showSettings by rememberSaveable { mutableStateOf(false) }
+    val onOpenSettings = { showSettings = true }
+
+    // Calendar manager (reached from Settings) — its own overlay so it slides
+    // over Settings and survives view switches.
+    var showCalendars by rememberSaveable { mutableStateOf(false) }
+
+    // Event form (v1.2 create) — same held-key pattern as the detail screen:
+    // [heldCreateIso] keeps the prefill date alive through the slide-out.
+    // [createStartMinutes] is the tapped slot's start (minutes from midnight)
+    // when the form is opened from a day/week grid tap; null from the FAB.
+    var createDateIso by rememberSaveable { mutableStateOf<String?>(null) }
+    var heldCreateIso by remember { mutableStateOf<String?>(null) }
+    var createStartMinutes by rememberSaveable { mutableStateOf<Int?>(null) }
+    var heldCreateMinutes by remember { mutableStateOf<Int?>(null) }
+    val onCreateEvent: (LocalDate, Int?) -> Unit = { date, startMinutes ->
+        heldCreateIso = date.toString()
+        createDateIso = date.toString()
+        heldCreateMinutes = startMinutes
+        createStartMinutes = startMinutes
+    }
+
+    // Edit form (v1.3) — reuses the detail screen's occurrence key; for
+    // recurring events the form itself asks for the write scope at save
+    // time. A saved edit closes the detail screen too: the occurrence the
+    // user tapped may not exist anymore (time moved, recurrence changed), so
+    // falling back to the auto-refreshing calendar is the only honest
+    // destination.
+    var editKey by rememberSaveable { mutableStateOf<LongArray?>(null) }
+    var heldEditKey by remember { mutableStateOf<LongArray?>(null) }
+
+    // An opened/received .ics file. [ImportScreen] parses it and either opens
+    // the prefilled create form (one event → [importForm]) or its own bulk
+    // picker (many). A plain conditional overlay (no slide) — it's transient.
+    var importUri by remember { mutableStateOf<android.net.Uri?>(null) }
+    var importForm by remember { mutableStateOf<EventForm?>(null) }
+    LaunchedEffect(requestedImportUri) {
+        if (requestedImportUri != null) {
+            importUri = requestedImportUri
+            onImportConsumed()
+        }
+    }
+
+    // A home-screen widget launch asks to open a date (→ day view) or start a
+    // create. Handled once and cleared, mirroring [requestedDetailKey].
+    LaunchedEffect(widgetNavRequest) {
+        when (val req = widgetNavRequest) {
+            is WidgetNavRequest.OpenDate -> {
+                pendingDayIso = req.dateIso
+                view = CalendarView.Day
+                onWidgetNavConsumed()
+            }
+            is WidgetNavRequest.Create -> {
+                val iso = req.dateIso ?: Clock.System.now()
+                    .toLocalDateTime(TimeZone.currentSystemDefault()).date.toString()
+                heldCreateIso = iso
+                createDateIso = iso
+                heldCreateMinutes = null
+                createStartMinutes = null
+                onWidgetNavConsumed()
+            }
+            null -> {}
+        }
+    }
+
+    val slideSpec = rememberCalendarSlideSpec()
+
+    Box(modifier = modifier.fillMaxSize()) {
         when (view) {
             CalendarView.Week -> WeekScreen(
                 selectedView = view,
                 onSelectView = onSelectView,
-            modifier = modifier,
+                onEventClick = onEventClick,
+                onOpenSettings = onOpenSettings,
+                onCreateEvent = onCreateEvent,
             )
             CalendarView.Day -> DayScreen(
                 selectedView = view,
                 onSelectView = onSelectView,
-            modifier = modifier,
+                onEventClick = onEventClick,
+                onOpenSettings = onOpenSettings,
+                onCreateEvent = onCreateEvent,
+                initialDateIso = pendingDayIso,
             )
             CalendarView.Month -> MonthScreen(
                 selectedView = view,
                 onSelectView = onSelectView,
-            modifier = modifier,
+                onOpenDay = onOpenDay,
+                onOpenSettings = onOpenSettings,
+                onCreateEvent = onCreateEvent,
+            )
+            CalendarView.Agenda -> AgendaScreen(
+                selectedView = view,
+                onSelectView = onSelectView,
+                onEventClick = onEventClick,
+                onOpenSettings = onOpenSettings,
+                onCreateEvent = onCreateEvent,
+            )
+        }
+
+        // Prefer the live key; fall back to the held one only while sliding out.
+        val activeKey = detailKey ?: heldKey
+        AnimatedVisibility(
+            visible = detailKey != null,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            activeKey?.let { key ->
+                EventDetailScreen(
+                    eventId = key[0],
+                    beginMillis = key[1],
+                    endMillis = key[2],
+                    onBack = { detailKey = null },
+                    onEdit = {
+                        heldEditKey = key
+                        editKey = key
+                    },
                 )
             }
         }
+
+        // Event form (v1.2) — full-screen destination, slides over the calendar.
+        AnimatedVisibility(
+            visible = createDateIso != null,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            (createDateIso ?: heldCreateIso)?.let { iso ->
+                EventEditScreen(
+                    initialDateIso = iso,
+                    initialStartMinutes = createStartMinutes ?: heldCreateMinutes,
+                    onClose = { createDateIso = null },
+                    onSaved = { createDateIso = null },
+                )
+            }
+        }
+
+        // Edit form (v1.3) — slides over the detail screen.
+        AnimatedVisibility(
+            visible = editKey != null,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            (editKey ?: heldEditKey)?.let { key ->
+                EventEditScreen(
+                    initialDateIso = null,
+                    editKey = key,
+                    onClose = { editKey = null },
+                    onSaved = {
+                        editKey = null
+                        detailKey = null
+                    },
+                )
+            }
+        }
+
+        // Settings (M4) — full-screen destination, slides over the calendar.
+        AnimatedVisibility(
+            visible = showSettings,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            SettingsScreen(
+                onBack = { showSettings = false },
+                onManageCalendars = { showCalendars = true },
+            )
+        }
+
+        // Calendar manager — slides over Settings.
+        AnimatedVisibility(
+            visible = showCalendars,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            CalendarsScreen(onBack = { showCalendars = false })
+        }
+
+        // Import flow for an opened/received .ics file. A single event routes
+        // into the create form (prefilled, for review); many open the picker.
+        importUri?.let { uri ->
+            ImportScreen(
+                uri = uri,
+                onClose = { importUri = null },
+                onOpenSingle = { form ->
+                    importUri = null
+                    importForm = form
+                },
+            )
+        }
+        importForm?.let { form ->
+            EventEditScreen(
+                initialDateIso = null,
+                initialForm = form,
+                onClose = { importForm = null },
+                onSaved = { importForm = null },
+            )
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/RootScreen.kt

@@ -10,14 +10,26 @@ import androidx.compose.runtime.setValue
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
+import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.LocalLifecycleOwner
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.core.content.ContextCompat
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.LifecycleEventObserver
 import de.jeanlucmakiola.calendula.ui.permission.PermissionScreen
+import de.jeanlucmakiola.calendula.ui.permission.ReminderOnboardingScreen
+import de.jeanlucmakiola.calendula.ui.permission.ReminderOnboardingViewModel
 
 @Composable
-fun RootScreen(modifier: Modifier = Modifier) {
+fun RootScreen(
+    modifier: Modifier = Modifier,
+    requestedDetailKey: LongArray? = null,
+    onDetailKeyConsumed: () -> Unit = {},
+    widgetNavRequest: WidgetNavRequest? = null,
+    onWidgetNavConsumed: () -> Unit = {},
+    requestedImportUri: android.net.Uri? = null,
+    onImportConsumed: () -> Unit = {},
+) {
     val context = LocalContext.current
     var hasPermission by remember {
         mutableStateOf(
@@ -40,7 +52,27 @@ fun RootScreen(modifier: Modifier = Modifier) {
     }
 
     if (hasPermission) {
-        CalendarHost(modifier = modifier)
+        // Second onboarding gate (v1.4, one-time): reminder notifications.
+        // Null until DataStore's first emission — render nothing for that
+        // frame instead of flashing the wrong screen.
+        val reminderOnboarding: ReminderOnboardingViewModel = hiltViewModel()
+        val onboardingDone by reminderOnboarding.onboardingDone.collectAsStateWithLifecycle()
+        when (onboardingDone) {
+            true -> CalendarHost(
+                modifier = modifier,
+                requestedDetailKey = requestedDetailKey,
+                onDetailKeyConsumed = onDetailKeyConsumed,
+                widgetNavRequest = widgetNavRequest,
+                onWidgetNavConsumed = onWidgetNavConsumed,
+                requestedImportUri = requestedImportUri,
+                onImportConsumed = onImportConsumed,
+            )
+            false -> ReminderOnboardingScreen(
+                onFinished = reminderOnboarding::finish,
+                modifier = modifier,
+            )
+            null -> {}
+        }
     } else {
         PermissionScreen(
             onGranted = { hasPermission = true },

app/src/main/java/de/jeanlucmakiola/calendula/ui/WidgetNavRequest.kt

@@ -0,0 +1,15 @@
+package de.jeanlucmakiola.calendula.ui
+
+/**
+ * A navigation a home-screen widget asked the app to perform when launched.
+ * Parsed from the launch intent in MainActivity and consumed once by
+ * [CalendarHost] (event taps reuse the existing reminder detail-key channel, so
+ * they are not modelled here).
+ */
+sealed interface WidgetNavRequest {
+    /** Open the day view anchored on [dateIso] (an ISO `yyyy-MM-dd` date). */
+    data class OpenDate(val dateIso: String) : WidgetNavRequest
+
+    /** Open the create-event form prefilled for [dateIso] (today when null). */
+    data class Create(val dateIso: String?) : WidgetNavRequest
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaScreen.kt

@@ -0,0 +1,344 @@
+package de.jeanlucmakiola.calendula.ui.agenda
+
+import androidx.compose.foundation.ExperimentalFoundationApi
+import androidx.compose.foundation.background
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.itemsIndexed
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.EventAvailable
+import androidx.compose.material.icons.filled.Menu
+import androidx.compose.material3.DrawerValue
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.ModalNavigationDrawer
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.TopAppBarDefaults
+import androidx.compose.material3.TopAppBarScrollBehavior
+import androidx.compose.material3.rememberDrawerState
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.input.nestedscroll.nestedScroll
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.ui.common.CalendarDrawer
+import de.jeanlucmakiola.calendula.ui.common.CalendarFabColumn
+import de.jeanlucmakiola.calendula.ui.common.CalendarFailure
+import de.jeanlucmakiola.calendula.ui.common.CalendarView
+import de.jeanlucmakiola.calendula.ui.common.GroupedRow
+import de.jeanlucmakiola.calendula.ui.common.Position
+import de.jeanlucmakiola.calendula.ui.common.ViewSwitcherPill
+import de.jeanlucmakiola.calendula.ui.common.next
+import de.jeanlucmakiola.calendula.ui.common.pastelize
+import de.jeanlucmakiola.calendula.ui.common.positionOf
+import kotlinx.coroutines.launch
+import kotlinx.datetime.DateTimeUnit
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.plus
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Instant
+import java.time.format.TextStyle as JavaTextStyle
+import java.util.Locale
+
+private val zone = TimeZone.currentSystemDefault()
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun AgendaScreen(
+    selectedView: CalendarView,
+    onSelectView: (CalendarView) -> Unit,
+    onEventClick: (EventInstance) -> Unit,
+    onOpenSettings: () -> Unit,
+    onCreateEvent: (LocalDate, Int?) -> Unit,
+    modifier: Modifier = Modifier,
+    viewModel: AgendaViewModel = hiltViewModel(),
+) {
+    val state by viewModel.state.collectAsStateWithLifecycle()
+    val anchor by viewModel.anchor.collectAsStateWithLifecycle()
+
+    val scrollBehavior = TopAppBarDefaults.pinnedScrollBehavior()
+    val drawerState = rememberDrawerState(DrawerValue.Closed)
+    val scope = rememberCoroutineScope()
+
+    val isOnToday = when (val s = state) {
+        is AgendaUiState.Success -> s.anchor == s.today
+        else -> true
+    }
+
+    ModalNavigationDrawer(
+        drawerState = drawerState,
+        drawerContent = {
+            CalendarDrawer(
+                currentView = selectedView,
+                currentDate = anchor,
+                onSelectView = { view ->
+                    onSelectView(view)
+                    scope.launch { drawerState.close() }
+                },
+                onJumpToDate = { target ->
+                    viewModel.goToDate(target)
+                    scope.launch { drawerState.close() }
+                },
+                onSettings = {
+                    onOpenSettings()
+                    scope.launch { drawerState.close() }
+                },
+            )
+        },
+    ) {
+        Scaffold(
+            modifier = modifier.nestedScroll(scrollBehavior.nestedScrollConnection),
+            topBar = {
+                AgendaTopBar(
+                    selectedView = selectedView,
+                    onCycleView = { onSelectView(selectedView.next()) },
+                    onOpenDrawer = { scope.launch { drawerState.open() } },
+                    scrollBehavior = scrollBehavior,
+                )
+            },
+            floatingActionButton = {
+                CalendarFabColumn(
+                    todayVisible = !isOnToday,
+                    todayText = stringResource(R.string.agenda_today_action),
+                    onToday = viewModel::goToToday,
+                    onCreate = { onCreateEvent(anchor, null) },
+                )
+            },
+        ) { innerPadding ->
+            AgendaContent(
+                state = state,
+                onRetry = viewModel::goToToday,
+                onEventClick = onEventClick,
+                modifier = Modifier
+                    .padding(innerPadding)
+                    .fillMaxSize(),
+            )
+        }
+    }
+}
+
+@Composable
+private fun AgendaContent(
+    state: AgendaUiState,
+    onRetry: () -> Unit,
+    onEventClick: (EventInstance) -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    when (state) {
+        AgendaUiState.Loading -> Box(modifier)
+        is AgendaUiState.Failure -> Box(modifier) {
+            CalendarFailure(reason = state.reason, onRetry = onRetry)
+        }
+        is AgendaUiState.Success ->
+            if (state.days.isEmpty()) {
+                AgendaEmpty(modifier)
+            } else {
+                AgendaList(state = state, onEventClick = onEventClick, modifier = modifier)
+            }
+    }
+}
+
+@OptIn(ExperimentalFoundationApi::class)
+@Composable
+private fun AgendaList(
+    state: AgendaUiState.Success,
+    onEventClick: (EventInstance) -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    LazyColumn(
+        modifier = modifier,
+        // Bottom inset clears the FAB stack so the last row stays tappable.
+        contentPadding = PaddingValues(top = 8.dp, bottom = 96.dp),
+    ) {
+        state.days.forEach { day ->
+            stickyHeader(key = "header-${day.date}") {
+                AgendaDayHeader(date = day.date, today = state.today)
+            }
+            itemsIndexed(
+                items = day.events,
+                key = { _, event -> event.instanceId },
+            ) { index, event ->
+                AgendaEventRow(
+                    event = event,
+                    position = positionOf(index, day.events.size),
+                    onClick = { onEventClick(event) },
+                )
+            }
+            item(key = "gap-${day.date}") { Spacer(Modifier.height(8.dp)) }
+        }
+    }
+}
+
+@Composable
+private fun AgendaDayHeader(date: LocalDate, today: LocalDate) {
+    Surface(
+        color = MaterialTheme.colorScheme.surface,
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Text(
+            text = agendaDayLabel(date, today),
+            style = MaterialTheme.typography.titleSmall,
+            color = if (date == today) {
+                MaterialTheme.colorScheme.primary
+            } else {
+                MaterialTheme.colorScheme.onSurfaceVariant
+            },
+            modifier = Modifier.padding(start = 28.dp, end = 28.dp, top = 16.dp, bottom = 8.dp),
+        )
+    }
+}
+
+@Composable
+private fun AgendaEventRow(
+    event: EventInstance,
+    position: Position,
+    onClick: () -> Unit,
+) {
+    val dark = isSystemInDarkTheme()
+    val title = event.title.ifBlank { stringResource(R.string.event_untitled) }
+    GroupedRow(
+        title = title,
+        summary = agendaTimeSummary(event),
+        position = position,
+        minHeight = 64.dp,
+        leading = {
+            Box(
+                modifier = Modifier
+                    .size(width = 6.dp, height = 36.dp)
+                    .clip(RoundedCornerShape(3.dp))
+                    .background(pastelize(event.color, dark)),
+            )
+        },
+        onClick = onClick,
+    )
+}
+
+@Composable
+private fun AgendaEmpty(modifier: Modifier = Modifier) {
+    Column(
+        modifier = modifier.padding(32.dp),
+        verticalArrangement = Arrangement.Center,
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        Icon(
+            imageVector = Icons.Filled.EventAvailable,
+            contentDescription = null,
+            tint = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.size(48.dp),
+        )
+        Spacer(Modifier.height(16.dp))
+        Text(
+            text = stringResource(R.string.agenda_empty_title),
+            style = MaterialTheme.typography.titleMedium,
+            textAlign = TextAlign.Center,
+        )
+        Spacer(Modifier.height(4.dp))
+        Text(
+            text = stringResource(R.string.agenda_empty_subtitle),
+            style = MaterialTheme.typography.bodyMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            textAlign = TextAlign.Center,
+        )
+    }
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun AgendaTopBar(
+    selectedView: CalendarView,
+    onCycleView: () -> Unit,
+    onOpenDrawer: () -> Unit,
+    scrollBehavior: TopAppBarScrollBehavior,
+) {
+    TopAppBar(
+        title = {
+            Text(
+                text = stringResource(R.string.view_agenda),
+                style = MaterialTheme.typography.titleLarge,
+            )
+        },
+        navigationIcon = {
+            IconButton(onClick = onOpenDrawer) {
+                Icon(
+                    imageVector = Icons.Default.Menu,
+                    contentDescription = stringResource(R.string.month_open_menu),
+                )
+            }
+        },
+        actions = {
+            ViewSwitcherPill(
+                current = selectedView,
+                onCycle = onCycleView,
+                modifier = Modifier.padding(end = 8.dp),
+            )
+        },
+        colors = TopAppBarDefaults.topAppBarColors(
+            containerColor = MaterialTheme.colorScheme.surface,
+            scrolledContainerColor = MaterialTheme.colorScheme.surfaceContainer,
+        ),
+        scrollBehavior = scrollBehavior,
+    )
+}
+
+/** "Today · Wed, 17. Jun 2026" — relative word for today/tomorrow, else the date. */
+@Composable
+private fun agendaDayLabel(date: LocalDate, today: LocalDate): String {
+    val relative = when (date) {
+        today -> stringResource(R.string.agenda_header_today)
+        today.plus(1, DateTimeUnit.DAY) -> stringResource(R.string.agenda_header_tomorrow)
+        else -> null
+    }
+    val formatted = formatAgendaDate(date)
+    return if (relative != null) "$relative · $formatted" else formatted
+}
+
+/** Time line under the title: "09:00 – 10:00 · Location", "All day", etc. */
+@Composable
+private fun agendaTimeSummary(event: EventInstance): String {
+    val time = if (event.isAllDay) {
+        stringResource(R.string.event_detail_all_day)
+    } else {
+        "${formatTime(event.start)} – ${formatTime(event.end)}"
+    }
+    val location = event.location?.takeIf { it.isNotBlank() }
+    return if (location != null) "$time · $location" else time
+}
+
+private fun formatTime(instant: Instant): String {
+    val t = instant.toLocalDateTime(zone).time
+    return "%02d:%02d".format(t.hour, t.minute)
+}
+
+private fun formatAgendaDate(date: LocalDate): String {
+    val locale = Locale.getDefault()
+    val java = java.time.LocalDate.of(date.year, date.month.ordinal + 1, date.day)
+    val weekday = java.dayOfWeek.getDisplayName(JavaTextStyle.SHORT, locale)
+    val monthName = java.month.getDisplayName(JavaTextStyle.SHORT, locale)
+    return "$weekday, ${date.day}. $monthName ${date.year}"
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaUiState.kt

@@ -0,0 +1,57 @@
+package de.jeanlucmakiola.calendula.ui.agenda
+
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.FailureReason
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
+
+/** One calendar day with at least one event, for the agenda list. */
+data class AgendaDay(
+    val date: LocalDate,
+    /** Events on this day, all-day first then ascending by start time. */
+    val events: List<EventInstance>,
+)
+
+/**
+ * Group flat [instances] into forward-looking [AgendaDay]s (only days that
+ * actually carry events). An event that began before [anchor] (ongoing or
+ * multi-day) is clamped to the anchor day so it still surfaces on top. Within a
+ * day, all-day events sort first, then ascending by start time, then title.
+ *
+ * Shared by the Agenda screen and the agenda home-screen widget so both group
+ * and order identically.
+ */
+fun groupAgendaDays(
+    anchor: LocalDate,
+    instances: List<EventInstance>,
+    zone: TimeZone,
+): List<AgendaDay> =
+    instances
+        .groupBy { it.start.toLocalDateTime(zone).date.coerceAtLeast(anchor) }
+        .toSortedMap()
+        .map { (date, dayEvents) ->
+            AgendaDay(
+                date = date,
+                events = dayEvents.sortedWith(
+                    compareByDescending<EventInstance> { it.isAllDay }
+                        .thenBy { it.start }
+                        .thenBy { it.title },
+                ),
+            )
+        }
+
+/**
+ * State for the Agenda view: a flat, forward-looking list of upcoming events
+ * grouped by day (only days that actually have events appear).
+ */
+sealed interface AgendaUiState {
+    data object Loading : AgendaUiState
+    data class Failure(val reason: FailureReason) : AgendaUiState
+    data class Success(
+        /** First day of the loaded window (today, or a jumped-to date). */
+        val anchor: LocalDate,
+        val today: LocalDate,
+        val days: List<AgendaDay>,
+    ) : AgendaUiState
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaViewModel.kt

@@ -0,0 +1,96 @@
+package de.jeanlucmakiola.calendula.ui.agenda
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.FailureReason
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.datetime.DateTimeUnit
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.atStartOfDayIn
+import kotlinx.datetime.atTime
+import kotlinx.datetime.plus
+import kotlinx.datetime.toInstant
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Clock
+import kotlin.time.Instant
+import javax.inject.Inject
+
+/** How far ahead the agenda loads events from its anchor day. */
+internal const val AGENDA_WINDOW_DAYS = 60
+
+@OptIn(ExperimentalCoroutinesApi::class)
+@HiltViewModel
+class AgendaViewModel @Inject constructor(
+    private val repository: CalendarRepository,
+    @IoDispatcher private val io: CoroutineDispatcher,
+) : ViewModel() {
+
+    private val zone = TimeZone.currentSystemDefault()
+
+    private val todayDate: LocalDate
+        get() = Clock.System.now().toLocalDateTime(zone).date
+
+    private val _anchor = MutableStateFlow(todayDate)
+    val anchor: StateFlow<LocalDate> = _anchor
+
+    val state: StateFlow<AgendaUiState> = _anchor
+        .flatMapLatest { anchor ->
+            val range = agendaRange(anchor, AGENDA_WINDOW_DAYS, zone)
+            combine(
+                repository.calendars(),
+                repository.instances(range),
+            ) { calendars, instances ->
+                buildState(anchor, calendars, instances)
+            }
+        }
+        .catch { emit(AgendaUiState.Failure(FailureReason.ProviderUnavailable)) }
+        .flowOn(io)
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = AgendaUiState.Loading,
+        )
+
+    fun goToToday() {
+        _anchor.value = todayDate
+    }
+
+    /** Jump the agenda window to start on a specific date (drawer jump-to-date). */
+    fun goToDate(date: LocalDate) {
+        _anchor.value = date
+    }
+
+    private fun buildState(
+        anchor: LocalDate,
+        calendars: List<CalendarSource>,
+        instances: List<EventInstance>,
+    ): AgendaUiState {
+        if (calendars.isEmpty()) {
+            return AgendaUiState.Failure(FailureReason.NoCalendarsConfigured)
+        }
+        val days = groupAgendaDays(anchor, instances, zone)
+        return AgendaUiState.Success(anchor = anchor, today = todayDate, days = days)
+    }
+}
+
+/** Inclusive instant range from the start of [anchor] through [days] days ahead. */
+internal fun agendaRange(anchor: LocalDate, days: Int, zone: TimeZone): ClosedRange<Instant> {
+    val from = anchor.atStartOfDayIn(zone)
+    val to = anchor.plus(days, DateTimeUnit.DAY).atTime(23, 59, 59).toInstant(zone)
+    return from..to
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/calendars/CalendarsScreen.kt

@@ -0,0 +1,571 @@
+package de.jeanlucmakiola.calendula.ui.calendars
+
+import android.accounts.AccountManager
+import android.content.Context
+import android.content.Intent
+import android.provider.Settings
+import androidx.activity.compose.BackHandler
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.background
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material.icons.automirrored.filled.Notes
+import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.CalendarMonth
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material.icons.filled.Delete
+import androidx.compose.material.icons.filled.Edit
+import androidx.compose.material.icons.filled.FileDownload
+import androidx.compose.material.icons.filled.OpenInNew
+import androidx.compose.material.icons.filled.Palette
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Button
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.TopAppBarDefaults
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.input.KeyboardCapitalization
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.ui.common.CALENDAR_COLOR_PALETTE
+import de.jeanlucmakiola.calendula.ui.common.CalendarColorChip
+import de.jeanlucmakiola.calendula.ui.common.CollapsingScaffold
+import de.jeanlucmakiola.calendula.ui.common.ColorSwatchRow
+import de.jeanlucmakiola.calendula.ui.common.GroupedRow
+import de.jeanlucmakiola.calendula.ui.common.InlineTextField
+import de.jeanlucmakiola.calendula.ui.common.Position
+import de.jeanlucmakiola.calendula.ui.common.pastelize
+import de.jeanlucmakiola.calendula.ui.common.positionOf
+import java.time.LocalDate
+
+/** Sentinel [editorId] meaning "the editor is composing a new calendar". */
+private const val NEW_CALENDAR_ID = Long.MIN_VALUE
+
+/**
+ * Calendar manager (reached from Settings). Lists the app's own device-only
+ * calendars with create / rename / recolor / delete (via a full-screen editor),
+ * and lists synced calendars read-only with a per-account "manage in the source
+ * app" deep-link — the app never touches a synced calendar's server. A
+ * full-screen destination; [onBack] pops it.
+ */
+@Composable
+fun CalendarsScreen(
+    onBack: () -> Unit,
+    viewModel: CalendarsViewModel = hiltViewModel(),
+) {
+    val calendars by viewModel.calendars.collectAsStateWithLifecycle()
+    val error by viewModel.error.collectAsStateWithLifecycle()
+    val backupResult by viewModel.backupResult.collectAsStateWithLifecycle()
+
+    // null = list; NEW_CALENDAR_ID = create; any other id = edit that calendar.
+    // [editorSession] bumps on every open so the editor's field state resets for
+    // a fresh open while still surviving configuration changes within one open.
+    var editorId by rememberSaveable { mutableStateOf<Long?>(null) }
+    var editorSession by rememberSaveable { mutableStateOf(0) }
+
+    if (editorId != null) {
+        val editing = calendars.firstOrNull { it.id == editorId }
+        CalendarEditor(
+            sessionKey = editorSession,
+            isNew = editorId == NEW_CALENDAR_ID,
+            initialName = editing?.displayName.orEmpty(),
+            initialColor = editing?.color ?: CALENDAR_COLOR_PALETTE.first(),
+            initialDescription = editing?.description.orEmpty(),
+            onSave = { name, color, description ->
+                val id = editorId
+                if (id == null || id == NEW_CALENDAR_ID) {
+                    viewModel.createCalendar(name, color, description)
+                } else {
+                    viewModel.updateCalendar(id, name, color, description)
+                }
+                editorId = null
+            },
+            onDelete = {
+                editorId?.takeIf { it != NEW_CALENDAR_ID }?.let(viewModel::deleteCalendar)
+                editorId = null
+            },
+            onClose = { editorId = null },
+        )
+    } else {
+        CalendarsList(
+            local = calendars.filter { it.isLocal },
+            synced = calendars.filterNot { it.isLocal },
+            error = error,
+            onConsumeError = viewModel::consumeError,
+            backupResult = backupResult,
+            onExportBackup = viewModel::exportBackup,
+            onConsumeBackupResult = viewModel::consumeBackupResult,
+            onBack = onBack,
+            onAdd = { editorSession++; editorId = NEW_CALENDAR_ID },
+            onEdit = { calendar -> editorSession++; editorId = calendar.id },
+        )
+    }
+}
+
+@Composable
+private fun CalendarsList(
+    local: List<CalendarSource>,
+    synced: List<CalendarSource>,
+    error: Boolean,
+    onConsumeError: () -> Unit,
+    backupResult: BackupResult?,
+    onExportBackup: (android.net.Uri) -> Unit,
+    onConsumeBackupResult: () -> Unit,
+    onBack: () -> Unit,
+    onAdd: () -> Unit,
+    onEdit: (CalendarSource) -> Unit,
+) {
+    val context = LocalContext.current
+    val snackbarHostState = remember { SnackbarHostState() }
+    val writeErrorText = stringResource(R.string.calendars_write_error)
+
+    LaunchedEffect(error) {
+        if (error) {
+            snackbarHostState.showSnackbar(writeErrorText)
+            onConsumeError()
+        }
+    }
+
+    // SAF "create document" target for the backup file. The picked Uri is handed
+    // to the VM to stream the .ics into.
+    val createBackup = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.CreateDocument("text/calendar"),
+    ) { uri -> uri?.let(onExportBackup) }
+
+    val backupFailedText = stringResource(R.string.calendars_backup_failed)
+    LaunchedEffect(backupResult) {
+        when (val r = backupResult) {
+            is BackupResult.Success -> {
+                snackbarHostState.showSnackbar(
+                    context.resources.getQuantityString(
+                        R.plurals.calendars_backup_done, r.eventCount, r.eventCount,
+                    ),
+                )
+                onConsumeBackupResult()
+            }
+            BackupResult.Failure -> {
+                snackbarHostState.showSnackbar(backupFailedText)
+                onConsumeBackupResult()
+            }
+            null -> Unit
+        }
+    }
+
+    CollapsingScaffold(
+        title = stringResource(R.string.calendars_title),
+        onBack = onBack,
+        snackbarHost = { SnackbarHost(snackbarHostState) },
+    ) {
+        // Local (device-only) calendars — the calendars the app owns. The
+        // "Add calendar" entry closes the group as its final row.
+        SectionHeader(stringResource(R.string.calendars_local_header))
+        if (local.isEmpty()) {
+            HintText(stringResource(R.string.calendars_local_empty))
+        }
+        val localCount = local.size + 1
+        local.forEachIndexed { index, calendar ->
+            GroupedRow(
+                title = calendar.displayName,
+                summary = calendar.description,
+                position = positionOf(index, localCount),
+                leading = { CalendarColorChip(calendar.color) },
+                trailing = {
+                    Icon(
+                        Icons.Default.Edit,
+                        contentDescription = stringResource(R.string.calendars_edit_title),
+                        tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                        modifier = Modifier.size(20.dp),
+                    )
+                },
+                onClick = { onEdit(calendar) },
+            )
+        }
+        GroupedRow(
+            title = stringResource(R.string.calendars_add),
+            position = positionOf(local.size, localCount),
+            leading = { AddAvatar() },
+            onClick = onAdd,
+        )
+
+        // Backup — local calendars have no sync, so a .ics export is their only
+        // safety net. Offered only when there is something to back up.
+        if (local.isNotEmpty()) {
+            Spacer(Modifier.height(16.dp))
+            SectionHeader(stringResource(R.string.calendars_backup_header))
+            HintText(stringResource(R.string.calendars_backup_hint))
+            GroupedRow(
+                title = stringResource(R.string.calendars_backup_action),
+                position = Position.Alone,
+                leading = { LeadingAvatar(Icons.Default.FileDownload) },
+                onClick = {
+                    runCatching { createBackup.launch("calendula-backup-${LocalDate.now()}.ics") }
+                },
+            )
+        }
+
+        Spacer(Modifier.height(16.dp))
+
+        // Synced calendars — read-only, grouped by account, each with a
+        // per-account "manage in source app" link.
+        SectionHeader(stringResource(R.string.calendars_synced_header))
+        HintText(stringResource(R.string.calendars_synced_hint))
+        synced
+            .groupBy { it.accountName.ifBlank { it.accountType } }
+            .forEach { (account, cals) ->
+                AccountHeader(account = account, accountType = cals.first().accountType)
+                cals.forEachIndexed { index, calendar ->
+                    GroupedRow(
+                        title = calendar.displayName,
+                        position = positionOf(index, cals.size),
+                        leading = { CalendarColorChip(calendar.color) },
+                    )
+                }
+            }
+        Spacer(Modifier.height(8.dp))
+        GroupedRow(
+            title = stringResource(R.string.calendars_add_account),
+            position = Position.Alone,
+            leading = { AddAvatar() },
+            onClick = {
+                runCatching { context.startActivity(Intent(Settings.ACTION_ADD_ACCOUNT)) }
+            },
+        )
+    }
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+private fun CalendarEditor(
+    sessionKey: Int,
+    isNew: Boolean,
+    initialName: String,
+    initialColor: Int,
+    initialDescription: String,
+    onSave: (name: String, color: Int, description: String?) -> Unit,
+    onDelete: () -> Unit,
+    onClose: () -> Unit,
+) {
+    var name by rememberSaveable(sessionKey) { mutableStateOf(initialName) }
+    var color by rememberSaveable(sessionKey) { mutableStateOf(initialColor) }
+    var description by rememberSaveable(sessionKey) { mutableStateOf(initialDescription) }
+    var confirmDelete by remember { mutableStateOf(false) }
+    val dark = isSystemInDarkTheme()
+
+    BackHandler(onBack = onClose)
+
+    Scaffold(
+        modifier = Modifier
+            .fillMaxSize()
+            .background(MaterialTheme.colorScheme.surface),
+        topBar = {
+            TopAppBar(
+                title = {
+                    Text(
+                        stringResource(
+                            if (isNew) R.string.calendars_new_title
+                            else R.string.calendars_edit_title,
+                        ),
+                    )
+                },
+                navigationIcon = {
+                    IconButton(onClick = onClose) {
+                        Icon(
+                            Icons.Default.Close,
+                            contentDescription = stringResource(R.string.event_edit_close),
+                        )
+                    }
+                },
+                actions = {
+                    if (!isNew) {
+                        IconButton(onClick = { confirmDelete = true }) {
+                            Icon(
+                                Icons.Default.Delete,
+                                contentDescription = stringResource(R.string.event_detail_delete),
+                                tint = MaterialTheme.colorScheme.error,
+                            )
+                        }
+                    }
+                    // Filled save button, matching the event editor's top bar.
+                    Button(
+                        onClick = {
+                            onSave(name.trim(), color, description.trim().ifEmpty { null })
+                        },
+                        enabled = name.isNotBlank(),
+                        modifier = Modifier.padding(end = 12.dp),
+                    ) {
+                        Text(stringResource(R.string.event_edit_save))
+                    }
+                },
+                colors = TopAppBarDefaults.topAppBarColors(
+                    containerColor = MaterialTheme.colorScheme.surface,
+                ),
+            )
+        },
+    ) { innerPadding ->
+        Column(
+            modifier = Modifier
+                .padding(innerPadding)
+                .fillMaxSize()
+                .verticalScroll(rememberScrollState())
+                .padding(horizontal = 16.dp, vertical = 8.dp),
+            verticalArrangement = Arrangement.spacedBy(12.dp),
+        ) {
+            EditorCard(icon = Icons.Default.CalendarMonth, iconTint = pastelize(color, dark)) {
+                InlineTextField(
+                    value = name,
+                    onValueChange = { name = it },
+                    placeholder = stringResource(R.string.calendars_name_label),
+                    textStyle = MaterialTheme.typography.titleLarge,
+                    capitalization = KeyboardCapitalization.Sentences,
+                )
+            }
+            EditorCard(
+                icon = Icons.Default.Palette,
+                iconTint = MaterialTheme.colorScheme.onSurfaceVariant,
+                iconAtTop = true,
+            ) {
+                Text(
+                    text = stringResource(R.string.calendars_color_label),
+                    style = MaterialTheme.typography.labelLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+                Spacer(Modifier.height(12.dp))
+                ColorSwatchRow(
+                    colors = CALENDAR_COLOR_PALETTE,
+                    selected = color,
+                    onSelect = { color = it },
+                    dark = dark,
+                )
+            }
+            EditorCard(
+                icon = Icons.AutoMirrored.Filled.Notes,
+                iconTint = MaterialTheme.colorScheme.onSurfaceVariant,
+                iconAtTop = true,
+            ) {
+                InlineTextField(
+                    value = description,
+                    onValueChange = { description = it },
+                    placeholder = stringResource(R.string.calendars_description_hint),
+                    singleLine = false,
+                    minLines = 2,
+                    capitalization = KeyboardCapitalization.Sentences,
+                )
+            }
+        }
+    }
+
+    if (confirmDelete) {
+        AlertDialog(
+            onDismissRequest = { confirmDelete = false },
+            title = { Text(stringResource(R.string.calendars_delete_confirm_title)) },
+            text = {
+                Text(stringResource(R.string.calendars_delete_confirm_message, initialName))
+            },
+            confirmButton = {
+                TextButton(onClick = {
+                    confirmDelete = false
+                    onDelete()
+                }) {
+                    Text(
+                        stringResource(R.string.event_detail_delete),
+                        color = MaterialTheme.colorScheme.error,
+                    )
+                }
+            },
+            dismissButton = {
+                TextButton(onClick = { confirmDelete = false }) {
+                    Text(stringResource(R.string.dialog_cancel))
+                }
+            },
+        )
+    }
+}
+
+/** Tonal field card matching the event editor's design (icon + content). */
+@Composable
+private fun EditorCard(
+    icon: ImageVector,
+    iconTint: Color,
+    iconAtTop: Boolean = false,
+    content: @Composable () -> Unit,
+) {
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        shape = RoundedCornerShape(16.dp),
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Row(
+            modifier = Modifier.padding(16.dp),
+            verticalAlignment = if (iconAtTop) Alignment.Top else Alignment.CenterVertically,
+        ) {
+            Icon(
+                imageVector = icon,
+                contentDescription = null,
+                tint = iconTint,
+                modifier = Modifier
+                    .padding(top = if (iconAtTop) 2.dp else 0.dp)
+                    .size(24.dp),
+            )
+            Spacer(Modifier.width(16.dp))
+            Column(modifier = Modifier.weight(1f)) { content() }
+        }
+    }
+}
+
+@Composable
+private fun AccountHeader(account: String, accountType: String) {
+    val context = LocalContext.current
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(start = 28.dp, end = 16.dp, top = 16.dp, bottom = 4.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Text(
+            text = account,
+            style = MaterialTheme.typography.titleSmall,
+            fontWeight = FontWeight.SemiBold,
+            modifier = Modifier.weight(1f),
+        )
+        OutlinedButton(onClick = {
+            runCatching { context.startActivity(sourceAppIntent(context, accountType)) }
+        }) {
+            Icon(Icons.Default.OpenInNew, contentDescription = null, modifier = Modifier.size(16.dp))
+            Spacer(Modifier.width(6.dp))
+            Text(stringResource(R.string.calendars_manage_in_app))
+        }
+    }
+}
+
+/** Neutral circular chip carrying an arbitrary icon — matches [AddAvatar]'s shape. */
+@Composable
+private fun LeadingAvatar(icon: ImageVector) {
+    Box(
+        modifier = Modifier
+            .size(40.dp)
+            .clip(CircleShape)
+            .background(MaterialTheme.colorScheme.surfaceContainerHighest),
+        contentAlignment = Alignment.Center,
+    ) {
+        Icon(
+            icon,
+            contentDescription = null,
+            tint = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.size(22.dp),
+        )
+    }
+}
+
+/** Neutral circular chip with a "+" — the leading icon for add-actions. */
+@Composable
+private fun AddAvatar() {
+    Box(
+        modifier = Modifier
+            .size(40.dp)
+            .clip(CircleShape)
+            .background(MaterialTheme.colorScheme.surfaceContainerHighest),
+        contentAlignment = Alignment.Center,
+    ) {
+        Icon(
+            Icons.Default.Add,
+            contentDescription = null,
+            tint = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.size(22.dp),
+        )
+    }
+}
+
+@Composable
+private fun SectionHeader(text: String) {
+    Text(
+        text = text,
+        style = MaterialTheme.typography.labelLarge,
+        color = MaterialTheme.colorScheme.primary,
+        modifier = Modifier.padding(start = 24.dp, end = 24.dp, top = 16.dp, bottom = 4.dp),
+    )
+}
+
+@Composable
+private fun HintText(text: String) {
+    Text(
+        text = text,
+        style = MaterialTheme.typography.bodySmall,
+        color = MaterialTheme.colorScheme.onSurfaceVariant,
+        modifier = Modifier.padding(horizontal = 24.dp, vertical = 4.dp),
+    )
+}
+
+/**
+ * Pick the app to open for managing a synced calendar's account. The account's
+ * own authenticator package (resolved from [AccountManager], no permission
+ * needed) handles any sync provider — DAVx5, ICSx5, Nextcloud, … — and a small
+ * curated map redirects the few cases where the authenticator isn't the app to
+ * open (Google's authenticator is Play Services, but users want the Calendar
+ * app). Falls back to the system account settings when nothing launchable is
+ * found, so the button always lands somewhere sensible.
+ */
+private fun sourceAppIntent(context: Context, accountType: String): Intent {
+    val pm = context.packageManager
+    val candidates = buildList {
+        AccountManager.get(context).authenticatorTypes
+            .firstOrNull { it.type.equals(accountType, ignoreCase = true) }
+            ?.packageName
+            ?.let { add(it) }
+        curatedSourcePackage(accountType)?.let { add(it) }
+    }
+    for (pkg in candidates) {
+        pm.getLaunchIntentForPackage(pkg)?.let { return it }
+    }
+    return Intent(Settings.ACTION_SYNC_SETTINGS)
+}
+
+/** Preferred app for account types whose authenticator isn't the app to open. */
+private fun curatedSourcePackage(accountType: String): String? = when {
+    accountType.equals("com.google", ignoreCase = true) -> "com.google.android.calendar"
+    else -> null
+}
+

app/src/main/java/de/jeanlucmakiola/calendula/ui/calendars/CalendarsViewModel.kt

@@ -0,0 +1,113 @@
+package de.jeanlucmakiola.calendula.ui.calendars
+
+import android.net.Uri
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.data.ics.IcsExporter
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.ics.IcsWriter
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import kotlin.coroutines.cancellation.CancellationException
+import kotlin.time.Clock
+import javax.inject.Inject
+
+/**
+ * Backs the calendar manager: lists every calendar (the screen splits them into
+ * the app's own local calendars and read-only/synced ones) and creates,
+ * renames, recolors or deletes the local calendars the app owns. Write failures
+ * flip [error] so the screen can surface a one-shot message.
+ */
+@HiltViewModel
+class CalendarsViewModel @Inject constructor(
+    private val repository: CalendarRepository,
+    private val icsExporter: IcsExporter,
+    @IoDispatcher private val io: CoroutineDispatcher,
+) : ViewModel() {
+
+    val calendars: StateFlow<List<CalendarSource>> =
+        repository.calendars()
+            .catch { emit(emptyList()) }
+            .flowOn(io)
+            .stateIn(
+                scope = viewModelScope,
+                started = SharingStarted.WhileSubscribed(5_000L),
+                initialValue = emptyList(),
+            )
+
+    private val _error = MutableStateFlow(false)
+    val error: StateFlow<Boolean> = _error.asStateFlow()
+
+    fun consumeError() { _error.value = false }
+
+    private val _backupResult = MutableStateFlow<BackupResult?>(null)
+    val backupResult: StateFlow<BackupResult?> = _backupResult.asStateFlow()
+
+    fun consumeBackupResult() { _backupResult.value = null }
+
+    /**
+     * Serialise every event of the writable local calendars into the chosen SAF
+     * document [uri] as one `VCALENDAR`. Result (event count, or failure) lands
+     * in [backupResult] for a one-shot message.
+     */
+    fun exportBackup(uri: Uri) {
+        viewModelScope.launch {
+            _backupResult.value = try {
+                val count = withContext(io) {
+                    val events = repository.exportEvents()
+                    icsExporter.writeDocument(
+                        uri = uri,
+                        content = IcsWriter().writeCalendar(events, Clock.System.now()),
+                    )
+                    events.size
+                }
+                BackupResult.Success(count)
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: Exception) {
+                BackupResult.Failure
+            }
+        }
+    }
+
+    fun createCalendar(displayName: String, color: Int, description: String?) = write {
+        repository.createLocalCalendar(displayName, color, description)
+    }
+
+    fun updateCalendar(id: Long, displayName: String, color: Int, description: String?) = write {
+        repository.updateCalendar(id, displayName, color, description)
+    }
+
+    fun deleteCalendar(id: Long) = write {
+        repository.deleteCalendar(id)
+    }
+
+    private inline fun write(crossinline block: suspend () -> Unit) {
+        viewModelScope.launch {
+            try {
+                block()
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: Exception) {
+                _error.value = true
+            }
+        }
+    }
+}
+
+/** Outcome of a whole-calendar backup, surfaced once to the screen. */
+sealed interface BackupResult {
+    data class Success(val eventCount: Int) : BackupResult
+    data object Failure : BackupResult
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarColors.kt

@@ -1,6 +1,20 @@
 package de.jeanlucmakiola.calendula.ui.common
 
+import androidx.compose.foundation.background
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.CalendarMonth
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.unit.dp
 
 /**
  * Soften a raw calendar color toward a pastel that fits the active theme.
@@ -15,3 +29,27 @@ fun pastelize(rawArgb: Int, dark: Boolean): Color {
     hsv[2] = if (dark) 0.82f else 0.72f
     return Color(android.graphics.Color.HSVToColor(hsv))
 }
+
+/**
+ * Leading avatar for a calendar: a neutral chip holding a calendar glyph tinted
+ * in the calendar's (pastelised) colour. Shared by the calendar manager and the
+ * visibility filter so they read identically.
+ */
+@Composable
+fun CalendarColorChip(color: Int, modifier: Modifier = Modifier) {
+    val dark = isSystemInDarkTheme()
+    Box(
+        modifier = modifier
+            .size(40.dp)
+            .clip(CircleShape)
+            .background(MaterialTheme.colorScheme.surfaceContainerHighest),
+        contentAlignment = Alignment.Center,
+    ) {
+        Icon(
+            Icons.Filled.CalendarMonth,
+            contentDescription = null,
+            tint = pastelize(color, dark),
+            modifier = Modifier.size(22.dp),
+        )
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarDatePickerDialog.kt

@@ -0,0 +1,52 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.material3.DatePicker
+import androidx.compose.material3.DatePickerDialog
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.rememberDatePickerState
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.res.stringResource
+import de.jeanlucmakiola.calendula.R
+import kotlinx.datetime.LocalDate
+
+/** One UTC day in milliseconds — the unit the M3 [DatePicker] speaks. */
+const val MILLIS_PER_DAY: Long = 86_400_000L
+
+/**
+ * The app's standard Material 3 date picker, opened on [initial] and reporting
+ * the chosen day through [onConfirm]. Shared by the event form (start/end date,
+ * RRULE until) and the drawer's jump-to-date action.
+ *
+ * DatePicker speaks UTC-midnight millis; epoch-day arithmetic keeps the
+ * conversion zone-proof in both directions.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun CalendarDatePickerDialog(
+    initial: LocalDate,
+    onConfirm: (LocalDate) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    val state = rememberDatePickerState(
+        initialSelectedDateMillis = initial.toEpochDays() * MILLIS_PER_DAY,
+    )
+    DatePickerDialog(
+        onDismissRequest = onDismiss,
+        confirmButton = {
+            TextButton(
+                onClick = {
+                    state.selectedDateMillis?.let { millis ->
+                        onConfirm(LocalDate.fromEpochDays((millis / MILLIS_PER_DAY).toInt()))
+                    }
+                },
+            ) { Text(stringResource(R.string.dialog_ok)) }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) { Text(stringResource(R.string.dialog_cancel)) }
+        },
+    ) {
+        DatePicker(state = state)
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarDrawer.kt

@@ -1,65 +1,165 @@
 package de.jeanlucmakiola.calendula.ui.common
 
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
-import androidx.compose.material3.HorizontalDivider
+import androidx.compose.foundation.layout.requiredSize
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.DateRange
+import androidx.compose.material.icons.filled.Settings
+import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.ModalDrawerSheet
-import androidx.compose.material3.NavigationDrawerItem
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.res.colorResource
+import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
 import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.ui.filter.CalendarFilterList
+import kotlinx.datetime.LocalDate
 
 /**
- * Navigation drawer shared by every top-level calendar screen (M2/M3/M4
- * entry points). Stateless — the host screen owns the drawer state and wires
- * the callbacks.
+ * Navigation drawer shared by every top-level calendar screen.
+ *
+ * Uses the app's grouped-card design system (see [GroupedRow]): a branded
+ * header, the View switcher as a grouped card (the active view highlighted),
+ * a jump-to-date action, the per-calendar visibility filter (M3) inline, and a
+ * pinned Settings row. The "View" section mirrors the top-bar switcher pill —
+ * tapping a view here selects it (and closes the drawer) rather than cycling.
+ * The host screen owns the drawer state.
+ *
+ * [currentDate] seeds the jump-to-date picker (the visible day/week-start/month
+ * anchor); [onJumpToDate] navigates the active view to the chosen day.
  */
 @Composable
 fun CalendarDrawer(
-    onToday: () -> Unit,
-    onJumpToDate: () -> Unit,
-    onFilter: () -> Unit,
+    currentView: CalendarView,
+    currentDate: LocalDate,
+    onSelectView: (CalendarView) -> Unit,
+    onJumpToDate: (LocalDate) -> Unit,
     onSettings: () -> Unit,
 ) {
+    var showDatePicker by remember { mutableStateOf(false) }
+
     ModalDrawerSheet {
+        // The whole sidebar scrolls as one — header, views, the calendar filter
+        // and Settings all flow in a single scroll container.
+        Column(
+            Modifier
+                .fillMaxHeight()
+                .verticalScroll(rememberScrollState()),
+        ) {
+            DrawerHeader()
+
+            DrawerSectionHeader(stringResource(R.string.view_section))
+            IMPLEMENTED_VIEWS.forEachIndexed { index, view ->
+                GroupedRow(
+                    title = stringResource(view.labelRes),
+                    position = positionOf(index, IMPLEMENTED_VIEWS.size),
+                    selected = view == currentView,
+                    minHeight = 56.dp,
+                    leading = { Icon(view.icon, contentDescription = null) },
+                    onClick = { onSelectView(view) },
+                )
+            }
+
+            Spacer(Modifier.height(16.dp))
+            GroupedRow(
+                title = stringResource(R.string.drawer_jump_to_date),
+                position = Position.Alone,
+                minHeight = 56.dp,
+                leading = { Icon(Icons.Filled.DateRange, contentDescription = null) },
+                onClick = { showDatePicker = true },
+            )
+
+            Spacer(Modifier.height(16.dp))
+
+            DrawerSectionHeader(stringResource(R.string.filter_title))
+            CalendarFilterList()
+
+            Spacer(Modifier.height(16.dp))
+            GroupedRow(
+                title = stringResource(R.string.month_action_settings),
+                position = Position.Alone,
+                minHeight = 56.dp,
+                leading = { Icon(Icons.Filled.Settings, contentDescription = null) },
+                onClick = onSettings,
+            )
+            Spacer(Modifier.height(8.dp))
+        }
+    }
+
+    if (showDatePicker) {
+        CalendarDatePickerDialog(
+            initial = currentDate,
+            onConfirm = {
+                showDatePicker = false
+                onJumpToDate(it)
+            },
+            onDismiss = { showDatePicker = false },
+        )
+    }
+}
+
+/** Branded header: the app-icon chip beside the app name. */
+@Composable
+private fun DrawerHeader() {
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(start = 28.dp, end = 28.dp, top = 24.dp, bottom = 16.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Box(
+            modifier = Modifier
+                .size(44.dp)
+                .clip(RoundedCornerShape(14.dp))
+                .background(colorResource(R.color.ic_launcher_background)),
+            contentAlignment = Alignment.Center,
+        ) {
+            Image(
+                painter = painterResource(R.drawable.ic_launcher_foreground),
+                contentDescription = null,
+                modifier = Modifier.requiredSize(66.dp),
+            )
+        }
+        Spacer(Modifier.width(16.dp))
         Text(
             text = stringResource(R.string.app_name),
             style = MaterialTheme.typography.titleLarge,
-            modifier = Modifier.padding(horizontal = 28.dp, vertical = 24.dp),
-        )
-        HorizontalDivider()
-        Spacer(Modifier.height(8.dp))
-        NavigationDrawerItem(
-            label = { Text(stringResource(R.string.month_today_action)) },
-            selected = false,
-            onClick = onToday,
-            modifier = Modifier.padding(horizontal = 12.dp),
-        )
-        NavigationDrawerItem(
-            label = { Text(stringResource(R.string.month_action_jump_to_date)) },
-            selected = false,
-            onClick = onJumpToDate,
-            modifier = Modifier.padding(horizontal = 12.dp),
-        )
-        NavigationDrawerItem(
-            label = { Text(stringResource(R.string.month_action_filter)) },
-            selected = false,
-            onClick = onFilter,
-            modifier = Modifier.padding(horizontal = 12.dp),
-        )
-        Spacer(Modifier.height(8.dp))
-        HorizontalDivider()
-        Spacer(Modifier.height(8.dp))
-        NavigationDrawerItem(
-            label = { Text(stringResource(R.string.month_action_settings)) },
-            selected = false,
-            onClick = onSettings,
-            modifier = Modifier.padding(horizontal = 12.dp),
         )
     }
 }
+
+/** Top-level grouping label in the drawer. Text only, so it never reads as a
+ *  tappable nav item. */
+@Composable
+private fun DrawerSectionHeader(text: String) {
+    Text(
+        text = text,
+        style = MaterialTheme.typography.titleSmall,
+        color = MaterialTheme.colorScheme.primary,
+        modifier = Modifier.padding(start = 28.dp, end = 28.dp, top = 16.dp, bottom = 8.dp),
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarFabColumn.kt

@@ -0,0 +1,58 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.scaleIn
+import androidx.compose.animation.scaleOut
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.Refresh
+import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
+import androidx.compose.material3.ExtendedFloatingActionButton
+import androidx.compose.material3.FloatingActionButton
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import de.jeanlucmakiola.calendula.R
+
+/**
+ * The FAB stack shared by the three calendar views: a persistent "+" to
+ * create an event, with the jump-to-today pill appearing above it whenever
+ * the view isn't anchored on today.
+ */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun CalendarFabColumn(
+    todayVisible: Boolean,
+    todayText: String,
+    onToday: () -> Unit,
+    onCreate: () -> Unit,
+) {
+    Column(
+        horizontalAlignment = Alignment.End,
+        verticalArrangement = Arrangement.spacedBy(16.dp),
+    ) {
+        AnimatedVisibility(
+            visible = todayVisible,
+            enter = scaleIn(MaterialTheme.motionScheme.fastSpatialSpec()),
+            exit = scaleOut(MaterialTheme.motionScheme.fastSpatialSpec()),
+        ) {
+            ExtendedFloatingActionButton(
+                onClick = onToday,
+                icon = { Icon(Icons.Default.Refresh, contentDescription = null) },
+                text = { Text(todayText) },
+            )
+        }
+        FloatingActionButton(onClick = onCreate) {
+            Icon(
+                imageVector = Icons.Default.Add,
+                contentDescription = stringResource(R.string.event_edit_new_title),
+            )
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/CalendarView.kt

@@ -1,13 +1,39 @@
 package de.jeanlucmakiola.calendula.ui.common
 
-/**
- * The top-level calendar views the user can switch between (spec M1).
- * Day is declared but not yet implemented (v0.5) — see [IMPLEMENTED_VIEWS].
- */
+import androidx.annotation.StringRes
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.CalendarViewDay
+import androidx.compose.material.icons.filled.CalendarViewMonth
+import androidx.compose.material.icons.filled.CalendarViewWeek
+import androidx.compose.material.icons.filled.ViewAgenda
+import androidx.compose.ui.graphics.vector.ImageVector
+import de.jeanlucmakiola.calendula.R
+
+/** The top-level calendar views the user can switch between (spec M1). */
 enum class CalendarView {
     Month,
     Week,
     Day,
+    Agenda,
+}
+
+/** Switcher label, shared by the top-bar pill and the drawer's View section. */
+@get:StringRes
+val CalendarView.labelRes: Int
+    get() = when (this) {
+        CalendarView.Month -> R.string.view_month
+        CalendarView.Week -> R.string.view_week
+        CalendarView.Day -> R.string.view_day
+        CalendarView.Agenda -> R.string.view_agenda
+    }
+
+/** Leading icon for the view in the drawer's View section. */
+val CalendarView.icon: ImageVector
+    get() = when (this) {
+        CalendarView.Month -> Icons.Filled.CalendarViewMonth
+        CalendarView.Week -> Icons.Filled.CalendarViewWeek
+        CalendarView.Day -> Icons.Filled.CalendarViewDay
+        CalendarView.Agenda -> Icons.Filled.ViewAgenda
     }
 
 /**
@@ -15,7 +41,7 @@ enum class CalendarView {
  * through these in order.
  */
 val IMPLEMENTED_VIEWS: List<CalendarView> =
-    listOf(CalendarView.Month, CalendarView.Week, CalendarView.Day)
+    listOf(CalendarView.Month, CalendarView.Week, CalendarView.Day, CalendarView.Agenda)
 
 /** Next view in [available], wrapping around. Falls back to Month if absent. */
 fun CalendarView.next(available: List<CalendarView> = IMPLEMENTED_VIEWS): CalendarView {

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/ColorSwatchRow.kt

@@ -0,0 +1,82 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.border
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.ExperimentalLayoutApi
+import androidx.compose.foundation.layout.FlowRow
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Check
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.unit.dp
+
+/**
+ * A wrapping row of round colour swatches; the one matching [selected] is
+ * ringed and checked. Shared by the calendar editor and the event-colour
+ * picker so both pick a colour the same way. Swatches render through
+ * [pastelize] — the softened colour the app actually paints, not the raw hue.
+ */
+@OptIn(ExperimentalLayoutApi::class)
+@Composable
+fun ColorSwatchRow(
+    colors: List<Int>,
+    selected: Int?,
+    onSelect: (Int) -> Unit,
+    dark: Boolean,
+    modifier: Modifier = Modifier,
+) {
+    FlowRow(modifier = modifier, horizontalArrangement = Arrangement.spacedBy(12.dp)) {
+        colors.forEach { argb ->
+            val isSelected = argb == selected
+            Box(
+                contentAlignment = Alignment.Center,
+                modifier = Modifier
+                    .padding(vertical = 4.dp)
+                    .size(40.dp)
+                    .clip(CircleShape)
+                    .background(pastelize(argb, dark))
+                    .then(
+                        if (isSelected) {
+                            Modifier.border(2.dp, MaterialTheme.colorScheme.onSurface, CircleShape)
+                        } else {
+                            Modifier
+                        },
+                    )
+                    .clickable { onSelect(argb) },
+            ) {
+                if (isSelected) {
+                    Icon(
+                        Icons.Default.Check,
+                        contentDescription = null,
+                        tint = Color.Black.copy(alpha = 0.7f),
+                        modifier = Modifier.size(20.dp),
+                    )
+                }
+            }
+        }
+    }
+}
+
+/** Google-Calendar-style palette; ARGB ints for a raw `CALENDAR_COLOR` / `EVENT_COLOR`. */
+val CALENDAR_COLOR_PALETTE: List<Int> = listOf(
+    0xFFD50000, // red
+    0xFFE67C00, // orange
+    0xFFF6BF26, // amber
+    0xFF33B679, // green
+    0xFF0B8043, // dark green
+    0xFF039BE5, // blue
+    0xFF3F51B5, // indigo
+    0xFF8E24AA, // purple
+    0xFF616161, // graphite
+).map { it.toInt() }

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/DialogControls.kt

@@ -0,0 +1,94 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.ArrowDropDown
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.unit.dp
+
+/**
+ * Tonal 3-digit number input shared by the custom reminder/recurrence steps and
+ * the reminder pickers — the app's [InlineTextField] over a tonal surface, so it
+ * matches the card/grouped-row design language (not Material's outlined field).
+ */
+@Composable
+fun DialogAmountField(
+    value: String,
+    onValueChange: (String) -> Unit,
+    placeholder: String,
+) {
+    // surfaceContainerHighest — the picker/dialog sits on surfaceContainerHigh,
+    // so anything lower vanishes.
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHighest,
+        shape = RoundedCornerShape(12.dp),
+    ) {
+        InlineTextField(
+            value = value,
+            onValueChange = { text ->
+                if (text.length <= 3 && text.all(Char::isDigit)) onValueChange(text)
+            },
+            placeholder = placeholder,
+            textStyle = MaterialTheme.typography.titleMedium,
+            keyboardType = KeyboardType.Number,
+            modifier = Modifier
+                .width(72.dp)
+                .padding(horizontal = 14.dp, vertical = 12.dp),
+        )
+    }
+}
+
+/** Tonal dropdown trigger + menu shared by the custom reminder/recurrence steps and pickers. */
+@Composable
+fun DialogUnitDropdown(
+    label: String,
+    entries: List<String>,
+    onPick: (Int) -> Unit,
+) {
+    var open by remember { mutableStateOf(false) }
+    Box {
+        Surface(
+            color = MaterialTheme.colorScheme.surfaceContainerHighest,
+            shape = RoundedCornerShape(12.dp),
+            onClick = { open = true },
+        ) {
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                modifier = Modifier.padding(start = 14.dp, end = 8.dp, top = 12.dp, bottom = 12.dp),
+            ) {
+                Text(text = label, style = MaterialTheme.typography.titleMedium)
+                Spacer(Modifier.width(4.dp))
+                Icon(imageVector = Icons.Default.ArrowDropDown, contentDescription = null)
+            }
+        }
+        DropdownMenu(expanded = open, onDismissRequest = { open = false }) {
+            entries.forEachIndexed { index, entry ->
+                DropdownMenuItem(
+                    text = { Text(entry) },
+                    onClick = {
+                        onPick(index)
+                        open = false
+                    },
+                )
+            }
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/GroupedList.kt

@@ -0,0 +1,205 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.activity.compose.BackHandler
+import androidx.compose.animation.core.animateDpAsState
+import androidx.compose.foundation.background
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.interaction.collectIsPressedAsState
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.RowScope
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.consumeWindowInsets
+import androidx.compose.foundation.layout.heightIn
+import androidx.compose.foundation.layout.imePadding
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.LargeTopAppBar
+import androidx.compose.material3.ListItem
+import androidx.compose.material3.ListItemDefaults
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TopAppBarDefaults
+import androidx.compose.material3.rememberTopAppBarState
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.input.nestedscroll.nestedScroll
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import de.jeanlucmakiola.calendula.R
+
+/**
+ * Position of a row within a grouped list, after the Android-15 settings
+ * pattern: a run of rows shares one rounded container, with full corners at the
+ * group's outer edges and small corners between, separated by small gaps.
+ */
+enum class Position { Top, Middle, Bottom, Alone }
+
+/** Maps an index within a group of [count] rows to its [Position]. */
+fun positionOf(index: Int, count: Int): Position = when {
+    count <= 1 -> Position.Alone
+    index == 0 -> Position.Top
+    index == count - 1 -> Position.Bottom
+    else -> Position.Middle
+}
+
+/**
+ * The app's standard full-screen list scaffold: a collapsing [LargeTopAppBar]
+ * whose title shrinks into the bar (next to the back button) as the content
+ * scrolls. Content is a scrollable column that feeds the toolbar via nested
+ * scroll. Used by Settings and the calendar manager so they share one shell.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun CollapsingScaffold(
+    title: String,
+    onBack: () -> Unit,
+    modifier: Modifier = Modifier,
+    snackbarHost: @Composable () -> Unit = {},
+    actions: @Composable RowScope.() -> Unit = {},
+    content: @Composable ColumnScope.() -> Unit,
+) {
+    BackHandler(onBack = onBack)
+    val scrollBehavior =
+        TopAppBarDefaults.exitUntilCollapsedScrollBehavior(rememberTopAppBarState())
+    Scaffold(
+        modifier = modifier
+            .fillMaxSize()
+            .background(MaterialTheme.colorScheme.surface)
+            .nestedScroll(scrollBehavior.nestedScrollConnection),
+        topBar = {
+            LargeTopAppBar(
+                title = { Text(title) },
+                navigationIcon = {
+                    IconButton(onClick = onBack) {
+                        Icon(
+                            Icons.AutoMirrored.Filled.ArrowBack,
+                            contentDescription = stringResource(R.string.settings_back),
+                        )
+                    }
+                },
+                actions = actions,
+                scrollBehavior = scrollBehavior,
+                colors = TopAppBarDefaults.topAppBarColors(
+                    scrolledContainerColor = MaterialTheme.colorScheme.surface,
+                ),
+            )
+        },
+        snackbarHost = snackbarHost,
+    ) { innerPadding ->
+        Column(
+            modifier = Modifier
+                .padding(innerPadding)
+                // Mark the scaffold's system-bar insets as consumed so the
+                // imePadding below adds only the keyboard height beyond them
+                // (max, not sum) — otherwise the nav-bar inset double-counts and
+                // leaves an empty strip above the keyboard.
+                .consumeWindowInsets(innerPadding)
+                .fillMaxSize()
+                // Paint the surface across the full area before imePadding carves
+                // into it, so any sliver above the keyboard reads as surface — not
+                // the dialog window's black — during the IME animation.
+                .background(MaterialTheme.colorScheme.surface)
+                // Shrink the scroll viewport by the keyboard inset so a focused
+                // field (e.g. the custom-reminder amount) can scroll into view.
+                .imePadding()
+                .verticalScroll(rememberScrollState())
+                .padding(top = 8.dp, bottom = 24.dp),
+            content = content,
+        )
+    }
+}
+
+/**
+ * One row in a grouped list: an M3 [ListItem] over a tonal [Surface] whose
+ * corner radii come from its [position] (so a run of rows reads as a single
+ * rounded card). Corners round further on press. A null [onClick] makes the
+ * row non-interactive (e.g. read-only entries).
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun GroupedRow(
+    title: String,
+    position: Position,
+    modifier: Modifier = Modifier,
+    summary: String? = null,
+    selected: Boolean = false,
+    minHeight: Dp = 72.dp,
+    leading: @Composable (() -> Unit)? = null,
+    trailing: @Composable (() -> Unit)? = null,
+    onClick: (() -> Unit)? = null,
+) {
+    val interaction = remember { MutableInteractionSource() }
+    val pressed by interaction.collectIsPressedAsState()
+    val full by animateDpAsState(if (pressed) 36.dp else 22.dp, label = "fullCorner")
+    val small by animateDpAsState(if (pressed) 36.dp else 6.dp, label = "smallCorner")
+    val shape = when (position) {
+        Position.Alone -> RoundedCornerShape(full)
+        Position.Top -> RoundedCornerShape(
+            topStart = full, topEnd = full, bottomStart = small, bottomEnd = small,
+        )
+        Position.Middle -> RoundedCornerShape(small)
+        Position.Bottom -> RoundedCornerShape(
+            topStart = small, topEnd = small, bottomStart = full, bottomEnd = full,
+        )
+    }
+    val gap = when (position) {
+        Position.Top, Position.Middle -> Modifier.padding(bottom = 2.dp)
+        Position.Bottom, Position.Alone -> Modifier
+    }
+    val itemColors = if (selected) {
+        ListItemDefaults.colors(
+            containerColor = Color.Transparent,
+            headlineColor = MaterialTheme.colorScheme.onSecondaryContainer,
+            leadingIconColor = MaterialTheme.colorScheme.onSecondaryContainer,
+            supportingColor = MaterialTheme.colorScheme.onSecondaryContainer,
+            trailingIconColor = MaterialTheme.colorScheme.onSecondaryContainer,
+        )
+    } else {
+        ListItemDefaults.colors(containerColor = Color.Transparent)
+    }
+    val item: @Composable () -> Unit = {
+        ListItem(
+            headlineContent = { Text(title) },
+            supportingContent = summary?.let { text -> { Text(text) } },
+            leadingContent = leading,
+            trailingContent = trailing,
+            colors = itemColors,
+            modifier = Modifier.heightIn(min = minHeight),
+        )
+    }
+    val base = modifier
+        .fillMaxWidth()
+        .padding(horizontal = 16.dp)
+        .then(gap)
+    val containerColor = if (selected) {
+        MaterialTheme.colorScheme.secondaryContainer
+    } else {
+        MaterialTheme.colorScheme.surfaceContainerHigh
+    }
+    if (onClick != null) {
+        Surface(
+            onClick = onClick,
+            color = containerColor,
+            shape = shape,
+            interactionSource = interaction,
+            modifier = base,
+        ) { item() }
+    } else {
+        Surface(color = containerColor, shape = shape, modifier = base) { item() }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/InlineTextField.kt

@@ -0,0 +1,74 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.text.BasicTextField
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.SolidColor
+import androidx.compose.ui.graphics.isSpecified
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.input.KeyboardCapitalization
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.unit.dp
+
+/**
+ * The app's borderless text input: no underline, no outline, just the tonal
+ * card behind it. This is the standard input across the app — we deliberately
+ * don't use Material's outlined/filled text fields, so anything that takes text
+ * (the event form, the calendar manager, dialogs) uses this inside a tonal
+ * [androidx.compose.material3.Surface].
+ */
+@Composable
+fun InlineTextField(
+    value: String,
+    onValueChange: (String) -> Unit,
+    placeholder: String,
+    modifier: Modifier = Modifier
+        .fillMaxWidth()
+        .padding(vertical = 4.dp),
+    textStyle: TextStyle = MaterialTheme.typography.titleMedium,
+    singleLine: Boolean = true,
+    minLines: Int = 1,
+    keyboardType: KeyboardType = KeyboardType.Text,
+    capitalization: KeyboardCapitalization = KeyboardCapitalization.None,
+) {
+    val resolvedStyle = textStyle.copy(
+        color = if (textStyle.color.isSpecified) {
+            textStyle.color
+        } else {
+            MaterialTheme.colorScheme.onSurface
+        },
+    )
+    BasicTextField(
+        value = value,
+        onValueChange = onValueChange,
+        textStyle = resolvedStyle,
+        singleLine = singleLine,
+        minLines = minLines,
+        keyboardOptions = KeyboardOptions(
+            keyboardType = keyboardType,
+            capitalization = capitalization,
+        ),
+        cursorBrush = SolidColor(MaterialTheme.colorScheme.primary),
+        decorationBox = { innerTextField ->
+            Box {
+                if (value.isEmpty()) {
+                    // Clearly fainter than typed text, so a hint never reads as
+                    // prefilled content.
+                    Text(
+                        text = placeholder,
+                        style = resolvedStyle,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.5f),
+                    )
+                }
+                innerTextField()
+            }
+        },
+        modifier = modifier,
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/OptionCard.kt

@@ -0,0 +1,94 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.isSpecified
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.unit.dp
+
+/**
+ * The app's standard pick in a selection dialog: a full-width tonal card,
+ * optionally with a leading icon and a supporting line; the selected option
+ * is highlighted. Stack with 8dp gaps inside an AlertDialog — this is the
+ * only sanctioned selection-modal style (no radio rows, no bare text lists).
+ */
+@Composable
+fun OptionCard(
+    label: String,
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+    icon: ImageVector? = null,
+    /** Icon tint override, e.g. a calendar colour; unspecified follows selection. */
+    iconTint: Color = Color.Unspecified,
+    supportingText: String? = null,
+    selected: Boolean = false,
+    /** Label colour override, e.g. primary for an emphasised "Custom" entry. */
+    labelColor: Color = Color.Unspecified,
+) {
+    val contentColor = if (selected) {
+        MaterialTheme.colorScheme.onSecondaryContainer
+    } else {
+        MaterialTheme.colorScheme.onSurface
+    }
+    Surface(
+        onClick = onClick,
+        color = if (selected) {
+            MaterialTheme.colorScheme.secondaryContainer
+        } else {
+            MaterialTheme.colorScheme.surfaceContainerHighest
+        },
+        shape = RoundedCornerShape(12.dp),
+        modifier = modifier.fillMaxWidth(),
+    ) {
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 14.dp),
+        ) {
+            if (icon != null) {
+                Icon(
+                    imageVector = icon,
+                    contentDescription = null,
+                    tint = when {
+                        iconTint.isSpecified -> iconTint
+                        selected -> MaterialTheme.colorScheme.onSecondaryContainer
+                        else -> MaterialTheme.colorScheme.onSurfaceVariant
+                    },
+                    modifier = Modifier.size(20.dp),
+                )
+                Spacer(Modifier.width(12.dp))
+            }
+            Column {
+                Text(
+                    text = label,
+                    style = MaterialTheme.typography.titleMedium,
+                    color = if (labelColor.isSpecified) labelColor else contentColor,
+                )
+                if (supportingText != null) {
+                    Text(
+                        text = supportingText,
+                        style = MaterialTheme.typography.bodySmall,
+                        color = if (selected) {
+                            MaterialTheme.colorScheme.onSecondaryContainer.copy(alpha = 0.8f)
+                        } else {
+                            MaterialTheme.colorScheme.onSurfaceVariant
+                        },
+                    )
+                }
+            }
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/Picker.kt

@@ -0,0 +1,282 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Check
+import androidx.compose.material3.FilledTonalButton
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.SegmentedButton
+import androidx.compose.material3.SegmentedButtonDefaults
+import androidx.compose.material3.SingleChoiceSegmentedButtonRow
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import android.view.WindowManager
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.SideEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalView
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.window.Dialog
+import androidx.compose.ui.window.DialogProperties
+import androidx.compose.ui.window.DialogWindowProvider
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.data.prefs.CalendarReminderOverride
+
+/**
+ * Shared full-screen scaffold for selection pickers: a full-bleed [Dialog] that
+ * reuses the app's [CollapsingScaffold] (collapsing title + back button), so a
+ * picker is visually identical to a Settings sub-page and uses the full width.
+ * [content] places the connected grouped rows; selecting one calls [onDismiss].
+ */
+@Composable
+fun FullScreenPicker(
+    title: String,
+    onDismiss: () -> Unit,
+    content: @Composable ColumnScope.() -> Unit,
+) {
+    Dialog(
+        onDismissRequest = onDismiss,
+        properties = DialogProperties(
+            usePlatformDefaultWidth = false,
+            decorFitsSystemWindows = false,
+        ),
+    ) {
+        // The dialog window pans by default when the keyboard opens, which —
+        // combined with the content's own imePadding — leaves a fixed black gap
+        // above the keyboard. Switch it to ADJUST_NOTHING so the window stays
+        // full-screen and imePadding alone lifts the focused field.
+        val view = LocalView.current
+        SideEffect {
+            (view.parent as? DialogWindowProvider)?.window
+                ?.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_NOTHING)
+        }
+        CollapsingScaffold(title = title, onBack = onDismiss, content = content)
+    }
+}
+
+/**
+ * General single-select picker, full-screen: each option is a connected grouped
+ * row and the current one carries a check. Drop-in for the former dialog
+ * (theme, week start, language, …).
+ */
+@Composable
+fun <T> OptionPicker(
+    title: String,
+    options: List<T>,
+    selected: T,
+    label: @Composable (T) -> String,
+    onSelect: (T) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    FullScreenPicker(title = title, onDismiss = onDismiss) {
+        options.forEachIndexed { index, option ->
+            val isSelected = option == selected
+            GroupedRow(
+                title = label(option),
+                position = positionOf(index, options.size),
+                selected = isSelected,
+                trailing = if (isSelected) {
+                    { SelectedCheck() }
+                } else {
+                    null
+                },
+                onClick = {
+                    onSelect(option)
+                    onDismiss()
+                },
+            )
+        }
+    }
+}
+
+/**
+ * Reminder-default picker, full-screen: the grouped list (with an optional "Use
+ * default reminder" row and a "None" row), the [presets] as lead-time rows, and
+ * a "Custom" row that expands an inline number field plus a segmented unit
+ * selector. Returns the choice as a [CalendarReminderOverride].
+ */
+@Composable
+fun ReminderDefaultPicker(
+    title: String,
+    presets: List<Int>,
+    selected: CalendarReminderOverride,
+    allowInherit: Boolean,
+    onSelect: (CalendarReminderOverride) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    val selectedMinutes = (selected as? CalendarReminderOverride.Minutes)?.minutes
+    val customSelected = selectedMinutes != null && selectedMinutes !in presets
+    val seed = decomposeReminder(selectedMinutes?.takeIf { customSelected })
+
+    var customExpanded by rememberSaveable { mutableStateOf(false) }
+    var amountText by rememberSaveable { mutableStateOf(seed.first) }
+    var unit by rememberSaveable { mutableStateOf(seed.second) }
+
+    val options = buildList {
+        if (allowInherit) add(CalendarReminderOverride.Inherit)
+        add(CalendarReminderOverride.None)
+        presets.forEach { add(CalendarReminderOverride.Minutes(it)) }
+    }
+    val rowCount = options.size + 1 // + the custom row
+
+    FullScreenPicker(title = title, onDismiss = onDismiss) {
+        options.forEachIndexed { index, option ->
+            val isSelected = option == selected
+            GroupedRow(
+                title = reminderOverrideLabel(option),
+                position = positionOf(index, rowCount),
+                selected = isSelected,
+                trailing = if (isSelected) {
+                    { SelectedCheck() }
+                } else {
+                    null
+                },
+                onClick = {
+                    onSelect(option)
+                    onDismiss()
+                },
+            )
+        }
+        // When expanded, the Custom row connects downward into the editor card
+        // so the two read as one grouped container (the per-calendar pattern).
+        GroupedRow(
+            title = if (customSelected) {
+                stringResource(
+                    R.string.reminder_custom_with_value,
+                    reminderLeadTimeLabel(selectedMinutes!!),
+                )
+            } else {
+                stringResource(R.string.event_edit_reminder_custom)
+            },
+            position = if (customExpanded) Position.Top else positionOf(options.size, rowCount),
+            selected = customSelected,
+            trailing = if (customSelected) {
+                { SelectedCheck() }
+            } else {
+                null
+            },
+            onClick = { customExpanded = !customExpanded },
+        )
+        AnimatedVisibility(visible = customExpanded) {
+            CustomReminderEditor(
+                amountText = amountText,
+                onAmountChange = { amountText = it },
+                unit = unit,
+                onUnitChange = { unit = it },
+                onConfirm = { minutes ->
+                    onSelect(CalendarReminderOverride.Minutes(minutes))
+                    onDismiss()
+                },
+            )
+        }
+    }
+}
+
+/**
+ * The expanded "Custom" lead-time editor: a tonal card connected to the Custom
+ * row above it (matching the grouped-row system, so the two read as one
+ * container). An amount field with a live preview of the resulting lead time, a
+ * single-choice unit toggle, and a tonal confirm enabled only for a valid
+ * 1–999 amount. [onConfirm] receives the final lead time in minutes.
+ */
+@Composable
+private fun CustomReminderEditor(
+    amountText: String,
+    onAmountChange: (String) -> Unit,
+    unit: ReminderUnit,
+    onUnitChange: (ReminderUnit) -> Unit,
+    onConfirm: (Int) -> Unit,
+) {
+    val amount = amountText.toIntOrNull()?.takeIf { it in 1..999 }
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        // A Position.Bottom shape: tight top corners meeting the row, full bottom.
+        shape = RoundedCornerShape(topStart = 6.dp, topEnd = 6.dp, bottomStart = 22.dp, bottomEnd = 22.dp),
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(horizontal = 16.dp),
+    ) {
+        Column(
+            modifier = Modifier.padding(16.dp),
+            verticalArrangement = Arrangement.spacedBy(16.dp),
+        ) {
+            // Unit toggle first so it stays visible above the keyboard once the
+            // amount field (the bottom row) is focused and scrolled into view.
+            SingleChoiceSegmentedButtonRow(modifier = Modifier.fillMaxWidth()) {
+                ReminderUnit.entries.forEachIndexed { index, entry ->
+                    SegmentedButton(
+                        selected = unit == entry,
+                        onClick = { onUnitChange(entry) },
+                        shape = SegmentedButtonDefaults.itemShape(index, ReminderUnit.entries.size),
+                        label = { Text(stringResource(reminderUnitLabel(entry))) },
+                    )
+                }
+            }
+            // Amount, a live preview of the lead time it resolves to, and Set —
+            // all on one row, sitting just above the keyboard.
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                DialogAmountField(
+                    value = amountText,
+                    onValueChange = onAmountChange,
+                    placeholder = "10",
+                )
+                Spacer(Modifier.width(16.dp))
+                Text(
+                    text = amount?.let { reminderLeadTimeLabel(it * unit.minutesFactor) }
+                        ?: stringResource(R.string.reminder_custom_amount),
+                    style = MaterialTheme.typography.bodyLarge,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    modifier = Modifier.weight(1f),
+                )
+                Spacer(Modifier.width(16.dp))
+                FilledTonalButton(
+                    onClick = { amount?.let { onConfirm(it * unit.minutesFactor) } },
+                    enabled = amount != null,
+                ) {
+                    Text(stringResource(R.string.reminder_custom_set))
+                }
+            }
+        }
+    }
+}
+
+@Composable
+private fun SelectedCheck() {
+    Icon(
+        imageVector = Icons.Default.Check,
+        contentDescription = null,
+        tint = MaterialTheme.colorScheme.primary,
+    )
+}
+
+@Composable
+private fun reminderOverrideLabel(override: CalendarReminderOverride): String = when (override) {
+    CalendarReminderOverride.Inherit -> stringResource(R.string.reminder_use_default)
+    CalendarReminderOverride.None -> stringResource(R.string.reminder_none)
+    is CalendarReminderOverride.Minutes -> reminderLeadTimeLabel(override.minutes)
+}
+
+/** Seed the custom editor: the largest exact unit for [minutes] (null → empty). */
+private fun decomposeReminder(minutes: Int?): Pair<String, ReminderUnit> = when {
+    minutes == null -> "" to ReminderUnit.Minutes
+    minutes % 10_080 == 0 -> (minutes / 10_080).toString() to ReminderUnit.Weeks
+    minutes % 1_440 == 0 -> (minutes / 1_440).toString() to ReminderUnit.Days
+    minutes % 60 == 0 -> (minutes / 60).toString() to ReminderUnit.Hours
+    else -> minutes.toString() to ReminderUnit.Minutes
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/RecurrenceText.kt

@@ -0,0 +1,126 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import android.icu.text.ListFormatter
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.SpanStyle
+import androidx.compose.ui.text.buildAnnotatedString
+import androidx.compose.ui.text.font.FontStyle
+import de.jeanlucmakiola.calendula.R
+import java.time.DayOfWeek
+import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
+import java.time.format.TextStyle as JavaTextStyle
+import java.util.Locale
+
+/**
+ * Humanise an RFC 5545 RRULE into a localized phrase, e.g.
+ * "Every week on Tue and Thu until 31 Dec 2026" or "Every day, 10 times".
+ * Falls back to a generic label for rules we don't render in full (ordinal
+ * monthly/yearly BYDAY, etc.). Shared by the detail screen and the edit
+ * form's repeat card.
+ */
+@Composable
+fun recurrenceText(rrule: String, locale: Locale): AnnotatedString {
+    val parts = rrule.removePrefix("RRULE:").split(';').mapNotNull { token ->
+        val eq = token.indexOf('=')
+        if (eq <= 0) null else token.substring(0, eq).uppercase() to token.substring(eq + 1)
+    }.toMap()
+
+    val freq = parts["FREQ"]?.uppercase()
+    val interval = parts["INTERVAL"]?.toIntOrNull() ?: 1
+    val base = when (freq) {
+        "DAILY" -> if (interval == 1) stringResource(R.string.recurrence_daily)
+        else stringResource(R.string.recurrence_every_n_days, interval)
+        "WEEKLY" -> if (interval == 1) stringResource(R.string.recurrence_weekly)
+        else stringResource(R.string.recurrence_every_n_weeks, interval)
+        "MONTHLY" -> if (interval == 1) stringResource(R.string.recurrence_monthly)
+        else stringResource(R.string.recurrence_every_n_months, interval)
+        "YEARLY" -> if (interval == 1) stringResource(R.string.recurrence_yearly)
+        else stringResource(R.string.recurrence_every_n_years, interval)
+        else -> return AnnotatedString(stringResource(R.string.event_detail_recurring))
+    }
+
+    // Weekly + BYDAY → "<base> on <days>"; other BYDAY forms keep just the base.
+    // The day names + their joined block are tracked so only the names (not the
+    // commas/conjunction) can be italicised in the final string.
+    val byDay = parts["BYDAY"]
+    var dayNames: List<String>? = null
+    var joinedDays: String? = null
+    val main = if (freq == "WEEKLY" && !byDay.isNullOrBlank()) {
+        val days = byDay.split(',').mapNotNull { rruleDayName(it.trim(), locale) }
+        if (days.isNotEmpty()) {
+            val joined = ListFormatter.getInstance(locale).format(days)
+            dayNames = days
+            joinedDays = joined
+            stringResource(R.string.recurrence_on_days, base, joined)
+        } else {
+            base
+        }
+    } else {
+        base
+    }
+
+    // End bound: UNTIL (a date) takes precedence over COUNT (a number of times).
+    val until = parts["UNTIL"]?.let { parseUntilDate(it, locale) }
+    val count = parts["COUNT"]?.toIntOrNull()
+    val full = when {
+        until != null -> stringResource(R.string.recurrence_with_until, main, until)
+        count != null -> stringResource(R.string.recurrence_with_count, main, count)
+        else -> main
+    }
+
+    return buildAnnotatedString {
+        append(full)
+        val names = dayNames
+        val joined = joinedDays
+        if (names != null && joined != null) {
+            // Italicise each day name within the joined block only — leaving the
+            // separators and conjunction ("und"/"and") in the regular style.
+            val regionStart = full.indexOf(joined)
+            if (regionStart >= 0) {
+                val regionEnd = regionStart + joined.length
+                var cursor = regionStart
+                for (name in names) {
+                    val at = full.indexOf(name, cursor)
+                    if (at in regionStart until regionEnd) {
+                        addStyle(SpanStyle(fontStyle = FontStyle.Italic), at, at + name.length)
+                        cursor = at + name.length
+                    }
+                }
+            }
+        }
+    }
+}
+
+/** Map an RRULE BYDAY token (e.g. "TU" or "2TH") to a localized short weekday name. */
+private fun rruleDayName(token: String, locale: Locale): String? {
+    val dow = when (token.takeLast(2).uppercase()) {
+        "MO" -> DayOfWeek.MONDAY
+        "TU" -> DayOfWeek.TUESDAY
+        "WE" -> DayOfWeek.WEDNESDAY
+        "TH" -> DayOfWeek.THURSDAY
+        "FR" -> DayOfWeek.FRIDAY
+        "SA" -> DayOfWeek.SATURDAY
+        "SU" -> DayOfWeek.SUNDAY
+        else -> return null
+    }
+    return dow.getDisplayName(JavaTextStyle.SHORT, locale)
+}
+
+/** Parse an RRULE UNTIL value ("20261231" or "20261231T235959Z") to a localized date. */
+private fun parseUntilDate(raw: String, locale: Locale): String? {
+    val digits = raw.takeWhile { it.isDigit() }
+    if (digits.length < 8) return null
+    return try {
+        val date = java.time.LocalDate.of(
+            digits.substring(0, 4).toInt(),
+            digits.substring(4, 6).toInt(),
+            digits.substring(6, 8).toInt(),
+        )
+        DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).withLocale(locale).format(date)
+    } catch (e: Exception) {
+        null
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/ReminderFormatting.kt

@@ -0,0 +1,46 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.annotation.StringRes
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.res.pluralStringResource
+import androidx.compose.ui.res.stringResource
+import de.jeanlucmakiola.calendula.R
+
+/** Common reminder lead times offered as quick picks in the form and settings. */
+val REMINDER_PRESETS = listOf(0, 10, 30, 60, 1_440)
+
+/** The unit of a custom reminder lead time; [minutesFactor] converts to minutes. */
+enum class ReminderUnit(val minutesFactor: Int) {
+    Minutes(1),
+    Hours(60),
+    Days(1_440),
+    Weeks(10_080),
+}
+
+@StringRes
+fun reminderUnitLabel(unit: ReminderUnit): Int = when (unit) {
+    ReminderUnit.Minutes -> R.string.reminder_unit_minutes
+    ReminderUnit.Hours -> R.string.reminder_unit_hours
+    ReminderUnit.Days -> R.string.reminder_unit_days
+    ReminderUnit.Weeks -> R.string.reminder_unit_weeks
+}
+
+/**
+ * Humanise a reminder lead time (minutes before the event start) into one
+ * line: "Default reminder" (negative = the provider default), "At time of
+ * event" (0), "10 minutes before", "1 hour before", … Shared by the detail
+ * screen, the event form and the default-reminder settings so the wording
+ * never drifts.
+ */
+@Composable
+fun reminderLeadTimeLabel(minutes: Int): String = when {
+    minutes < 0 -> stringResource(R.string.reminder_default)
+    minutes == 0 -> stringResource(R.string.reminder_at_time)
+    minutes % 10_080 == 0 ->
+        pluralStringResource(R.plurals.reminder_weeks, minutes / 10_080, minutes / 10_080)
+    minutes % 1_440 == 0 ->
+        pluralStringResource(R.plurals.reminder_days, minutes / 1_440, minutes / 1_440)
+    minutes % 60 == 0 ->
+        pluralStringResource(R.plurals.reminder_hours, minutes / 60, minutes / 60)
+    else -> pluralStringResource(R.plurals.reminder_minutes, minutes, minutes)
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/TimePickerAlert.kt

@@ -0,0 +1,68 @@
+package de.jeanlucmakiola.calendula.ui.common
+
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import android.content.Context
+import android.content.res.Resources
+import android.provider.Settings
+import android.text.format.DateFormat
+import androidx.compose.material3.TimePicker
+import androidx.compose.material3.rememberTimePickerState
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.stringResource
+import de.jeanlucmakiola.calendula.R
+import kotlinx.datetime.LocalTime
+
+/**
+ * M3 time picker in an alert dialog, seeded with [initial]. Shared by the event
+ * form (start/end times) and Settings (the all-day reminder fire time).
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun TimePickerAlert(
+    initial: LocalTime,
+    onConfirm: (LocalTime) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    val state = rememberTimePickerState(
+        initialHour = initial.hour,
+        initialMinute = initial.minute,
+        is24Hour = deviceUses24HourClock(LocalContext.current),
+    )
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        confirmButton = {
+            TextButton(onClick = { onConfirm(LocalTime(state.hour, state.minute)) }) {
+                Text(stringResource(R.string.dialog_ok))
+            }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) { Text(stringResource(R.string.dialog_cancel)) }
+        },
+        text = { TimePicker(state = state) },
+    )
+}
+
+/**
+ * Whether the clock should read 24-hour, matching the rest of the device.
+ *
+ * [DateFormat.is24HourFormat] resolves a "locale default" system setting against
+ * the *app's* context locale — and this app applies a per-app language
+ * (AppCompatDelegate), so an English UI on a German-region phone would wrongly
+ * read 12-hour while the system clock shows 24-hour. So we honour an explicit
+ * system 12/24 override, and otherwise fall back to the **device** locale
+ * (Resources.getSystem), not the app's.
+ */
+private fun deviceUses24HourClock(context: Context): Boolean =
+    when (Settings.System.getString(context.contentResolver, Settings.System.TIME_12_24)) {
+        "24" -> true
+        "12" -> false
+        // 'a' is the AM/PM marker; a best-fit pattern without it is 24-hour.
+        else -> {
+            val deviceLocale = Resources.getSystem().configuration.locales[0]
+            !DateFormat.getBestDateTimePattern(deviceLocale, "jm").contains('a')
+        }
+    }

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/ViewSwitcherPill.kt

@@ -6,7 +6,6 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.stringResource
-import de.jeanlucmakiola.calendula.R
 
 /**
  * Top-bar pill that shows the current view and cycles to the next one on tap
@@ -18,16 +17,11 @@ fun ViewSwitcherPill(
     onCycle: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
-    val labelRes = when (current) {
-        CalendarView.Month -> R.string.view_month
-        CalendarView.Week -> R.string.view_week
-        CalendarView.Day -> R.string.view_day
-    }
     FilledTonalButton(
         onClick = onCycle,
         shape = MaterialTheme.shapes.large,
         modifier = modifier,
     ) {
-        Text(stringResource(labelRes))
+        Text(stringResource(current.labelRes))
     }
 }

app/src/main/java/de/jeanlucmakiola/calendula/ui/day/DayScreen.kt

@@ -1,13 +1,12 @@
 package de.jeanlucmakiola.calendula.ui.day
 
 import androidx.compose.animation.AnimatedContent
-import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.animateColorAsState
 import androidx.compose.animation.core.animateDpAsState
-import androidx.compose.animation.scaleIn
-import androidx.compose.animation.scaleOut
 import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.gestures.detectHorizontalDragGestures
+import androidx.compose.foundation.gestures.detectTapGestures
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.BoxWithConstraints
@@ -27,12 +26,10 @@ import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Menu
-import androidx.compose.material.icons.filled.Refresh
 import androidx.compose.material3.Card
 import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.DrawerValue
 import androidx.compose.material3.ExperimentalMaterial3Api
-import androidx.compose.material3.ExtendedFloatingActionButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
@@ -71,6 +68,7 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.calendula.R
 import de.jeanlucmakiola.calendula.domain.EventInstance
 import de.jeanlucmakiola.calendula.ui.common.CalendarDrawer
+import de.jeanlucmakiola.calendula.ui.common.CalendarFabColumn
 import de.jeanlucmakiola.calendula.ui.common.CalendarFailure
 import de.jeanlucmakiola.calendula.ui.common.CalendarView
 import de.jeanlucmakiola.calendula.ui.common.ViewSwitcherPill
@@ -105,12 +103,21 @@ private fun DayUiState.Success.allDayStripHeight(): Dp {
 fun DayScreen(
     selectedView: CalendarView,
     onSelectView: (CalendarView) -> Unit,
+    onEventClick: (EventInstance) -> Unit,
+    onOpenSettings: () -> Unit,
+    onCreateEvent: (LocalDate, Int?) -> Unit,
     modifier: Modifier = Modifier,
+    initialDateIso: String? = null,
     viewModel: DayViewModel = hiltViewModel(),
 ) {
     val state by viewModel.state.collectAsStateWithLifecycle()
     val date by viewModel.date.collectAsStateWithLifecycle()
 
+    // When opened from the month grid, anchor to the tapped date.
+    LaunchedEffect(initialDateIso) {
+        initialDateIso?.let { viewModel.goToDate(LocalDate.parse(it)) }
+    }
+
     val scrollBehavior = TopAppBarDefaults.pinnedScrollBehavior()
     val drawerState = rememberDrawerState(DrawerValue.Closed)
     val scope = rememberCoroutineScope()
@@ -135,7 +142,20 @@ fun DayScreen(
     var slideDir by remember { mutableIntStateOf(0) }
     val goNext = { slideDir = 1; viewModel.goToNext() }
     val goPrev = { slideDir = -1; viewModel.goToPrev() }
-    val jumpToToday = { slideDir = 0; viewModel.goToToday() }
+    // Slide toward today: viewing the future → today comes in from the left
+    // (back), viewing the past → from the right (forward).
+    val jumpToToday = {
+        slideDir = when (val s = state) {
+            is DayUiState.Success -> if (s.today < s.date) -1 else 1
+            else -> 0
+        }
+        viewModel.goToToday()
+    }
+    // Drawer jump-to-date: slide from the side the target lies on.
+    val jumpToDate: (LocalDate) -> Unit = { target ->
+        slideDir = if (target < date) -1 else 1
+        viewModel.goToDate(target)
+    }
 
     ModalNavigationDrawer(
         drawerState = drawerState,
@@ -143,10 +163,20 @@ fun DayScreen(
         gesturesEnabled = drawerState.isOpen,
         drawerContent = {
             CalendarDrawer(
-                onToday = { jumpToToday(); scope.launch { drawerState.close() } },
-                onJumpToDate = { scope.launch { drawerState.close() } /* TODO: date picker */ },
-                onFilter = { scope.launch { drawerState.close() } /* TODO: filter sheet */ },
-                onSettings = { scope.launch { drawerState.close() } /* TODO: settings */ },
+                currentView = selectedView,
+                currentDate = date,
+                onSelectView = { view ->
+                    onSelectView(view)
+                    scope.launch { drawerState.close() }
+                },
+                onJumpToDate = { target ->
+                    jumpToDate(target)
+                    scope.launch { drawerState.close() }
+                },
+                onSettings = {
+                    onOpenSettings()
+                    scope.launch { drawerState.close() }
+                },
             )
         },
     ) {
@@ -162,17 +192,12 @@ fun DayScreen(
                 )
             },
             floatingActionButton = {
-                AnimatedVisibility(
-                    visible = !isOnToday,
-                    enter = scaleIn(),
-                    exit = scaleOut(),
-                ) {
-                    ExtendedFloatingActionButton(
-                        onClick = jumpToToday,
-                        icon = { Icon(Icons.Default.Refresh, contentDescription = null) },
-                        text = { Text(stringResource(R.string.day_today_action)) },
+                CalendarFabColumn(
+                    todayVisible = !isOnToday,
+                    todayText = stringResource(R.string.day_today_action),
+                    onToday = jumpToToday,
+                    onCreate = { onCreateEvent(date, null) },
                 )
-                }
             },
         ) { innerPadding ->
             DayContent(
@@ -182,6 +207,8 @@ fun DayScreen(
                 onSwipeNext = goNext,
                 onSwipePrev = goPrev,
                 onRetry = jumpToToday,
+                onEventClick = onEventClick,
+                onCreateAt = { d, minutes -> onCreateEvent(d, minutes) },
                 modifier = Modifier
                     .padding(innerPadding)
                     .fillMaxSize(),
@@ -198,6 +225,8 @@ private fun DayContent(
     onSwipeNext: () -> Unit,
     onSwipePrev: () -> Unit,
     onRetry: () -> Unit,
+    onEventClick: (EventInstance) -> Unit,
+    onCreateAt: (LocalDate, Int) -> Unit,
     modifier: Modifier = Modifier,
 ) {
     val density = LocalDensity.current
@@ -265,6 +294,8 @@ private fun DayContent(
                 topSectionColor = topSectionColor,
                 scrollState = scrollState,
                 allDayHeight = allDayHeight,
+                onEventClick = onEventClick,
+                onCreateAt = onCreateAt,
             )
         }
     }
@@ -276,6 +307,8 @@ private fun DaySuccess(
     topSectionColor: Color,
     scrollState: ScrollState,
     allDayHeight: Dp,
+    onEventClick: (EventInstance) -> Unit,
+    onCreateAt: (LocalDate, Int) -> Unit,
 ) {
     Column(modifier = Modifier.fillMaxSize()) {
         // All-day strip collapses to nothing when the day has no all-day events,
@@ -283,6 +316,7 @@ private fun DaySuccess(
         AllDayStrip(
             state = state,
             height = allDayHeight,
+            onEventClick = onEventClick,
             modifier = Modifier
                 .fillMaxWidth()
                 .background(topSectionColor),
@@ -290,7 +324,12 @@ private fun DaySuccess(
         // Breathing room between the (colour-shifting) top section and the
         // scrolling timeline below.
         Spacer(Modifier.height(8.dp))
-        Timeline(state = state, scrollState = scrollState)
+        Timeline(
+            state = state,
+            scrollState = scrollState,
+            onEventClick = onEventClick,
+            onCreateAt = onCreateAt,
+        )
     }
 }
 
@@ -337,6 +376,7 @@ private fun DayTopBar(
 private fun AllDayStrip(
     state: DayUiState.Success,
     height: Dp,
+    onEventClick: (EventInstance) -> Unit,
     modifier: Modifier = Modifier,
 ) {
     val dark = isSystemInDarkTheme()
@@ -364,6 +404,7 @@ private fun AllDayStrip(
                 AllDayBar(
                     event = span.event,
                     dark = dark,
+                    onClick = { onEventClick(span.event) },
                     modifier = Modifier
                         .offset(y = ALL_DAY_ROW_HEIGHT * span.lane)
                         .width(barWidth)
@@ -376,11 +417,17 @@ private fun AllDayStrip(
 }
 
 @Composable
-private fun AllDayBar(event: EventInstance, dark: Boolean, modifier: Modifier = Modifier) {
+private fun AllDayBar(
+    event: EventInstance,
+    dark: Boolean,
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
     val title = event.title.ifBlank { stringResource(R.string.event_untitled) }
     Box(
         modifier = modifier
             .background(pastelize(event.color, dark), RoundedCornerShape(4.dp))
+            .clickable(onClick = onClick)
             .padding(horizontal = 6.dp, vertical = 2.dp)
             .semantics { contentDescription = title },
         contentAlignment = Alignment.CenterStart,
@@ -396,7 +443,12 @@ private fun AllDayBar(event: EventInstance, dark: Boolean, modifier: Modifier =
 }
 
 @Composable
-private fun Timeline(state: DayUiState.Success, scrollState: ScrollState) {
+private fun Timeline(
+    state: DayUiState.Success,
+    scrollState: ScrollState,
+    onEventClick: (EventInstance) -> Unit,
+    onCreateAt: (LocalDate, Int) -> Unit,
+) {
     val totalHeight = HOUR_HEIGHT * 24
     val dark = isSystemInDarkTheme()
 
@@ -443,6 +495,9 @@ private fun Timeline(state: DayUiState.Success, scrollState: ScrollState) {
                 DayColumnCard(
                     blocks = state.timed,
                     dark = dark,
+                    date = state.date,
+                    onEventClick = onEventClick,
+                    onCreateAt = onCreateAt,
                     modifier = Modifier
                         .fillMaxWidth()
                         .height(totalHeight),
@@ -456,8 +511,12 @@ private fun Timeline(state: DayUiState.Success, scrollState: ScrollState) {
 private fun DayColumnCard(
     blocks: List<TimedBlock>,
     dark: Boolean,
+    date: LocalDate,
+    onEventClick: (EventInstance) -> Unit,
+    onCreateAt: (LocalDate, Int) -> Unit,
     modifier: Modifier = Modifier,
 ) {
+    val hourPx = with(LocalDensity.current) { HOUR_HEIGHT.toPx() }
     Card(
         // Plain rectangular column — the soft corners come from the outer
         // rounded scroll viewport, so inner rounding would look odd at the edges.
@@ -467,7 +526,19 @@ private fun DayColumnCard(
         ),
         modifier = modifier,
     ) {
-        BoxWithConstraints(modifier = Modifier.fillMaxSize()) {
+        BoxWithConstraints(
+            modifier = Modifier
+                .fillMaxSize()
+                // Tap an empty slot to create an event there. Taps on event
+                // blocks are consumed by their own click handler first, so this
+                // only fires on the column background. Snaps to the tapped hour.
+                .pointerInput(date) {
+                    detectTapGestures { offset ->
+                        val hour = (offset.y / hourPx).toInt().coerceIn(0, 23)
+                        onCreateAt(date, hour * 60)
+                    }
+                },
+        ) {
             val colWidth = maxWidth
             blocks.forEach { block ->
                 val laneWidth = colWidth / block.laneCount
@@ -477,6 +548,7 @@ private fun DayColumnCard(
                 EventBlock(
                     block = block,
                     dark = dark,
+                    onClick = { onEventClick(block.event) },
                     modifier = Modifier
                         .offset(x = laneWidth * block.lane, y = top)
                         .width(laneWidth)
@@ -492,6 +564,7 @@ private fun DayColumnCard(
 private fun EventBlock(
     block: TimedBlock,
     dark: Boolean,
+    onClick: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
     val title = block.event.title.ifBlank { stringResource(R.string.event_untitled) }
@@ -500,6 +573,7 @@ private fun EventBlock(
     Box(
         modifier = modifier
             .background(pastelize(block.event.color, dark), RoundedCornerShape(4.dp))
+            .clickable(onClick = onClick)
             .padding(horizontal = 4.dp, vertical = 2.dp)
             .semantics { contentDescription = "$title, $timeLabel" },
     ) {

app/src/main/java/de/jeanlucmakiola/calendula/ui/day/DayViewModel.kt

@@ -78,6 +78,11 @@ class DayViewModel @Inject constructor(
         _date.value = todayDate
     }
 
+    /** Jump to a specific date (e.g. when opened from the month grid). */
+    fun goToDate(date: LocalDate) {
+        _date.value = date
+    }
+
     private fun buildState(
         day: LocalDate,
         calendars: List<CalendarSource>,

app/src/main/java/de/jeanlucmakiola/calendula/ui/detail/EventDetailScreen.kt

@@ -0,0 +1,826 @@
+package de.jeanlucmakiola.calendula.ui.detail
+
+import android.Manifest
+import android.content.ActivityNotFoundException
+import android.content.Context
+import android.content.Intent
+import android.content.pm.PackageManager
+import android.net.Uri
+import androidx.activity.compose.BackHandler
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.ExperimentalLayoutApi
+import androidx.compose.foundation.layout.FlowRow
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material.icons.automirrored.filled.Notes
+import androidx.compose.material.icons.filled.CalendarMonth
+import androidx.compose.material.icons.filled.Delete
+import androidx.compose.material.icons.filled.Edit
+import androidx.compose.material.icons.filled.Notifications
+import androidx.compose.material.icons.filled.People
+import androidx.compose.material.icons.filled.Place
+import androidx.compose.material.icons.filled.Public
+import androidx.compose.material.icons.filled.Repeat
+import androidx.compose.material.icons.filled.Schedule
+import androidx.compose.material.icons.filled.Share
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.SnackbarHost
+import androidx.compose.material3.SnackbarHostState
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.TopAppBarDefaults
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.platform.LocalContext
+import androidx.core.content.ContextCompat
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.AnnotatedString
+import androidx.compose.ui.text.LinkAnnotation
+import androidx.compose.ui.text.SpanStyle
+import androidx.compose.ui.text.TextLinkStyles
+import androidx.compose.ui.text.buildAnnotatedString
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextDecoration
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.domain.AccessLevel
+import de.jeanlucmakiola.calendula.domain.Attendee
+import de.jeanlucmakiola.calendula.domain.AttendeeRelationship
+import de.jeanlucmakiola.calendula.domain.AttendeeStatus
+import de.jeanlucmakiola.calendula.domain.AttendeeType
+import de.jeanlucmakiola.calendula.domain.Availability
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.domain.EventStatus
+import de.jeanlucmakiola.calendula.domain.RecurringWriteScope
+import de.jeanlucmakiola.calendula.domain.Reminder
+import de.jeanlucmakiola.calendula.ui.common.CalendarFailure
+import de.jeanlucmakiola.calendula.ui.common.OptionCard
+import de.jeanlucmakiola.calendula.ui.common.currentLocale
+import de.jeanlucmakiola.calendula.ui.common.pastelize
+import de.jeanlucmakiola.calendula.ui.common.recurrenceText
+import de.jeanlucmakiola.calendula.ui.common.reminderLeadTimeLabel
+import kotlinx.coroutines.launch
+import kotlinx.datetime.TimeZone
+import java.time.ZoneId
+import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
+import java.time.format.TextStyle as JavaTextStyle
+import java.util.Locale
+import kotlin.time.Duration.Companion.seconds
+import kotlin.time.Instant
+
+/**
+ * Full-screen event detail (spec S4, realised as a navigation destination
+ * rather than a bottom sheet — MD3 list→detail pattern). Back gesture and the
+ * top-bar arrow both return to the calendar. Events in writable calendars can
+ * be deleted (v1.1) and edited (v1.3) from here; [onEdit] opens the shared
+ * event form for this occurrence — for recurring events the form asks how
+ * far the change reaches when saving.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun EventDetailScreen(
+    eventId: Long,
+    beginMillis: Long,
+    endMillis: Long,
+    onBack: () -> Unit,
+    onEdit: () -> Unit,
+    viewModel: EventDetailViewModel = hiltViewModel(),
+) {
+    LaunchedEffect(eventId, beginMillis, endMillis) {
+        viewModel.open(eventId, beginMillis, endMillis)
+    }
+    val state by viewModel.state.collectAsStateWithLifecycle()
+    val deleteState by viewModel.deleteState.collectAsStateWithLifecycle()
+
+    BackHandler(onBack = onBack)
+
+    val context = LocalContext.current
+    val scope = rememberCoroutineScope()
+    val snackbarHostState = remember { SnackbarHostState() }
+    var showDeleteDialog by rememberSaveable { mutableStateOf(false) }
+
+    // Sharing is read-only, so it needs no WRITE_CALENDAR upgrade. The VM stages
+    // an .ics in the cache and hands back a content Uri for the chooser.
+    val shareFailedMessage = stringResource(R.string.event_share_failed)
+    val shareChooserTitle = stringResource(R.string.event_share_chooser_title)
+    val onShareClick = {
+        scope.launch {
+            val uri = viewModel.shareUri()
+            val sent = uri != null && runCatching {
+                val send = Intent(Intent.ACTION_SEND).apply {
+                    type = "text/calendar"
+                    putExtra(Intent.EXTRA_STREAM, uri)
+                    addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
+                }
+                context.startActivity(Intent.createChooser(send, shareChooserTitle))
+            }.isSuccess
+            if (!sent) snackbarHostState.showSnackbar(shareFailedMessage)
+        }
+        Unit
+    }
+
+    // v1.0 installs only hold READ_CALENDAR; the first write asks for the
+    // upgrade in place. Granting continues straight into the tapped action.
+    var pendingEdit by remember { mutableStateOf(false) }
+    val writePermissionLauncher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.RequestPermission(),
+    ) { granted ->
+        if (granted) {
+            if (pendingEdit) onEdit() else showDeleteDialog = true
+        }
+        pendingEdit = false
+    }
+    val hasWritePermission = {
+        ContextCompat.checkSelfPermission(
+            context,
+            Manifest.permission.WRITE_CALENDAR,
+        ) == PackageManager.PERMISSION_GRANTED
+    }
+    val onDeleteClick = {
+        if (hasWritePermission()) {
+            showDeleteDialog = true
+        } else {
+            pendingEdit = false
+            writePermissionLauncher.launch(Manifest.permission.WRITE_CALENDAR)
+        }
+    }
+    val onEditClick = {
+        if (hasWritePermission()) {
+            onEdit()
+        } else {
+            pendingEdit = true
+            writePermissionLauncher.launch(Manifest.permission.WRITE_CALENDAR)
+        }
+    }
+
+    val deleteFailedMessage = stringResource(R.string.event_delete_failed)
+    val writeDeniedMessage = stringResource(R.string.event_delete_write_denied)
+    LaunchedEffect(deleteState) {
+        when (deleteState) {
+            DeleteUiState.Deleted -> {
+                viewModel.consumeDeleteResult()
+                onBack()
+            }
+            DeleteUiState.Failed -> {
+                viewModel.consumeDeleteResult()
+                snackbarHostState.showSnackbar(deleteFailedMessage)
+            }
+            DeleteUiState.NeedsPermission -> {
+                viewModel.consumeDeleteResult()
+                snackbarHostState.showSnackbar(writeDeniedMessage)
+            }
+            DeleteUiState.Idle, DeleteUiState.Deleting -> Unit
+        }
+    }
+
+    Scaffold(
+        snackbarHost = { SnackbarHost(snackbarHostState) },
+        topBar = {
+            TopAppBar(
+                title = {},
+                navigationIcon = {
+                    IconButton(onClick = onBack) {
+                        Icon(
+                            imageVector = Icons.AutoMirrored.Filled.ArrowBack,
+                            contentDescription = stringResource(R.string.event_detail_back),
+                        )
+                    }
+                },
+                actions = {
+                    val s = state
+                    // Share works for any loaded event — it only reads the event.
+                    if (s is EventDetailUiState.Success) {
+                        IconButton(onClick = onShareClick) {
+                            Icon(
+                                imageVector = Icons.Default.Share,
+                                contentDescription = stringResource(R.string.event_detail_share),
+                            )
+                        }
+                    }
+                    // Edit/delete need a writable calendar — WebCal subscriptions,
+                    // birthday calendars etc. are read-only at the provider level.
+                    if (s is EventDetailUiState.Success && s.canModify) {
+                        IconButton(
+                            onClick = onEditClick,
+                            enabled = deleteState != DeleteUiState.Deleting,
+                        ) {
+                            Icon(
+                                imageVector = Icons.Default.Edit,
+                                contentDescription = stringResource(R.string.event_detail_edit),
+                            )
+                        }
+                        IconButton(
+                            onClick = onDeleteClick,
+                            enabled = deleteState != DeleteUiState.Deleting,
+                        ) {
+                            Icon(
+                                imageVector = Icons.Default.Delete,
+                                contentDescription = stringResource(R.string.event_detail_delete),
+                            )
+                        }
+                    }
+                },
+                colors = TopAppBarDefaults.topAppBarColors(
+                    containerColor = MaterialTheme.colorScheme.surface,
+                ),
+            )
+        },
+    ) { innerPadding ->
+        val contentModifier = Modifier
+            .fillMaxSize()
+            .padding(innerPadding)
+        when (val s = state) {
+            EventDetailUiState.Loading -> EventDetailLoading(contentModifier)
+            is EventDetailUiState.Failure -> CalendarFailure(
+                reason = s.reason,
+                onRetry = viewModel::retry,
+            )
+            is EventDetailUiState.Success -> EventDetailContent(s, contentModifier)
+        }
+    }
+
+    val loaded = state
+    if (showDeleteDialog && loaded is EventDetailUiState.Success) {
+        DeleteEventDialog(
+            isRecurring = !loaded.detail.rrule.isNullOrBlank(),
+            onConfirm = { scope ->
+                showDeleteDialog = false
+                viewModel.delete(scope)
+            },
+            onDismiss = { showDeleteDialog = false },
+        )
+    }
+}
+
+/**
+ * Delete confirmation. Recurring events choose between cancelling just the
+ * tapped occurrence (default), truncating the series from it onwards, and
+ * removing the whole series.
+ */
+@Composable
+private fun DeleteEventDialog(
+    isRecurring: Boolean,
+    onConfirm: (RecurringWriteScope) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    var scope by rememberSaveable { mutableStateOf(RecurringWriteScope.ThisEvent) }
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = {
+            Text(
+                stringResource(
+                    if (isRecurring) R.string.event_delete_recurring_title
+                    else R.string.event_delete_title,
+                ),
+            )
+        },
+        text = {
+            if (isRecurring) {
+                Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                    OptionCard(
+                        label = stringResource(R.string.event_delete_option_occurrence),
+                        onClick = { scope = RecurringWriteScope.ThisEvent },
+                        selected = scope == RecurringWriteScope.ThisEvent,
+                    )
+                    OptionCard(
+                        label = stringResource(R.string.event_delete_option_following),
+                        onClick = { scope = RecurringWriteScope.ThisAndFollowing },
+                        selected = scope == RecurringWriteScope.ThisAndFollowing,
+                    )
+                    OptionCard(
+                        label = stringResource(R.string.event_delete_option_series),
+                        onClick = { scope = RecurringWriteScope.AllEvents },
+                        selected = scope == RecurringWriteScope.AllEvents,
+                    )
+                }
+            } else {
+                Text(stringResource(R.string.event_delete_body))
+            }
+        },
+        confirmButton = {
+            TextButton(
+                onClick = { onConfirm(if (isRecurring) scope else RecurringWriteScope.AllEvents) },
+            ) {
+                Text(
+                    text = stringResource(R.string.event_detail_delete),
+                    color = MaterialTheme.colorScheme.error,
+                )
+            }
+        },
+        dismissButton = {
+            TextButton(onClick = onDismiss) {
+                Text(stringResource(R.string.dialog_cancel))
+            }
+        },
+    )
+}
+
+
+@Composable
+private fun EventDetailContent(state: EventDetailUiState.Success, modifier: Modifier = Modifier) {
+    val detail = state.detail
+    val instance = detail.instance
+    val dark = isSystemInDarkTheme()
+    val locale = currentDetailLocale()
+    val accent = pastelize(instance.color, dark)
+
+    Column(
+        modifier = modifier
+            .verticalScroll(rememberScrollState())
+            .padding(start = 24.dp, end = 24.dp, top = 8.dp, bottom = 40.dp),
+    ) {
+        // Title row: title on the left, a "Free" pill pinned top-right when the
+        // event doesn't block your time. Busy is the default for nearly every
+        // event, so it's left implicit — only Free is worth surfacing. A
+        // cancelled event strikes through its title.
+        Row(verticalAlignment = Alignment.Top) {
+            Text(
+                text = instance.title.ifBlank { stringResource(R.string.event_untitled) },
+                style = MaterialTheme.typography.headlineMedium,
+                fontWeight = FontWeight.SemiBold,
+                textDecoration = if (detail.status == EventStatus.Cancelled) {
+                    TextDecoration.LineThrough
+                } else {
+                    null
+                },
+                modifier = Modifier.weight(1f),
+            )
+            if (detail.availability == Availability.Free) {
+                Spacer(Modifier.width(12.dp))
+                InfoChip(
+                    text = stringResource(R.string.event_availability_free),
+                    modifier = Modifier.padding(top = 6.dp),
+                )
+            }
+        }
+        Spacer(Modifier.height(10.dp))
+        Box(
+            modifier = Modifier
+                .width(48.dp)
+                .height(3.dp)
+                .background(accent, RoundedCornerShape(2.dp)),
+        )
+
+        // Status / access chips — shown only when noteworthy (Confirmed status
+        // and Default/Public access are the silent norm).
+        val hasStatusChips = detail.status != EventStatus.Confirmed ||
+            detail.accessLevel == AccessLevel.Private ||
+            detail.accessLevel == AccessLevel.Confidential
+        if (hasStatusChips) {
+            Spacer(Modifier.height(16.dp))
+            StatusChips(detail.status, detail.accessLevel)
+        }
+
+        Spacer(Modifier.height(20.dp))
+
+        // Every piece of info shares one card design: a tonal container with a
+        // leading icon in the gutter and the value to the right. 12dp gaps stack
+        // them cleanly.
+        val gap = 12.dp
+
+        // "When" — date/all-day plus the time range.
+        val (whenPrimary, whenSecondary) = formatWhen(instance, TimeZone.currentSystemDefault(), locale)
+        DetailCard(icon = Icons.Default.Schedule, iconContentDescription = null) {
+            Text(text = whenPrimary, style = MaterialTheme.typography.titleMedium)
+            if (whenSecondary != null) {
+                Spacer(Modifier.height(2.dp))
+                Text(
+                    text = whenSecondary,
+                    style = MaterialTheme.typography.bodyMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            }
+        }
+
+        // Time zone — only when the event is timed and pinned to a zone other
+        // than the device's, so cross-zone events read unambiguously.
+        foreignTimeZoneLabel(detail.eventTimezone, instance.isAllDay, locale)?.let { tzLabel ->
+            Spacer(Modifier.height(gap))
+            DetailCard(
+                icon = Icons.Default.Public,
+                iconContentDescription = stringResource(R.string.event_detail_timezone),
+            ) {
+                Text(text = tzLabel, style = MaterialTheme.typography.titleMedium)
+            }
+        }
+
+        // Calendar — icon tinted in the calendar colour conveys identity, so no
+        // separate colour dot is needed.
+        Spacer(Modifier.height(gap))
+        DetailCard(
+            icon = Icons.Default.CalendarMonth,
+            iconTint = accent,
+            iconContentDescription = stringResource(R.string.event_detail_calendar),
+        ) {
+            Text(
+                text = state.calendarName ?: stringResource(R.string.event_detail_calendar_unknown),
+                style = MaterialTheme.typography.titleMedium,
+            )
+        }
+
+        // Location (conditional, tap → maps).
+        instance.location?.takeIf { it.isNotBlank() }?.let { location ->
+            val context = LocalContext.current
+            Spacer(Modifier.height(gap))
+            DetailCard(
+                icon = Icons.Default.Place,
+                iconContentDescription = stringResource(R.string.event_detail_location),
+            ) {
+                Text(
+                    text = location,
+                    style = MaterialTheme.typography.titleMedium,
+                    color = MaterialTheme.colorScheme.primary,
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .clickable { openInMaps(context, location) }
+                        .padding(vertical = 2.dp),
+                )
+            }
+        }
+
+        // Description (conditional). URLs are auto-linked.
+        detail.description?.takeIf { it.isNotBlank() }?.let { description ->
+            Spacer(Modifier.height(gap))
+            DetailCard(
+                icon = Icons.AutoMirrored.Filled.Notes,
+                iconContentDescription = stringResource(R.string.event_detail_description),
+            ) {
+                Text(
+                    text = linkifyUrls(description, MaterialTheme.colorScheme.primary),
+                    style = MaterialTheme.typography.bodyMedium,
+                )
+            }
+        }
+
+        // Attendees (conditional). The user's own response leads the list, then
+        // each attendee with their role and reply.
+        detail.attendees.takeIf { it.isNotEmpty() }?.let { attendees ->
+            Spacer(Modifier.height(gap))
+            DetailCard(
+                icon = Icons.Default.People,
+                iconContentDescription = stringResource(R.string.event_detail_attendees),
+            ) {
+                if (detail.selfStatus != AttendeeStatus.Unknown) {
+                    Text(
+                        text = stringResource(
+                            R.string.event_detail_self_response,
+                            stringResource(attendeeStatusLabel(detail.selfStatus)),
+                        ),
+                        style = MaterialTheme.typography.labelLarge,
+                        color = MaterialTheme.colorScheme.primary,
+                    )
+                    Spacer(Modifier.height(8.dp))
+                }
+                attendees.forEach { AttendeeRow(it) }
+            }
+        }
+
+        // Reminders (conditional) — list each lead time before the event.
+        detail.reminders.takeIf { it.isNotEmpty() }?.let { reminders ->
+            Spacer(Modifier.height(gap))
+            DetailCard(
+                icon = Icons.Default.Notifications,
+                iconContentDescription = stringResource(R.string.event_detail_reminders),
+            ) {
+                reminders
+                    .distinctBy { it.minutes }
+                    .sortedBy { it.minutes }
+                    .forEach { reminder ->
+                        Text(
+                            text = reminderLeadText(reminder),
+                            style = MaterialTheme.typography.titleMedium,
+                            modifier = Modifier.padding(vertical = 2.dp),
+                        )
+                    }
+            }
+        }
+
+        // Recurrence (conditional) — humanised from the RRULE.
+        detail.rrule?.takeIf { it.isNotBlank() }?.let { rrule ->
+            Spacer(Modifier.height(gap))
+            DetailCard(
+                icon = Icons.Default.Repeat,
+                iconContentDescription = stringResource(R.string.event_detail_recurrence),
+            ) {
+                Text(
+                    text = recurrenceText(rrule, locale),
+                    style = MaterialTheme.typography.titleMedium,
+                )
+            }
+        }
+    }
+}
+
+/** One info card: tonal container, leading icon in the gutter, value to the right. */
+@Composable
+private fun DetailCard(
+    icon: ImageVector,
+    iconContentDescription: String?,
+    iconTint: Color = MaterialTheme.colorScheme.onSurfaceVariant,
+    content: @Composable ColumnScope.() -> Unit,
+) {
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        shape = RoundedCornerShape(16.dp),
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Row(
+            modifier = Modifier.padding(16.dp),
+            verticalAlignment = Alignment.CenterVertically,
+        ) {
+            Icon(
+                imageVector = icon,
+                contentDescription = iconContentDescription,
+                tint = iconTint,
+                modifier = Modifier.size(24.dp),
+            )
+            Spacer(Modifier.width(16.dp))
+            Column(modifier = Modifier.weight(1f), content = content)
+        }
+    }
+}
+
+@Composable
+private fun AttendeeRow(attendee: Attendee) {
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(vertical = 3.dp),
+        horizontalArrangement = Arrangement.SpaceBetween,
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Column(modifier = Modifier.weight(1f)) {
+            Text(
+                text = attendee.name.ifBlank { attendee.email.orEmpty() },
+                style = MaterialTheme.typography.bodyMedium,
+            )
+            attendeeRoleLabel(attendee)?.let { roleRes ->
+                Text(
+                    text = stringResource(roleRes),
+                    style = MaterialTheme.typography.labelSmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            }
+        }
+        Spacer(Modifier.width(8.dp))
+        Text(
+            text = stringResource(attendeeStatusLabel(attendee.status)),
+            style = MaterialTheme.typography.labelSmall,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+    }
+}
+
+/** Status / access pills shown directly under the title accent. */
+@OptIn(ExperimentalLayoutApi::class)
+@Composable
+private fun StatusChips(status: EventStatus, accessLevel: AccessLevel) {
+    FlowRow(
+        horizontalArrangement = Arrangement.spacedBy(8.dp),
+        verticalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        when (status) {
+            EventStatus.Cancelled -> InfoChip(
+                text = stringResource(R.string.event_status_cancelled),
+                container = MaterialTheme.colorScheme.errorContainer,
+                content = MaterialTheme.colorScheme.onErrorContainer,
+            )
+            EventStatus.Tentative -> InfoChip(
+                text = stringResource(R.string.event_status_tentative),
+                container = MaterialTheme.colorScheme.tertiaryContainer,
+                content = MaterialTheme.colorScheme.onTertiaryContainer,
+            )
+            EventStatus.Confirmed -> Unit
+        }
+
+        when (accessLevel) {
+            AccessLevel.Private -> InfoChip(text = stringResource(R.string.event_access_private))
+            AccessLevel.Confidential ->
+                InfoChip(text = stringResource(R.string.event_access_confidential))
+            AccessLevel.Default, AccessLevel.Public -> Unit
+        }
+    }
+}
+
+@Composable
+private fun InfoChip(
+    text: String,
+    modifier: Modifier = Modifier,
+    container: Color = MaterialTheme.colorScheme.surfaceContainerHighest,
+    content: Color = MaterialTheme.colorScheme.onSurfaceVariant,
+) {
+    Surface(color = container, shape = RoundedCornerShape(8.dp), modifier = modifier) {
+        Text(
+            text = text,
+            style = MaterialTheme.typography.labelMedium,
+            color = content,
+            modifier = Modifier.padding(horizontal = 10.dp, vertical = 5.dp),
+        )
+    }
+}
+
+@Composable
+private fun EventDetailLoading(modifier: Modifier = Modifier) {
+    Column(modifier = modifier.padding(start = 24.dp, end = 24.dp, top = 16.dp)) {
+        SkeletonBar(widthFraction = 0.7f, height = 32.dp)
+        Spacer(Modifier.height(24.dp))
+        SkeletonBar(widthFraction = 1f, height = 64.dp)
+        Spacer(Modifier.height(28.dp))
+        SkeletonBar(widthFraction = 0.35f, height = 14.dp)
+        Spacer(Modifier.height(8.dp))
+        SkeletonBar(widthFraction = 0.6f, height = 16.dp)
+        Spacer(Modifier.height(24.dp))
+        SkeletonBar(widthFraction = 0.35f, height = 14.dp)
+        Spacer(Modifier.height(8.dp))
+        SkeletonBar(widthFraction = 0.8f, height = 16.dp)
+    }
+}
+
+@Composable
+private fun SkeletonBar(widthFraction: Float, height: Dp) {
+    Box(
+        modifier = Modifier
+            .fillMaxWidth(widthFraction)
+            .height(height)
+            .background(
+                MaterialTheme.colorScheme.surfaceContainerHighest,
+                RoundedCornerShape(8.dp),
+            ),
+    )
+}
+
+// --- helpers -------------------------------------------------------------
+
+// Observable locale read (shared helper) — avoids NonObservableLocale /
+// LocalContextConfigurationRead lint by going through LocalConfiguration.
+@Composable
+private fun currentDetailLocale(): Locale = currentLocale()
+
+private fun attendeeStatusLabel(status: AttendeeStatus): Int = when (status) {
+    AttendeeStatus.Accepted -> R.string.event_attendee_accepted
+    AttendeeStatus.Declined -> R.string.event_attendee_declined
+    AttendeeStatus.Tentative -> R.string.event_attendee_tentative
+    AttendeeStatus.NeedsAction -> R.string.event_attendee_needs_action
+    AttendeeStatus.Unknown -> R.string.event_attendee_unknown
+}
+
+/**
+ * The role badge shown under an attendee's name. Organizer wins over type;
+ * required attendees (the common case) get no badge to keep the list quiet.
+ */
+private fun attendeeRoleLabel(attendee: Attendee): Int? = when {
+    attendee.relationship == AttendeeRelationship.Organizer -> R.string.event_attendee_organizer
+    attendee.type == AttendeeType.Optional -> R.string.event_attendee_optional
+    attendee.type == AttendeeType.Resource -> R.string.event_attendee_resource
+    else -> null
+}
+
+/** Humanise a reminder's lead time, e.g. "10 minutes before" / "At time of event". */
+@Composable
+private fun reminderLeadText(reminder: Reminder): String = reminderLeadTimeLabel(reminder.minutes)
+
+/**
+ * A localized label for [tz] (e.g. "Central European Time (Europe/Berlin)"),
+ * but only when the event is timed and pinned to a zone different from the
+ * device's. Returns null when there's nothing worth showing.
+ */
+private fun foreignTimeZoneLabel(tz: String?, isAllDay: Boolean, locale: Locale): String? {
+    if (isAllDay || tz.isNullOrBlank()) return null
+    val deviceZone = ZoneId.systemDefault().id
+    if (tz == deviceZone) return null
+    return try {
+        val zone = ZoneId.of(tz)
+        val name = zone.getDisplayName(JavaTextStyle.FULL, locale)
+        if (name == tz) tz else "$name ($tz)"
+    } catch (e: Exception) {
+        tz
+    }
+}
+
+/** Wrap http(s) URLs in [text] as tappable links tinted [linkColor]. */
+@Composable
+private fun linkifyUrls(text: String, linkColor: Color): AnnotatedString = remember(text, linkColor) {
+    val regex = Regex("""https?://\S+""")
+    val styles = TextLinkStyles(
+        style = SpanStyle(color = linkColor, textDecoration = TextDecoration.Underline),
+    )
+    buildAnnotatedString {
+        append(text)
+        for (match in regex.findAll(text)) {
+            // Trim trailing punctuation that commonly abuts a URL in prose.
+            val raw = match.value
+            val url = raw.trimEnd('.', ',', ';', ':', '!', '?', ')', ']', '"', '\'')
+            val end = match.range.first + url.length
+            addLink(LinkAnnotation.Url(url, styles), match.range.first, end)
+        }
+    }
+}
+
+/**
+ * Format an event's time into a primary line (date, or "All day") and an
+ * optional secondary line (time range). Multi-day timed events collapse into a
+ * single primary line spanning both ends.
+ */
+@Composable
+private fun formatWhen(
+    instance: EventInstance,
+    zone: TimeZone,
+    locale: Locale,
+): Pair<String, String?> {
+    val zid = ZoneId.of(zone.id)
+    val dateFull = DateTimeFormatter.ofLocalizedDate(FormatStyle.FULL).withLocale(locale)
+    val dateMedium = DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM).withLocale(locale)
+    val timeShort = DateTimeFormatter.ofLocalizedTime(FormatStyle.SHORT).withLocale(locale)
+
+    val startLdt = instance.start.toJavaLocalDateTime(zid)
+    val allDayLabel = stringResource(R.string.event_detail_all_day)
+
+    if (instance.isAllDay) {
+        // All-day events live at UTC midnights with an exclusive end. Resolve
+        // the covered dates in UTC — not the device zone, which would shift the
+        // midnight boundaries off the intended date (east of UTC pushes the
+        // end past the last day; west of UTC pulls the start back) — and step
+        // the end back to the last covered day so a one-day event reads as a
+        // single date.
+        val utc = ZoneId.of("UTC")
+        val startDate = instance.start.toJavaLocalDateTime(utc).toLocalDate()
+        val lastDate = (instance.end - 1.seconds).toJavaLocalDateTime(utc).toLocalDate()
+        return if (startDate == lastDate) {
+            allDayLabel to dateFull.format(startDate)
+        } else {
+            allDayLabel to "${dateMedium.format(startDate)} – ${dateMedium.format(lastDate)}"
+        }
+    }
+
+    val endLdt = instance.end.toJavaLocalDateTime(zid)
+    return if (startLdt.toLocalDate() == endLdt.toLocalDate()) {
+        dateFull.format(startLdt.toLocalDate()) to
+            "${timeShort.format(startLdt)} – ${timeShort.format(endLdt)}"
+    } else {
+        val start = "${dateMedium.format(startLdt.toLocalDate())} ${timeShort.format(startLdt)}"
+        val end = "${dateMedium.format(endLdt.toLocalDate())} ${timeShort.format(endLdt)}"
+        "$start – $end" to null
+    }
+}
+
+private fun Instant.toJavaLocalDateTime(zid: ZoneId): java.time.LocalDateTime =
+    java.time.LocalDateTime.ofInstant(java.time.Instant.ofEpochMilli(toEpochMilliseconds()), zid)
+
+/** Open a maps intent for [query]; fall back to a web maps URL if no app handles geo:. */
+private fun openInMaps(context: Context, query: String) {
+    val encoded = Uri.encode(query)
+    val geo = Intent(Intent.ACTION_VIEW, Uri.parse("geo:0,0?q=$encoded"))
+    try {
+        context.startActivity(geo)
+    } catch (e: ActivityNotFoundException) {
+        val web = Intent(
+            Intent.ACTION_VIEW,
+            Uri.parse("https://www.google.com/maps/search/?api=1&query=$encoded"),
+        )
+        try {
+            context.startActivity(web)
+        } catch (e2: ActivityNotFoundException) {
+            // No browser either — nothing sensible to do; swallow.
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/detail/EventDetailUiState.kt

@@ -0,0 +1,32 @@
+package de.jeanlucmakiola.calendula.ui.detail
+
+import de.jeanlucmakiola.calendula.domain.EventDetail
+import de.jeanlucmakiola.calendula.domain.FailureReason
+
+/**
+ * UI state for the event-detail screen (spec S4).
+ */
+sealed interface EventDetailUiState {
+    data object Loading : EventDetailUiState
+    data class Failure(val reason: FailureReason) : EventDetailUiState
+    data class Success(
+        val detail: EventDetail,
+        /** Display name of the owning calendar, null if it can't be resolved. */
+        val calendarName: String?,
+        /** Whether the owning calendar allows modifying events (shows edit/delete). */
+        val canModify: Boolean = false,
+    ) : EventDetailUiState
+}
+
+/**
+ * One-shot state of a delete request, separate from the screen state so a
+ * failed delete leaves the loaded detail visible.
+ */
+sealed interface DeleteUiState {
+    data object Idle : DeleteUiState
+    data object Deleting : DeleteUiState
+    data object Deleted : DeleteUiState
+    /** WRITE_CALENDAR was revoked between the tap and the provider call. */
+    data object NeedsPermission : DeleteUiState
+    data object Failed : DeleteUiState
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/detail/EventDetailViewModel.kt

@@ -0,0 +1,180 @@
+package de.jeanlucmakiola.calendula.ui.detail
+
+import android.net.Uri
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.calendar.NoSuchEventException
+import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.data.ics.IcsExporter
+import de.jeanlucmakiola.calendula.domain.FailureReason
+import de.jeanlucmakiola.calendula.domain.RecurringWriteScope
+import de.jeanlucmakiola.calendula.domain.ics.IcsWriter
+import de.jeanlucmakiola.calendula.domain.ics.toShareIcsEvent
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.withContext
+import kotlin.time.Clock
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOf
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import kotlin.coroutines.cancellation.CancellationException
+import kotlin.time.Instant
+import javax.inject.Inject
+
+/**
+ * Loads a single event's detail on demand for the bottom sheet (spec S4).
+ * The event id is set via [open]; the sheet observes [state].
+ */
+@OptIn(ExperimentalCoroutinesApi::class)
+@HiltViewModel
+class EventDetailViewModel @Inject constructor(
+    private val repository: CalendarRepository,
+    private val icsExporter: IcsExporter,
+    @IoDispatcher private val io: CoroutineDispatcher,
+) : ViewModel() {
+
+    private val _target = MutableStateFlow<Target?>(null)
+    // Bumped by retry() to re-run the load for the same target.
+    private val _reload = MutableStateFlow(0)
+
+    private val _deleteState = MutableStateFlow<DeleteUiState>(DeleteUiState.Idle)
+    val deleteState: StateFlow<DeleteUiState> = _deleteState.asStateFlow()
+
+    val state: StateFlow<EventDetailUiState> =
+        combine(_target, _reload) { target, _ -> target }
+            .flatMapLatest { target ->
+                if (target == null) {
+                    flowOf<EventDetailUiState>(EventDetailUiState.Loading)
+                } else {
+                    flow {
+                        emit(EventDetailUiState.Loading)
+                        emit(loadDetail(target))
+                    }
+                }
+            }
+            .flowOn(io)
+            .stateIn(
+                scope = viewModelScope,
+                started = SharingStarted.WhileSubscribed(5_000L),
+                initialValue = EventDetailUiState.Loading,
+            )
+
+    /**
+     * Open (or switch) to the tapped occurrence. [beginMillis]/[endMillis] are
+     * the occurrence's own times (from `CalendarContract.Instances`); they
+     * override the series DTSTART/DTEND so recurring events show the correct
+     * date instead of the first occurrence.
+     */
+    fun open(eventId: Long, beginMillis: Long, endMillis: Long) {
+        _target.value = Target(eventId, beginMillis, endMillis)
+    }
+
+    /** Re-run the current load after a failure. */
+    fun retry() {
+        _reload.value += 1
+    }
+
+    /**
+     * Delete the open event. [scope] is meaningful only for recurring events
+     * (one-off events always pass [RecurringWriteScope.AllEvents]). Result
+     * lands in [deleteState]; the screen consumes it via [consumeDeleteResult].
+     */
+    fun delete(scope: RecurringWriteScope) {
+        val target = _target.value ?: return
+        if (_deleteState.value == DeleteUiState.Deleting) return
+        viewModelScope.launch {
+            _deleteState.value = DeleteUiState.Deleting
+            _deleteState.value = try {
+                when (scope) {
+                    RecurringWriteScope.AllEvents ->
+                        repository.deleteEvent(target.eventId)
+                    RecurringWriteScope.ThisEvent ->
+                        repository.deleteOccurrence(target.eventId, target.beginMillis)
+                    RecurringWriteScope.ThisAndFollowing ->
+                        repository.deleteEventFromOccurrence(target.eventId, target.beginMillis)
+                }
+                DeleteUiState.Deleted
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: SecurityException) {
+                DeleteUiState.NeedsPermission
+            } catch (e: Exception) {
+                DeleteUiState.Failed
+            }
+        }
+    }
+
+    /** Reset [deleteState] after the screen handled a terminal result. */
+    fun consumeDeleteResult() {
+        _deleteState.value = DeleteUiState.Idle
+    }
+
+    /**
+     * Serialise the open event to a `.ics` cache file and return a shareable
+     * content Uri (for an ACTION_SEND), or null when nothing is loaded or the
+     * write fails. The event is exported as a one-off (see [toShareIcsEvent]).
+     */
+    suspend fun shareUri(): Uri? {
+        val detail = (state.value as? EventDetailUiState.Success)?.detail ?: return null
+        return runCatching {
+            withContext(io) {
+                val ics = IcsWriter().writeCalendar(
+                    events = listOf(detail.toShareIcsEvent()),
+                    dtStamp = Clock.System.now(),
+                )
+                icsExporter.stageShareFile(shareFileName(detail.instance.title), ics)
+            }
+        }.getOrNull()
+    }
+
+    private suspend fun loadDetail(target: Target): EventDetailUiState = try {
+        val detail = repository.eventDetail(target.eventId)
+        // The Events row holds the series start; replace it with this
+        // occurrence's time so recurring events render correctly.
+        val corrected = detail.copy(
+            instance = detail.instance.copy(
+                start = Instant.fromEpochMilliseconds(target.beginMillis),
+                end = Instant.fromEpochMilliseconds(target.endMillis),
+            ),
+        )
+        val calendar = repository.calendars().first()
+            .firstOrNull { it.id == corrected.instance.calendarId }
+        EventDetailUiState.Success(
+            detail = corrected,
+            calendarName = calendar?.displayName,
+            canModify = calendar?.canModifyContents == true,
+        )
+    } catch (e: CancellationException) {
+        throw e
+    } catch (e: NoSuchEventException) {
+        EventDetailUiState.Failure(FailureReason.EventNotFound)
+    } catch (e: SecurityException) {
+        EventDetailUiState.Failure(FailureReason.PermissionRevoked)
+    } catch (e: Exception) {
+        EventDetailUiState.Failure(FailureReason.ProviderUnavailable)
+    }
+
+    /** A tapped occurrence: the series [eventId] plus this occurrence's own times. */
+    private data class Target(val eventId: Long, val beginMillis: Long, val endMillis: Long)
+}
+
+/** A filesystem-safe `.ics` file name from an event title (or a fallback). */
+private fun shareFileName(title: String): String {
+    val base = title.trim()
+        .replace(Regex("""[^\p{L}\p{Nd} _-]"""), "")
+        .replace(' ', '_')
+        .take(40)
+        .ifBlank { "event" }
+    return "$base.ics"
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditUiState.kt

@@ -0,0 +1,69 @@
+package de.jeanlucmakiola.calendula.ui.edit
+
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventColorOption
+import de.jeanlucmakiola.calendula.domain.EventForm
+import de.jeanlucmakiola.calendula.domain.EventFormField
+import de.jeanlucmakiola.calendula.domain.EventFormProblem
+import de.jeanlucmakiola.calendula.domain.RecurringWriteScope
+
+/**
+ * UI state for the event form (v1.2: create; v1.3 reuses it for edit). Null
+ * form means the screen hasn't been opened yet.
+ */
+data class EventEditUiState(
+    /** The form with its calendar id resolved (picked > last used > first writable). */
+    val form: EventForm,
+    /** Calendars that accept writes — the only valid targets. */
+    val calendars: List<CalendarSource>,
+    /** Validation problems; empty until a save was attempted. */
+    val problems: Set<EventFormProblem>,
+    val saveState: SaveUiState,
+    /** Optional sections currently rendered (settings defaults ∪ revealed). */
+    val visibleFields: Set<EventFormField> = emptySet(),
+    /**
+     * Optional sections behind "more fields". Sections the current mode can't
+     * offer at all (recurrence while editing a single occurrence) appear in
+     * neither list.
+     */
+    val hiddenFields: List<EventFormField> = emptyList(),
+    /** True while editing an existing event (the calendar is then fixed). */
+    val isEditing: Boolean = false,
+    /**
+     * True while an edit changed the recurrence rule — the save-scope dialog
+     * then drops "only this event" (an exception row can't carry a rule).
+     */
+    val recurrenceChanged: Boolean = false,
+    /**
+     * The event-colour palette the resolved target calendar publishes; empty
+     * when it exposes none. Non-empty → the colour picker offers these swatches
+     * (written as a key, sync-safe); empty → see [colorMode].
+     */
+    val colorPalette: List<EventColorOption> = emptyList(),
+    /**
+     * Whether the user has opted into custom colours on calendars that publish
+     * no palette (a synced one may then drop the colour on sync). Mirrors the
+     * settings flag; ignored for local and palette-backed calendars.
+     */
+    val allowColorOnUnsupportedCalendars: Boolean = false,
+)
+
+/** One-shot state of a save request, mirroring DeleteUiState on the detail screen. */
+sealed interface SaveUiState {
+    data object Idle : SaveUiState
+    /** A dirty recurring event waits for the user to pick the write scope. */
+    data object AwaitingScope : SaveUiState
+    /**
+     * The event changed externally (sync) while the form was open; the save
+     * is parked with its chosen [scope] until the user picks overwrite,
+     * discard, or cancel.
+     */
+    data class AwaitingConflict(val scope: RecurringWriteScope) : SaveUiState
+    /** The event was deleted externally while the form was open. */
+    data object Gone : SaveUiState
+    data object Saving : SaveUiState
+    data object Saved : SaveUiState
+    /** WRITE_CALENDAR was revoked between the tap and the provider call. */
+    data object NeedsPermission : SaveUiState
+    data object Failed : SaveUiState
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditViewModel.kt

@@ -0,0 +1,479 @@
+package de.jeanlucmakiola.calendula.ui.edit
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.calendar.NoSuchEventException
+import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.data.prefs.resolveDefaultReminder
+import de.jeanlucmakiola.calendula.domain.AccessLevel
+import de.jeanlucmakiola.calendula.domain.Availability
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EditSnapshot
+import de.jeanlucmakiola.calendula.domain.EventColorOption
+import de.jeanlucmakiola.calendula.domain.EventForm
+import de.jeanlucmakiola.calendula.domain.EventFormField
+import de.jeanlucmakiola.calendula.domain.RecurringWriteScope
+import de.jeanlucmakiola.calendula.domain.populatedFields
+import de.jeanlucmakiola.calendula.domain.problems
+import de.jeanlucmakiola.calendula.domain.toEditSnapshot
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toInstant
+import kotlinx.datetime.toLocalDateTime
+import kotlin.coroutines.cancellation.CancellationException
+import kotlin.time.Clock
+import kotlin.time.Duration.Companion.hours
+import kotlin.time.Instant
+import javax.inject.Inject
+
+/**
+ * Holds the event form being composed. The form's calendar id resolves to
+ * (user pick > last used > first writable); the resolved value is what the UI
+ * shows and what gets saved.
+ */
+@HiltViewModel
+class EventEditViewModel @Inject constructor(
+    private val repository: CalendarRepository,
+    private val prefs: CalendarPrefs,
+    private val settingsPrefs: SettingsPrefs,
+    @IoDispatcher private val io: CoroutineDispatcher,
+) : ViewModel() {
+
+    private val _form = MutableStateFlow<EventForm?>(null)
+    private val _saveState = MutableStateFlow<SaveUiState>(SaveUiState.Idle)
+    // Problems stay hidden until the first save attempt, so a half-filled
+    // form isn't already shouting errors.
+    private val _showProblems = MutableStateFlow(false)
+    // Fields added through the "more fields" picker; folds back on reset().
+    // openForEdit seeds it with the sections that already hold values.
+    private val _revealed = MutableStateFlow<Set<EventFormField>>(emptySet())
+    // Set while the form edits an existing event instead of composing a new one.
+    private val _editTarget = MutableStateFlow<EditTarget?>(null)
+    private val _loadFailed = MutableStateFlow(false)
+    // True once the user has hand-edited the reminders on a new event, which
+    // freezes the auto-applied default: switching calendars no longer overwrites
+    // their choice. Reset with the form.
+    private val _remindersTouched = MutableStateFlow(false)
+
+    /** True when the event to edit couldn't be loaded; the screen closes itself. */
+    val loadFailed: StateFlow<Boolean> = _loadFailed.asStateFlow()
+
+    /**
+     * The event being edited plus everything the form saw at load time.
+     * For recurring events the write scope is chosen at save time; the
+     * tapped occurrence's [beginMillis]/[endMillis] anchor occurrence-level
+     * writes and the conflict re-read. [zone] is pinned at load so a device
+     * timezone change mid-edit can't fake a conflict.
+     */
+    private data class EditTarget(
+        val eventId: Long,
+        val snapshot: EditSnapshot,
+        val beginMillis: Long,
+        val endMillis: Long,
+        val zone: TimeZone,
+    ) {
+        val original: EventForm get() = snapshot.form
+    }
+
+    private data class LocalInputs(
+        val form: EventForm?,
+        val saveState: SaveUiState,
+        val showProblems: Boolean,
+        val revealed: Set<EventFormField>,
+        val editTarget: EditTarget?,
+    )
+
+    private data class ReminderDefaults(
+        val timed: Int?,
+        val allDay: Int?,
+        val timedOverrides: Map<Long, Int?>,
+        val allDayOverrides: Map<Long, Int?>,
+    )
+
+    private data class ExternalInputs(
+        val writable: List<CalendarSource>,
+        val lastUsed: Long?,
+        val defaultFields: Set<EventFormField>,
+        val allowColorOnUnsupported: Boolean,
+    )
+
+    /** Writable calendars — the only valid event targets. */
+    private val writableCalendars: Flow<List<CalendarSource>> = repository.calendars()
+        .map { calendars -> calendars.filter { it.canModifyContents } }
+        .catch { emit(emptyList()) }
+
+    /** The target calendar id, resolved exactly as the form shows it. */
+    private val resolvedCalendarId: Flow<Long?> = combine(
+        _form.map { it?.calendarId },
+        writableCalendars,
+        prefs.lastUsedCalendarId,
+    ) { picked, writable, lastUsed ->
+        picked
+            ?: lastUsed?.takeIf { id -> writable.any { it.id == id } }
+            ?: writable.firstOrNull()?.id
+    }.distinctUntilChanged()
+
+    /** The resolved calendar's published event palette, refetched when it changes. */
+    @OptIn(ExperimentalCoroutinesApi::class)
+    private val colorPalette: Flow<List<EventColorOption>> = resolvedCalendarId
+        .flatMapLatest { id ->
+            flow { emit(id?.let { repository.eventColorPalette(it) }.orEmpty()) }
+        }
+        .flowOn(io)
+
+    val state: StateFlow<EventEditUiState?> = combine(
+        combine(_form, _saveState, _showProblems, _revealed, _editTarget, ::LocalInputs),
+        combine(
+            writableCalendars,
+            prefs.lastUsedCalendarId,
+            settingsPrefs.defaultFormFields,
+            settingsPrefs.allowColorOnUnsupportedCalendars,
+            ::ExternalInputs,
+        ).flowOn(io),
+        colorPalette,
+    ) { local, external, palette ->
+        val form = local.form ?: return@combine null
+        val resolvedId = form.calendarId
+            ?: external.lastUsed?.takeIf { id -> external.writable.any { it.id == id } }
+            ?: external.writable.firstOrNull()?.id
+        val resolved = form.copy(calendarId = resolvedId)
+        val visibleFields = external.defaultFields + local.revealed
+        EventEditUiState(
+            form = resolved,
+            calendars = external.writable,
+            problems = if (local.showProblems) resolved.problems() else emptySet(),
+            saveState = local.saveState,
+            visibleFields = visibleFields,
+            hiddenFields = (EventFormField.entries.toSet() - visibleFields).sorted(),
+            isEditing = local.editTarget != null,
+            // A modified-occurrence exception can't carry its own rule, so
+            // the scope dialog drops "only this event" after a rule change.
+            recurrenceChanged = local.editTarget != null &&
+                resolved.rrule != local.editTarget.original.rrule,
+            colorPalette = palette,
+            allowColorOnUnsupportedCalendars = external.allowColorOnUnsupported,
+        )
+    }
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = null,
+        )
+
+    /**
+     * Initialise a fresh form for a new event on [date]. [startMinutes] (minutes
+     * from midnight) anchors the start when the form is opened by tapping a slot
+     * in the day/week grid; without it the default is the next full hour (today)
+     * or 09:00 (any other day). No-op when a form is already open, so user input
+     * survives configuration changes; [reset] clears it when the screen closes.
+     */
+    fun openNew(date: LocalDate, startMinutes: Int? = null) {
+        if (_form.value != null) return
+        val zone = TimeZone.currentSystemDefault()
+        val now = Clock.System.now()
+        val start = when {
+            startMinutes != null ->
+                LocalDateTime(date, LocalTime(startMinutes / 60, startMinutes % 60))
+            date == now.toLocalDateTime(zone).date -> {
+                // Today: the next full hour (may roll into tomorrow before midnight).
+                val hourMillis = 3_600_000L
+                val rounded = (now.toEpochMilliseconds() / hourMillis + 1) * hourMillis
+                Instant.fromEpochMilliseconds(rounded).toLocalDateTime(zone)
+            }
+            else -> LocalDateTime(date, LocalTime(9, 0))
+        }
+        val end = (start.toInstant(zone) + 1.hours).toLocalDateTime(zone)
+        _form.value = EventForm(calendarId = null, start = start, end = end)
+        applyDefaultReminder()
+    }
+
+    /**
+     * Seed a fresh event from a parsed `.ics` file (the single-event "open into
+     * the create form" path). [form] already carries the file's fields; its
+     * [EventForm.calendarId] is null so the calendar still resolves to the
+     * last-used/first-writable one, and reminders are frozen as touched so the
+     * settings default never overwrites what the file specified. No-op when a
+     * form is already open, so the prefill survives configuration changes.
+     */
+    fun openImported(form: EventForm) {
+        if (_form.value != null || _editTarget.value != null) return
+        _remindersTouched.value = true
+        _revealed.value = form.populatedFields()
+        _form.value = form
+    }
+
+    /**
+     * Prefill a new event's reminders from the settings default — the all-day
+     * default for all-day events, otherwise the resolved calendar's per-calendar
+     * override or the global timed default. No-op while editing an existing event
+     * or once the user has hand-edited the reminders, so the auto-default never
+     * clobbers a manual choice. [calendarId] short-circuits the resolution after a
+     * calendar switch; null resolves it as the form does.
+     */
+    private fun applyDefaultReminder(calendarId: Long? = null) {
+        if (_editTarget.value != null || _remindersTouched.value) return
+        viewModelScope.launch {
+            val defaults = combine(
+                settingsPrefs.defaultReminderMinutes,
+                settingsPrefs.defaultAllDayReminderMinutes,
+                settingsPrefs.perCalendarReminderOverride,
+                settingsPrefs.perCalendarAllDayReminderOverride,
+            ) { timed, allDay, timedOv, allDayOv ->
+                ReminderDefaults(timed, allDay, timedOv, allDayOv)
+            }.first()
+            val targetId = calendarId ?: resolvedCalendarId.first()
+            // Re-check after suspending: bail if the form closed or the user edited.
+            val form = _form.value ?: return@launch
+            if (_editTarget.value != null || _remindersTouched.value) return@launch
+            val default = resolveDefaultReminder(
+                timedGlobal = defaults.timed,
+                allDayGlobal = defaults.allDay,
+                timedOverrides = defaults.timedOverrides,
+                allDayOverrides = defaults.allDayOverrides,
+                calendarId = targetId,
+                isAllDay = form.isAllDay,
+            )
+            val reminders = listOfNotNull(default)
+            _form.value = form.copy(reminders = reminders)
+            // Surface the section so an auto-applied default is visible and
+            // removable, even when Reminders isn't a default-shown field.
+            if (reminders.isNotEmpty()) {
+                _revealed.value = _revealed.value + EventFormField.Reminders
+            }
+        }
+    }
+
+    /**
+     * Load an existing event into the form. [beginMillis]/[endMillis] are the
+     * tapped occurrence's own times, like on the detail screen. No-op while a
+     * form is open, so user edits survive configuration changes.
+     */
+    fun openForEdit(eventId: Long, beginMillis: Long, endMillis: Long) {
+        if (_form.value != null || _editTarget.value != null) return
+        viewModelScope.launch {
+            val detail = try {
+                repository.eventDetail(eventId)
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: Exception) {
+                _loadFailed.value = true
+                return@launch
+            }
+            val zone = TimeZone.currentSystemDefault()
+            val snapshot = detail.toEditSnapshot(beginMillis, endMillis, zone)
+            _editTarget.value = EditTarget(eventId, snapshot, beginMillis, endMillis, zone)
+            // Sections holding data must show even when not in the defaults.
+            _revealed.value = snapshot.form.populatedFields()
+            _form.value = snapshot.form
+        }
+    }
+
+    /** Forget the open form; the next [openNew]/[openForEdit] starts clean. */
+    fun reset() {
+        _form.value = null
+        _saveState.value = SaveUiState.Idle
+        _showProblems.value = false
+        _revealed.value = emptySet()
+        _editTarget.value = null
+        _loadFailed.value = false
+        _remindersTouched.value = false
+    }
+
+    /** Unfold one optional field, picked in the "more fields" dialog. */
+    fun revealField(field: EventFormField) {
+        _revealed.value = _revealed.value + field
+    }
+
+    fun setTitle(value: String) = update { it.copy(title = value) }
+    fun setLocation(value: String) = update { it.copy(location = value) }
+    fun setDescription(value: String) = update { it.copy(description = value) }
+    fun setAllDay(value: Boolean) {
+        update { it.copy(isAllDay = value) }
+        // The default reminder differs for all-day vs timed; re-apply the
+        // type-appropriate default unless the user has hand-edited it (guarded).
+        applyDefaultReminder()
+    }
+
+    /**
+     * Switching calendars drops any chosen colour: a palette key is
+     * account-scoped, and a raw colour may be invalid on the new calendar.
+     * The event falls back to the new calendar's colour until re-picked.
+     */
+    fun setCalendar(id: Long) {
+        update { it.copy(calendarId = id, colorKey = null, color = null) }
+        // A fresh event re-inherits the new calendar's default reminder unless
+        // the user has already hand-edited it (guarded inside).
+        applyDefaultReminder(id)
+    }
+    fun setAvailability(value: Availability) = update { it.copy(availability = value) }
+    fun setAccessLevel(value: AccessLevel) = update { it.copy(accessLevel = value) }
+
+    /** Pick a palette colour (round-trips via its key); [argb] is its swatch. */
+    fun setColorKey(key: String, argb: Int) = update { it.copy(colorKey = key, color = argb) }
+
+    /** Pick a raw colour (local / opted-in calendars), clearing any palette key. */
+    fun setColorRaw(argb: Int) = update { it.copy(colorKey = null, color = argb) }
+
+    /** Clear the colour so the event inherits its calendar's. */
+    fun clearColor() = update { it.copy(colorKey = null, color = null) }
+
+    /** Bare RRULE value from the recurrence picker; null = does not repeat. */
+    fun setRecurrence(rrule: String?) = update { it.copy(rrule = rrule) }
+
+    fun addReminder(minutes: Int) {
+        _remindersTouched.value = true
+        update { it.copy(reminders = (it.reminders + minutes).distinct().sorted()) }
+    }
+
+    fun removeReminder(minutes: Int) {
+        _remindersTouched.value = true
+        update { it.copy(reminders = it.reminders - minutes) }
+    }
+
+    /** Moving the start drags the end along, preserving the duration. */
+    fun setStartDate(date: LocalDate) = moveStart { LocalDateTime(date, it.time) }
+    fun setStartTime(time: LocalTime) = moveStart { LocalDateTime(it.date, time) }
+    fun setEndDate(date: LocalDate) = update { it.copy(end = LocalDateTime(date, it.end.time)) }
+    fun setEndTime(time: LocalTime) = update { it.copy(end = LocalDateTime(it.end.date, time)) }
+
+    /**
+     * Validate and write. Saving a dirty recurring event pauses in
+     * [SaveUiState.AwaitingScope] until the screen answers via
+     * [saveWithScope]; everything else writes directly. Terminal results
+     * land in [saveState].
+     */
+    fun save() {
+        val current = state.value ?: return
+        if (current.saveState == SaveUiState.Saving) return
+        val form = current.form
+        if (form.problems().isNotEmpty()) {
+            _showProblems.value = true
+            return
+        }
+        val target = _editTarget.value
+        if (target != null && form == target.original) {
+            // A pristine form saves as a no-op instead of a write.
+            _saveState.value = SaveUiState.Saved
+            return
+        }
+        if (target != null && target.original.rrule != null) {
+            _saveState.value = SaveUiState.AwaitingScope
+            return
+        }
+        performSave(form, RecurringWriteScope.AllEvents)
+    }
+
+    /** Finish a save parked in [SaveUiState.AwaitingScope]. */
+    fun saveWithScope(scope: RecurringWriteScope) {
+        val current = state.value ?: return
+        if (current.saveState != SaveUiState.AwaitingScope) return
+        performSave(current.form, scope)
+    }
+
+    /** Finish a save parked in [SaveUiState.AwaitingConflict], overwriting. */
+    fun saveOverwriting() {
+        val current = state.value ?: return
+        val parked = current.saveState as? SaveUiState.AwaitingConflict ?: return
+        performSave(current.form, parked.scope, ignoreConflict = true)
+    }
+
+    private fun performSave(
+        form: EventForm,
+        scope: RecurringWriteScope,
+        ignoreConflict: Boolean = false,
+    ) {
+        val target = _editTarget.value
+        viewModelScope.launch {
+            _saveState.value = SaveUiState.Saving
+            // No locking (plan 03, decision 5): right before writing, re-read
+            // the event and compare against what the form loaded. An external
+            // change parks the save in a conflict dialog instead of silently
+            // clobbering the edited fields.
+            if (target != null && !ignoreConflict) {
+                val fresh = try {
+                    repository.eventDetail(target.eventId)
+                        .toEditSnapshot(target.beginMillis, target.endMillis, target.zone)
+                } catch (e: CancellationException) {
+                    throw e
+                } catch (e: NoSuchEventException) {
+                    _saveState.value = SaveUiState.Gone
+                    return@launch
+                } catch (e: Exception) {
+                    // Can't verify — proceed; a real problem fails the write itself.
+                    null
+                }
+                if (fresh != null && fresh != target.snapshot) {
+                    _saveState.value = SaveUiState.AwaitingConflict(scope)
+                    return@launch
+                }
+            }
+            _saveState.value = try {
+                if (target == null) {
+                    repository.createEvent(form)
+                    prefs.setLastUsedCalendarId(requireNotNull(form.calendarId))
+                } else {
+                    when (scope) {
+                        RecurringWriteScope.ThisEvent ->
+                            repository.updateOccurrence(target.eventId, target.beginMillis, form)
+                        RecurringWriteScope.ThisAndFollowing ->
+                            repository.updateEventFromOccurrence(
+                                eventId = target.eventId,
+                                beginMillis = target.beginMillis,
+                                original = target.original,
+                                updated = form,
+                            )
+                        RecurringWriteScope.AllEvents ->
+                            repository.updateEvent(target.eventId, target.original, form)
+                    }
+                }
+                SaveUiState.Saved
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: SecurityException) {
+                SaveUiState.NeedsPermission
+            } catch (e: Exception) {
+                SaveUiState.Failed
+            }
+        }
+    }
+
+    /** Reset [saveState] after the screen handled a terminal result. */
+    fun consumeSaveResult() {
+        _saveState.value = SaveUiState.Idle
+    }
+
+    private fun moveStart(transform: (LocalDateTime) -> LocalDateTime) = update { form ->
+        val zone = TimeZone.currentSystemDefault()
+        val newStart = transform(form.start)
+        val duration = form.end.toInstant(zone) - form.start.toInstant(zone)
+        val newEnd = (newStart.toInstant(zone) + duration).toLocalDateTime(zone)
+        form.copy(start = newStart, end = newEnd)
+    }
+
+    private inline fun update(block: (EventForm) -> EventForm) {
+        _form.value = _form.value?.let(block)
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/filter/CalendarFilterList.kt

@@ -0,0 +1,125 @@
+package de.jeanlucmakiola.calendula.ui.filter
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Checkbox
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.domain.FailureReason
+import de.jeanlucmakiola.calendula.ui.common.CalendarColorChip
+import de.jeanlucmakiola.calendula.ui.common.GroupedRow
+import de.jeanlucmakiola.calendula.ui.common.positionOf
+
+/**
+ * Calendar-visibility filter (M3), rendered inline in the navigation drawer.
+ * Every calendar grouped by account, each with a colour swatch and a visibility
+ * switch; toggling writes straight to DataStore and every calendar view
+ * re-filters live. Three states (Loading / Failure / Success).
+ */
+@Composable
+fun CalendarFilterList(
+    modifier: Modifier = Modifier,
+    viewModel: FilterViewModel = hiltViewModel(),
+) {
+    val state by viewModel.state.collectAsStateWithLifecycle()
+    when (val s = state) {
+        FilterUiState.Loading -> FilterLoading(modifier)
+        is FilterUiState.Failure -> FilterMessage(s.reason, modifier)
+        is FilterUiState.Success -> FilterList(
+            groups = s.groups,
+            onSetVisible = viewModel::setVisible,
+            modifier = modifier,
+        )
+    }
+}
+
+/**
+ * Renders as a plain (non-scrolling) [Column] so it flows inside the drawer's
+ * single scroll container — the whole sidebar scrolls as one. Calendar counts
+ * are small, so a lazy list isn't needed.
+ */
+@Composable
+private fun FilterList(
+    groups: List<AccountGroup>,
+    onSetVisible: (Long, Boolean) -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    Column(modifier = modifier.fillMaxWidth()) {
+        groups.forEach { group ->
+            Text(
+                text = group.account,
+                style = MaterialTheme.typography.labelMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.padding(start = 28.dp, end = 28.dp, top = 12.dp, bottom = 4.dp),
+            )
+            group.calendars.forEachIndexed { index, cal ->
+                GroupedRow(
+                    title = cal.displayName,
+                    position = positionOf(index, group.calendars.size),
+                    minHeight = 56.dp,
+                    leading = { CalendarColorChip(cal.color) },
+                    trailing = {
+                        Checkbox(
+                            checked = cal.visible,
+                            onCheckedChange = { onSetVisible(cal.id, it) },
+                        )
+                    },
+                    onClick = { onSetVisible(cal.id, !cal.visible) },
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun FilterLoading(modifier: Modifier = Modifier) {
+    Column(
+        modifier = modifier.fillMaxWidth(),
+        verticalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        repeat(4) {
+            Box(
+                modifier = Modifier
+                    .padding(horizontal = 28.dp)
+                    .fillMaxWidth()
+                    .height(36.dp)
+                    .background(
+                        MaterialTheme.colorScheme.surfaceContainerHigh,
+                        MaterialTheme.shapes.medium,
+                    ),
+            )
+        }
+    }
+}
+
+@Composable
+private fun FilterMessage(reason: FailureReason, modifier: Modifier = Modifier) {
+    val msg = when (reason) {
+        FailureReason.NoCalendarsConfigured -> R.string.state_failure_no_calendars
+        FailureReason.PermissionRevoked -> R.string.state_failure_permission
+        else -> R.string.state_failure_provider
+    }
+    Text(
+        text = stringResource(msg),
+        style = MaterialTheme.typography.bodyMedium,
+        color = MaterialTheme.colorScheme.onSurfaceVariant,
+        textAlign = TextAlign.Center,
+        modifier = modifier
+            .fillMaxWidth()
+            .padding(horizontal = 28.dp, vertical = 24.dp),
+    )
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/filter/FilterUiState.kt

@@ -0,0 +1,27 @@
+package de.jeanlucmakiola.calendula.ui.filter
+
+import de.jeanlucmakiola.calendula.domain.FailureReason
+
+/**
+ * State for the calendar-filter sheet (M3). The user toggles per-calendar
+ * visibility; the choice is persisted app-side (separate from the system's
+ * VISIBLE flag) and applied to every calendar view.
+ */
+sealed interface FilterUiState {
+    data object Loading : FilterUiState
+    data class Failure(val reason: FailureReason) : FilterUiState
+    data class Success(val groups: List<AccountGroup>) : FilterUiState
+}
+
+/** Calendars grouped under the account that owns them (Nextcloud / Local / …). */
+data class AccountGroup(
+    val account: String,
+    val calendars: List<CalendarRow>,
+)
+
+data class CalendarRow(
+    val id: Long,
+    val displayName: String,
+    val color: Int,
+    val visible: Boolean,
+)

app/src/main/java/de/jeanlucmakiola/calendula/ui/filter/FilterViewModel.kt

@@ -0,0 +1,85 @@
+package de.jeanlucmakiola.calendula.ui.filter
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.FailureReason
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+
+@HiltViewModel
+class FilterViewModel @Inject constructor(
+    private val repository: CalendarRepository,
+    private val prefs: CalendarPrefs,
+    @IoDispatcher private val io: CoroutineDispatcher,
+) : ViewModel() {
+
+    val state: StateFlow<FilterUiState> =
+        combine(
+            repository.calendars(),
+            prefs.hiddenCalendarIds,
+        ) { calendars, hidden ->
+            if (calendars.isEmpty()) {
+                FilterUiState.Failure(FailureReason.NoCalendarsConfigured)
+            } else {
+                FilterUiState.Success(groupByAccount(calendars, hidden))
+            }
+        }
+            .catch { emit(FilterUiState.Failure(FailureReason.ProviderUnavailable)) }
+            .flowOn(io)
+            .stateIn(
+                scope = viewModelScope,
+                started = SharingStarted.WhileSubscribed(5_000L),
+                initialValue = FilterUiState.Loading,
+            )
+
+    /** Show or hide a single calendar; persists the new hidden set. */
+    fun setVisible(calendarId: Long, visible: Boolean) {
+        viewModelScope.launch {
+            val current = prefs.hiddenCalendarIds.first()
+            val next = if (visible) current - calendarId else current + calendarId
+            if (next != current) prefs.setHiddenCalendarIds(next)
+        }
+    }
+}
+
+/**
+ * Group calendars under their owning account, preserving the provider's order
+ * within each group and ordering groups by first appearance. A calendar is
+ * "visible" when its id is *not* in [hidden].
+ */
+internal fun groupByAccount(
+    calendars: List<CalendarSource>,
+    hidden: Set<Long>,
+): List<AccountGroup> =
+    calendars
+        .groupBy { it.accountLabel() }
+        .map { (account, cals) ->
+            AccountGroup(
+                account = account,
+                calendars = cals.map { c ->
+                    CalendarRow(
+                        id = c.id,
+                        displayName = c.displayName,
+                        color = c.color,
+                        visible = c.id !in hidden,
+                    )
+                },
+            )
+        }
+
+/** Account header text: the account name, falling back to its type. */
+private fun CalendarSource.accountLabel(): String =
+    accountName.takeIf { it.isNotBlank() } ?: accountType.takeIf { it.isNotBlank() } ?: displayName

app/src/main/java/de/jeanlucmakiola/calendula/ui/imports/ImportScreen.kt

@@ -0,0 +1,207 @@
+package de.jeanlucmakiola.calendula.ui.imports
+
+import android.net.Uri
+import androidx.activity.compose.BackHandler
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Close
+import androidx.compose.material3.Button
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.material3.TopAppBar
+import androidx.compose.material3.TopAppBarDefaults
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.pluralStringResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.domain.EventForm
+import de.jeanlucmakiola.calendula.domain.ics.IcsParseWarning
+import de.jeanlucmakiola.calendula.ui.common.OptionCard
+
+/**
+ * Handles an opened/received `.ics` file. A single event is handed straight to
+ * the prefilled create form via [onOpenSingle]; several events show a target-
+ * calendar picker and import in bulk (dedup by UID), then a result summary.
+ * Empty/failed files show a short message and close.
+ */
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun ImportScreen(
+    uri: Uri,
+    onClose: () -> Unit,
+    onOpenSingle: (EventForm) -> Unit,
+    viewModel: ImportViewModel = hiltViewModel(),
+) {
+    LaunchedEffect(uri) { viewModel.load(uri) }
+    val state by viewModel.state.collectAsStateWithLifecycle()
+    BackHandler(onBack = onClose)
+
+    // A single event isn't shown here — it opens the create form for review.
+    LaunchedEffect(state) {
+        (state as? ImportUiState.Single)?.let { onOpenSingle(it.form); onClose() }
+    }
+
+    Scaffold(
+        modifier = Modifier.fillMaxSize(),
+        topBar = {
+            TopAppBar(
+                title = { Text(stringResource(R.string.import_title)) },
+                navigationIcon = {
+                    IconButton(onClick = onClose) {
+                        Icon(Icons.Default.Close, contentDescription = stringResource(R.string.event_edit_close))
+                    }
+                },
+                colors = TopAppBarDefaults.topAppBarColors(
+                    containerColor = MaterialTheme.colorScheme.surface,
+                ),
+            )
+        },
+    ) { padding ->
+        Box(Modifier.fillMaxSize().padding(padding)) {
+            when (val s = state) {
+                ImportUiState.Loading,
+                ImportUiState.Importing,
+                is ImportUiState.Single,
+                -> CircularProgressIndicator(Modifier.align(Alignment.Center))
+
+                ImportUiState.Empty -> CenteredMessage(stringResource(R.string.import_empty), onClose)
+                ImportUiState.Failed -> CenteredMessage(stringResource(R.string.import_failed), onClose)
+                is ImportUiState.Many -> ManyContent(s, onImport = viewModel::import)
+                is ImportUiState.Done -> DoneContent(s, onClose)
+            }
+        }
+    }
+}
+
+@Composable
+private fun ManyContent(state: ImportUiState.Many, onImport: (Long) -> Unit) {
+    // No writable calendar to import into — tell the user honestly.
+    if (state.calendars.isEmpty()) {
+        CenteredMessage(stringResource(R.string.import_no_calendar), onClose = null)
+        return
+    }
+    var selected by rememberSaveable { mutableStateOf(state.calendars.first().id) }
+
+    Column(
+        Modifier.fillMaxSize().verticalScroll(rememberScrollState())
+            .padding(horizontal = 16.dp, vertical = 8.dp),
+        verticalArrangement = Arrangement.spacedBy(8.dp),
+    ) {
+        Text(
+            pluralStringResource(R.plurals.import_event_count, state.events.size, state.events.size),
+            style = MaterialTheme.typography.bodyLarge,
+            modifier = Modifier.padding(vertical = 8.dp),
+        )
+        Text(
+            stringResource(R.string.import_target_header),
+            style = MaterialTheme.typography.labelLarge,
+            color = MaterialTheme.colorScheme.primary,
+        )
+        state.calendars.forEach { calendar ->
+            OptionCard(
+                label = calendar.displayName,
+                onClick = { selected = calendar.id },
+                selected = calendar.id == selected,
+                icon = null,
+            )
+        }
+        state.warnings.forEach { WarningText(it) }
+        Button(
+            onClick = { onImport(selected) },
+            modifier = Modifier.fillMaxWidth().padding(top = 8.dp),
+        ) {
+            Text(pluralStringResource(R.plurals.import_action, state.events.size, state.events.size))
+        }
+    }
+}
+
+@Composable
+private fun DoneContent(state: ImportUiState.Done, onClose: () -> Unit) {
+    Column(
+        Modifier.fillMaxSize().padding(24.dp),
+        verticalArrangement = Arrangement.spacedBy(12.dp),
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        Text(
+            stringResource(R.string.import_done_title),
+            style = MaterialTheme.typography.headlineSmall,
+            modifier = Modifier.padding(top = 24.dp),
+        )
+        Text(
+            pluralStringResource(
+                R.plurals.import_done_imported,
+                state.summary.imported,
+                state.summary.imported,
+            ),
+            style = MaterialTheme.typography.bodyLarge,
+        )
+        if (state.summary.skippedDuplicate > 0) {
+            Text(
+                pluralStringResource(
+                    R.plurals.import_done_skipped,
+                    state.summary.skippedDuplicate,
+                    state.summary.skippedDuplicate,
+                ),
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        }
+        Button(onClick = onClose, modifier = Modifier.padding(top = 12.dp)) {
+            Text(stringResource(R.string.import_close))
+        }
+    }
+}
+
+@Composable
+private fun WarningText(warning: IcsParseWarning) {
+    val text = when (warning) {
+        IcsParseWarning.ModifiedOccurrenceSkipped -> stringResource(R.string.import_warning_recurrence)
+        IcsParseWarning.EventWithoutStartSkipped -> stringResource(R.string.import_warning_no_start)
+        IcsParseWarning.AttendeesIgnored -> stringResource(R.string.import_warning_attendees)
+        IcsParseWarning.UnknownTimezone -> stringResource(R.string.import_warning_timezone)
+    }
+    Text(
+        text = text,
+        style = MaterialTheme.typography.bodySmall,
+        color = MaterialTheme.colorScheme.onSurfaceVariant,
+    )
+}
+
+@Composable
+private fun CenteredMessage(message: String, onClose: (() -> Unit)?) {
+    Box(Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+        Column(
+            Modifier.padding(24.dp),
+            verticalArrangement = Arrangement.spacedBy(16.dp),
+            horizontalAlignment = Alignment.CenterHorizontally,
+        ) {
+            Text(message, style = MaterialTheme.typography.bodyLarge)
+            if (onClose != null) {
+                Button(onClick = onClose) { Text(stringResource(R.string.import_close)) }
+            }
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/imports/ImportViewModel.kt

@@ -0,0 +1,105 @@
+package de.jeanlucmakiola.calendula.ui.imports
+
+import android.net.Uri
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.data.ics.IcsImporter
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventForm
+import de.jeanlucmakiola.calendula.domain.ics.IcsImportSummary
+import de.jeanlucmakiola.calendula.domain.ics.IcsParseWarning
+import de.jeanlucmakiola.calendula.domain.ics.IcsParser
+import de.jeanlucmakiola.calendula.domain.ics.ParsedIcsEvent
+import de.jeanlucmakiola.calendula.domain.ics.toEventForm
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import kotlinx.datetime.TimeZone
+import kotlin.coroutines.cancellation.CancellationException
+import javax.inject.Inject
+
+/** What an opened/received `.ics` resolved to. */
+sealed interface ImportUiState {
+    data object Loading : ImportUiState
+    data object Importing : ImportUiState
+
+    /** The file held no importable event (or couldn't be read/parsed as one). */
+    data object Empty : ImportUiState
+    data object Failed : ImportUiState
+
+    /** Exactly one event → review it in the prefilled create form. */
+    data class Single(val form: EventForm, val warnings: Set<IcsParseWarning>) : ImportUiState
+
+    /** Several events → pick a target calendar and bulk-import. */
+    data class Many(
+        val events: List<ParsedIcsEvent>,
+        val warnings: Set<IcsParseWarning>,
+        val calendars: List<CalendarSource>,
+    ) : ImportUiState
+
+    data class Done(val summary: IcsImportSummary) : ImportUiState
+}
+
+/**
+ * Reads an `.ics` [Uri], parses it (pure [IcsParser]) and routes by event count:
+ * one event opens the create form for review, many open the bulk-import picker.
+ * The bulk import dedups by UID in the repository.
+ */
+@HiltViewModel
+class ImportViewModel @Inject constructor(
+    private val repository: CalendarRepository,
+    private val importer: IcsImporter,
+    @IoDispatcher private val io: CoroutineDispatcher,
+) : ViewModel() {
+
+    private val parser = IcsParser()
+    private val _state = MutableStateFlow<ImportUiState>(ImportUiState.Loading)
+    val state: StateFlow<ImportUiState> = _state.asStateFlow()
+    private var started = false
+
+    /** Read + parse [uri] once; subsequent calls (recomposition) are ignored. */
+    fun load(uri: Uri) {
+        if (started) return
+        started = true
+        viewModelScope.launch {
+            val parsed = withContext(io) {
+                importer.readText(uri)?.let(parser::parse)
+            }
+            _state.value = when {
+                parsed == null -> ImportUiState.Failed
+                parsed.events.isEmpty() -> ImportUiState.Empty
+                parsed.events.size == 1 -> ImportUiState.Single(
+                    form = parsed.events.single().toEventForm(TimeZone.currentSystemDefault()),
+                    warnings = parsed.warnings,
+                )
+                else -> ImportUiState.Many(
+                    events = parsed.events,
+                    warnings = parsed.warnings,
+                    calendars = repository.calendars().first().filter { it.canModifyContents },
+                )
+            }
+        }
+    }
+
+    /** Bulk-import the parsed events into [targetCalendarId]; result → [ImportUiState.Done]. */
+    fun import(targetCalendarId: Long) {
+        val many = _state.value as? ImportUiState.Many ?: return
+        viewModelScope.launch {
+            _state.value = ImportUiState.Importing
+            _state.value = try {
+                ImportUiState.Done(repository.importEvents(targetCalendarId, many.events))
+            } catch (e: CancellationException) {
+                throw e
+            } catch (e: Exception) {
+                ImportUiState.Failed
+            }
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/month/MonthScreen.kt

@@ -1,35 +1,30 @@
 package de.jeanlucmakiola.calendula.ui.month
 
 import androidx.compose.animation.AnimatedContent
-import androidx.compose.animation.AnimatedVisibility
-import androidx.compose.animation.core.animateFloatAsState
-import androidx.compose.animation.scaleIn
-import androidx.compose.animation.scaleOut
 import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.gestures.detectHorizontalDragGestures
-import androidx.compose.foundation.interaction.MutableInteractionSource
-import androidx.compose.foundation.interaction.collectIsPressedAsState
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.BoxWithConstraints
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.offset
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Menu
-import androidx.compose.material.icons.filled.Refresh
-import androidx.compose.material3.Card
-import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.DrawerValue
 import androidx.compose.material3.ExperimentalMaterial3Api
-import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
-import androidx.compose.material3.ExtendedFloatingActionButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
@@ -48,7 +43,9 @@ import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.draw.clipToBounds
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.input.nestedscroll.nestedScroll
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.platform.LocalDensity
@@ -57,11 +54,13 @@ import androidx.compose.ui.semantics.contentDescription
 import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.calendula.R
 import de.jeanlucmakiola.calendula.ui.common.CalendarDrawer
+import de.jeanlucmakiola.calendula.ui.common.CalendarFabColumn
 import de.jeanlucmakiola.calendula.ui.common.CalendarFailure
 import de.jeanlucmakiola.calendula.ui.common.CalendarView
 import de.jeanlucmakiola.calendula.ui.common.ViewSwitcherPill
@@ -71,11 +70,12 @@ import de.jeanlucmakiola.calendula.ui.common.rememberCalendarSlideSpec
 import de.jeanlucmakiola.calendula.ui.common.next
 import de.jeanlucmakiola.calendula.ui.common.pastelize
 import kotlinx.coroutines.launch
-import kotlinx.datetime.DateTimeUnit
 import kotlinx.datetime.DayOfWeek
 import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
 import kotlinx.datetime.YearMonth
-import kotlinx.datetime.plus
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Clock
 import java.time.format.TextStyle as JavaTextStyle
 import java.util.Locale
 
@@ -84,11 +84,15 @@ import java.util.Locale
 fun MonthScreen(
     selectedView: CalendarView,
     onSelectView: (CalendarView) -> Unit,
+    onOpenDay: (LocalDate) -> Unit,
+    onOpenSettings: () -> Unit,
+    onCreateEvent: (LocalDate, Int?) -> Unit,
     modifier: Modifier = Modifier,
     viewModel: MonthViewModel = hiltViewModel(),
 ) {
     val state by viewModel.state.collectAsStateWithLifecycle()
     val month by viewModel.month.collectAsStateWithLifecycle()
+    val weekStart by viewModel.weekStart.collectAsStateWithLifecycle()
 
     val scrollBehavior = TopAppBarDefaults.pinnedScrollBehavior()
     val drawerState = rememberDrawerState(DrawerValue.Closed)
@@ -110,10 +114,21 @@ fun MonthScreen(
         slideDir = -1
         viewModel.goToPrev()
     }
+    // Slide toward today: viewing the future → today comes in from the left
+    // (back), viewing the past → from the right (forward).
     val jumpToToday = {
-        slideDir = 0
+        slideDir = when (val s = state) {
+            is MonthUiState.Success ->
+                if (YearMonth(s.today.year, s.today.month) < s.month) -1 else 1
+            else -> 0
+        }
         viewModel.goToToday()
     }
+    // Drawer jump-to-date: slide from the side the target month lies on.
+    val jumpToDate: (LocalDate) -> Unit = { target ->
+        slideDir = if (YearMonth(target.year, target.month) < month) -1 else 1
+        viewModel.goToDate(target)
+    }
 
     ModalNavigationDrawer(
         drawerState = drawerState,
@@ -121,13 +136,20 @@ fun MonthScreen(
         gesturesEnabled = drawerState.isOpen,
         drawerContent = {
             CalendarDrawer(
-                onToday = {
-                    jumpToToday()
+                currentView = selectedView,
+                currentDate = LocalDate(month.year, month.month, 1),
+                onSelectView = { view ->
+                    onSelectView(view)
+                    scope.launch { drawerState.close() }
+                },
+                onJumpToDate = { target ->
+                    jumpToDate(target)
+                    scope.launch { drawerState.close() }
+                },
+                onSettings = {
+                    onOpenSettings()
                     scope.launch { drawerState.close() }
                 },
-                onJumpToDate = { scope.launch { drawerState.close() } /* TODO: open date picker */ },
-                onFilter = { scope.launch { drawerState.close() } /* TODO: open filter sheet */ },
-                onSettings = { scope.launch { drawerState.close() } /* TODO: navigate to settings */ },
             )
         },
     ) {
@@ -143,17 +165,21 @@ fun MonthScreen(
                 )
             },
             floatingActionButton = {
-                AnimatedVisibility(
-                    visible = !isOnCurrentMonth,
-                    enter = scaleIn(),
-                    exit = scaleOut(),
-                ) {
-                    ExtendedFloatingActionButton(
-                        onClick = jumpToToday,
-                        icon = { Icon(Icons.Default.Refresh, contentDescription = null) },
-                        text = { Text(stringResource(R.string.month_today_action)) },
+                CalendarFabColumn(
+                    todayVisible = !isOnCurrentMonth,
+                    todayText = stringResource(R.string.month_today_action),
+                    onToday = jumpToToday,
+                    onCreate = {
+                        // Anchor on today when its month is shown, else the 1st.
+                        val today = Clock.System.now()
+                            .toLocalDateTime(TimeZone.currentSystemDefault()).date
+                        onCreateEvent(
+                            if (isOnCurrentMonth) today
+                            else LocalDate(month.year, month.month, 1),
+                            null,
+                        )
+                    },
                 )
-                }
             },
         ) { innerPadding ->
             Column(
@@ -161,13 +187,14 @@ fun MonthScreen(
                     .padding(innerPadding)
                     .fillMaxSize(),
             ) {
-                WeekdayHeader(weekStart = DayOfWeek.MONDAY)
+                WeekdayHeader(weekStart = weekStart)
                 MonthContent(
                     state = state,
                     slideDir = slideDir,
                     onSwipeNext = goNext,
                     onSwipePrev = goPrev,
                     onRetry = jumpToToday,
+                    onOpenDay = onOpenDay,
                 )
             }
         }
@@ -181,6 +208,7 @@ private fun MonthContent(
     onSwipeNext: () -> Unit,
     onSwipePrev: () -> Unit,
     onRetry: () -> Unit,
+    onOpenDay: (LocalDate) -> Unit,
 ) {
     val density = LocalDensity.current
     val threshold = with(density) { 6.dp.toPx() }
@@ -218,7 +246,10 @@ private fun MonthContent(
         when (s) {
             MonthUiState.Loading -> MonthGridLoading()
             is MonthUiState.Failure -> CalendarFailure(reason = s.reason, onRetry = onRetry)
-            is MonthUiState.Success -> MonthGrid(state = s, weekStart = DayOfWeek.MONDAY)
+            is MonthUiState.Success -> MonthGrid(
+                state = s,
+                onOpenDay = onOpenDay,
+            )
         }
     }
 }
@@ -286,137 +317,279 @@ private fun WeekdayHeader(weekStart: DayOfWeek) {
     }
 }
 
+private val EVENT_ROW_HEIGHT = 20.dp
+private val DAY_NUMBER_HEIGHT = 22.dp
+private val DAY_NUMBER_GAP = 4.dp
+private val CELL_TOP_PADDING = 6.dp
+private val CELL_GAP = 2.dp
+private val CELL_SHAPE = RoundedCornerShape(12.dp)
+private const val MAX_EVENT_ROWS = 3
+
 @Composable
 private fun MonthGrid(
     state: MonthUiState.Success,
-    weekStart: DayOfWeek,
+    onOpenDay: (LocalDate) -> Unit,
 ) {
-    val firstOfMonth = LocalDate(state.month.year, state.month.month, 1)
-    val gridStart = firstOfMonth.startOfGridWeek(weekStart)
-
-    // Show only the weeks the current month actually touches; leading/trailing
-    // days of neighbouring months are left blank rather than rendered.
-    val leadOffset = ((firstOfMonth.dayOfWeek.ordinal - weekStart.ordinal) + 7) % 7
-    val daysInMonth =
-        java.time.YearMonth.of(state.month.year, state.month.month.ordinal + 1).lengthOfMonth()
-    val weeks = (leadOffset + daysInMonth + 6) / 7
-
     Column(
         modifier = Modifier
             .fillMaxSize()
-            .padding(horizontal = 8.dp, vertical = 4.dp),
-        verticalArrangement = Arrangement.spacedBy(8.dp),
+            .padding(horizontal = 4.dp, vertical = 4.dp),
+        verticalArrangement = Arrangement.spacedBy(2.dp),
     ) {
-        repeat(weeks) { row ->
-            Row(
+        state.weeks.forEach { week ->
+            MonthWeekRow(
+                week = week,
+                today = state.today,
+                month = state.month,
+                onOpenDay = onOpenDay,
                 modifier = Modifier
                     .fillMaxWidth()
                     .weight(1f),
-                horizontalArrangement = Arrangement.spacedBy(4.dp),
-            ) {
-                repeat(7) { col ->
-                    val date = gridStart.plus(row * 7 + col, DateTimeUnit.DAY)
-                    val inMonth =
-                        date.month == state.month.month && date.year == state.month.year
-                    if (inMonth) {
-                        DayCard(
-                            date = date,
-                            isToday = date == state.today,
-                            data = state.cells[date],
-                            modifier = Modifier.weight(1f),
             )
-                    } else {
-                        Spacer(Modifier.weight(1f))
-                    }
-                }
-            }
         }
     }
 }
 
-@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+/**
+ * One week of the grid. Bars (all-day / multi-day) are positioned absolutely so
+ * a multi-day event is one connected bar across the columns; single-day timed
+ * events sit beneath them as filled pills in their own cell. The cap is
+ * [MAX_EVENT_ROWS] rows of bars+pills, then a "+N" dot indicator per day.
+ * A transparent per-day layer on top turns a tap into "open that day".
+ */
 @Composable
-private fun DayCard(
-    date: LocalDate,
-    isToday: Boolean,
-    data: DayCellData?,
+private fun MonthWeekRow(
+    week: MonthWeek,
+    today: LocalDate,
+    month: YearMonth,
+    onOpenDay: (LocalDate) -> Unit,
     modifier: Modifier = Modifier,
 ) {
-    val todayPrefix = stringResource(R.string.month_a11y_today_prefix)
-    val cellLabel = buildString {
-        if (isToday) append(todayPrefix).append(", ")
-        append(date.year).append('-')
-        append((date.month.ordinal + 1).toString().padStart(2, '0')).append('-')
-        append(date.day.toString().padStart(2, '0'))
-        data?.let { append(", ").append(it.count).append(" Events") }
-    }
+    val dark = isSystemInDarkTheme()
+    val laneCount = (week.spans.maxOfOrNull { it.lane } ?: -1) + 1
+    val shownLanes = laneCount.coerceAtMost(MAX_EVENT_ROWS)
 
-    // M3 Expressive press feedback: a spatial spring from the active motion
-    // scheme drives a subtle scale, instead of a fixed easing curve.
-    val interactionSource = remember { MutableInteractionSource() }
-    val pressed by interactionSource.collectIsPressedAsState()
-    val scale by animateFloatAsState(
-        targetValue = if (pressed) 0.94f else 1f,
-        animationSpec = MaterialTheme.motionScheme.fastSpatialSpec(),
-        label = "day-card-press",
-    )
+    BoxWithConstraints(modifier) {
+        val colW = maxWidth / 7
 
-    Card(
-        onClick = { /* TODO: open the day view (S3) for this date */ },
-        interactionSource = interactionSource,
-        shape = MaterialTheme.shapes.medium,
-        colors = CardDefaults.cardColors(
-            containerColor = if (isToday) MaterialTheme.colorScheme.primaryContainer
-            else MaterialTheme.colorScheme.surfaceContainerHigh,
-            contentColor = if (isToday) MaterialTheme.colorScheme.onPrimaryContainer
-            else MaterialTheme.colorScheme.onSurface,
+        // Per-day background pills — same surfaceContainer rounded surface the
+        // week/day views use, so the three views share one visual language.
+        // Spanning bars draw on top of these, bridging cells, so they still read
+        // as one continuous event.
+        Row(Modifier.matchParentSize()) {
+            week.days.forEach { d ->
+                val inMonth = d.month == month.month && d.year == month.year
+                Box(
+                    Modifier
+                        .weight(1f)
+                        .fillMaxHeight()
+                        .padding(horizontal = CELL_GAP, vertical = 1.dp)
+                        .background(
+                            color = if (inMonth) MaterialTheme.colorScheme.surfaceContainer
+                            else MaterialTheme.colorScheme.surfaceContainerLow,
+                            shape = CELL_SHAPE,
                         ),
-        modifier = modifier
-            .fillMaxSize()
-            .graphicsLayer {
-                scaleX = scale
-                scaleY = scale
+                )
             }
-            .semantics { contentDescription = cellLabel },
-    ) {
-        Column(
+        }
+
+        Column(Modifier.fillMaxSize().padding(top = CELL_TOP_PADDING)) {
+            Row(Modifier.fillMaxWidth()) {
+                week.days.forEach { d ->
+                    DayNumberCell(
+                        date = d,
+                        isToday = d == today,
+                        inMonth = d.month == month.month && d.year == month.year,
+                        modifier = Modifier.weight(1f),
+                    )
+                }
+            }
+            // Breathing room between the day number (and today's circle) and the
+            // first event row.
+            Spacer(Modifier.height(DAY_NUMBER_GAP))
+            Box(
                 modifier = Modifier
-                .fillMaxSize()
-                .padding(top = 4.dp, bottom = 2.dp),
-            horizontalAlignment = Alignment.CenterHorizontally,
+                    .fillMaxWidth()
+                    .weight(1f)
+                    .clipToBounds(),
+            ) {
+                // Spanning bars on their shared lanes.
+                week.spans.filter { it.lane < shownLanes }.forEach { span ->
+                    val cols = span.endCol - span.startCol + 1
+                    MonthBar(
+                        event = span.event,
+                        dark = dark,
+                        continuesLeft = span.continuesLeft,
+                        continuesRight = span.continuesRight,
+                        modifier = Modifier
+                            .offset(
+                                x = colW * span.startCol,
+                                y = EVENT_ROW_HEIGHT * span.lane,
+                            )
+                            .width(colW * cols)
+                            .height(EVENT_ROW_HEIGHT)
+                            .padding(horizontal = CELL_GAP + 1.dp, vertical = 1.dp),
+                    )
+                }
+                // Single-day timed pills + overflow, per column. Pills fill the
+                // lane slots no bar occupies on THIS day (top-most first), so a
+                // bar-free day isn't pushed down by a multi-day event that only
+                // sits on other days of the week.
+                week.days.forEachIndexed { col, d ->
+                    val timed = week.timedByDay[d].orEmpty()
+                    val occupied = week.spans
+                        .filter { it.lane < shownLanes && col in it.startCol..it.endCol }
+                        .map { it.lane }
+                        .toSet()
+                    val freeSlots = (0 until MAX_EVENT_ROWS).filter { it !in occupied }
+                    val pillsShown = timed.take(freeSlots.size)
+                    pillsShown.forEachIndexed { i, ev ->
+                        MonthBar(
+                            event = ev,
+                            dark = dark,
+                            continuesLeft = false,
+                            continuesRight = false,
+                            modifier = Modifier
+                                .offset(
+                                    x = colW * col,
+                                    y = EVENT_ROW_HEIGHT * freeSlots[i],
+                                )
+                                .width(colW)
+                                .height(EVENT_ROW_HEIGHT)
+                                .padding(horizontal = CELL_GAP + 1.dp, vertical = 1.dp),
+                        )
+                    }
+                    val hidden = (week.countByDay[d] ?: 0) - occupied.size - pillsShown.size
+                    if (hidden > 0) {
+                        val hiddenColors = buildList {
+                            week.spans
+                                .filter { it.lane >= shownLanes && col in it.startCol..it.endCol }
+                                .forEach { add(it.event.color) }
+                            timed.drop(pillsShown.size).forEach { add(it.color) }
+                        }.distinct().take(3)
+                        OverflowDots(
+                            colors = hiddenColors,
+                            extra = hidden - hiddenColors.size,
+                            dark = dark,
+                            modifier = Modifier
+                                .offset(x = colW * col, y = EVENT_ROW_HEIGHT * MAX_EVENT_ROWS)
+                                .width(colW)
+                                .padding(horizontal = 3.dp),
+                        )
+                    }
+                }
+            }
+        }
+
+        // Tap layer: in month view a tap on any day opens that day. Padded and
+        // clipped to the background pill so the ripple matches it.
+        Row(Modifier.matchParentSize()) {
+            week.days.forEach { d ->
+                Box(
+                    Modifier
+                        .weight(1f)
+                        .fillMaxHeight()
+                        .padding(horizontal = CELL_GAP, vertical = 1.dp)
+                        .clip(CELL_SHAPE)
+                        .clickable { onOpenDay(d) },
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun DayNumberCell(
+    date: LocalDate,
+    isToday: Boolean,
+    inMonth: Boolean,
+    modifier: Modifier = Modifier,
+) {
+    Box(
+        modifier = modifier.height(DAY_NUMBER_HEIGHT),
+        contentAlignment = Alignment.Center,
+    ) {
+        if (isToday) {
+            Box(
+                modifier = Modifier
+                    .size(DAY_NUMBER_HEIGHT)
+                    .background(MaterialTheme.colorScheme.primary, CircleShape),
+                contentAlignment = Alignment.Center,
             ) {
                 Text(
                     text = date.day.toString(),
-                style = MaterialTheme.typography.labelLarge,
-                fontWeight = if (isToday) FontWeight.Bold else FontWeight.Normal,
+                    style = MaterialTheme.typography.labelMedium,
+                    fontWeight = FontWeight.Bold,
+                    color = MaterialTheme.colorScheme.onPrimary,
+                )
+            }
+        } else {
+            Text(
+                text = date.day.toString(),
+                style = MaterialTheme.typography.labelMedium,
+                color = if (inMonth) MaterialTheme.colorScheme.onSurface
+                else MaterialTheme.colorScheme.onSurfaceVariant.copy(alpha = 0.4f),
             )
-            Spacer(Modifier.height(2.dp))
-            EventDotRow(data)
         }
     }
 }
 
+/** A filled event pill/bar — pastelized fill, title clipped to one line. */
 @Composable
-private fun EventDotRow(data: DayCellData?) {
-    if (data == null || data.swatches.isEmpty()) {
-        Spacer(Modifier.height(6.dp))
-        return
+private fun MonthBar(
+    event: de.jeanlucmakiola.calendula.domain.EventInstance,
+    dark: Boolean,
+    continuesLeft: Boolean,
+    continuesRight: Boolean,
+    modifier: Modifier = Modifier,
+) {
+    val title = event.title.ifBlank { stringResource(R.string.event_untitled) }
+    val shape = RoundedCornerShape(
+        topStart = if (continuesLeft) 0.dp else 4.dp,
+        bottomStart = if (continuesLeft) 0.dp else 4.dp,
+        topEnd = if (continuesRight) 0.dp else 4.dp,
+        bottomEnd = if (continuesRight) 0.dp else 4.dp,
+    )
+    Box(
+        modifier = modifier
+            .background(pastelize(event.color, dark), shape)
+            .padding(horizontal = 4.dp)
+            .semantics { contentDescription = title },
+        contentAlignment = Alignment.CenterStart,
+    ) {
+        Text(
+            text = title,
+            style = MaterialTheme.typography.labelSmall,
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis,
+            color = Color.Black.copy(alpha = 0.8f),
+        )
     }
-    val dark = isSystemInDarkTheme()
+}
+
+/** Overflow row: a dot per hidden event (up to three) plus "+N" for the rest. */
+@Composable
+private fun OverflowDots(
+    colors: List<Int>,
+    extra: Int,
+    dark: Boolean,
+    modifier: Modifier = Modifier,
+) {
     Row(
+        modifier = modifier.height(EVENT_ROW_HEIGHT),
         horizontalArrangement = Arrangement.spacedBy(2.dp),
         verticalAlignment = Alignment.CenterVertically,
     ) {
-        data.swatches.forEach { argb ->
+        colors.forEach { argb ->
             Box(
                 modifier = Modifier
                     .size(6.dp)
                     .background(pastelize(argb, dark), CircleShape),
             )
         }
-        if (data.count > data.swatches.size) {
+        if (extra > 0) {
             Text(
-                text = "+${data.count - data.swatches.size}",
+                text = "+$extra",
                 style = MaterialTheme.typography.labelSmall,
                 color = MaterialTheme.colorScheme.onSurfaceVariant,
             )

app/src/main/java/de/jeanlucmakiola/calendula/ui/month/MonthUiState.kt

@@ -1,20 +1,40 @@
 package de.jeanlucmakiola.calendula.ui.month
 
+import de.jeanlucmakiola.calendula.domain.EventInstance
 import de.jeanlucmakiola.calendula.domain.FailureReason
 import kotlinx.datetime.LocalDate
 import kotlinx.datetime.YearMonth
 
 /**
- * Per-day aggregation surfaced to the month grid. We only need
- *   - the total event count (drives the optional "+N" indicator), and
- *   - up to three calendar colors for the dot row.
- *
- * The day cell never holds full event objects — the detail sheet pulls those
- * lazily.
+ * An all-day or multi-day event laid out as one connected horizontal bar across
+ * a week row, [startCol]..[endCol], stacked on [lane] so overlapping spans don't
+ * collide. Mirrors the week view's [de.jeanlucmakiola.calendula.ui.week.AllDaySpan]
+ * but adds clip flags so a bar that started in an earlier week (or runs into a
+ * later one) drops its rounded cap on that side.
  */
-data class DayCellData(
-    val count: Int,
-    val swatches: List<Int>,
+data class MonthSpan(
+    val event: EventInstance,
+    val startCol: Int,
+    val endCol: Int,
+    val lane: Int,
+    val continuesLeft: Boolean,
+    val continuesRight: Boolean,
+)
+
+/**
+ * One week row of the grid with its events resolved for rendering.
+ *
+ *  - [spans] are the all-day/multi-day bars, lanes already assigned for the row.
+ *  - [timedByDay] holds the single-day timed events per date, sorted by start;
+ *    these render as filled pills beneath the bar lanes in their own cell.
+ *  - [countByDay] is the total number of events touching each date (bars + pills),
+ *    so the cell can compute the "+N" overflow once the visible-row cap is known.
+ */
+data class MonthWeek(
+    val days: List<LocalDate>,
+    val spans: List<MonthSpan>,
+    val timedByDay: Map<LocalDate, List<EventInstance>>,
+    val countByDay: Map<LocalDate, Int>,
 )
 
 sealed interface MonthUiState {
@@ -23,6 +43,6 @@ sealed interface MonthUiState {
     data class Success(
         val month: YearMonth,
         val today: LocalDate,
-        val cells: Map<LocalDate, DayCellData>,
+        val weeks: List<MonthWeek>,
     ) : MonthUiState
 }

app/src/main/java/de/jeanlucmakiola/calendula/ui/month/MonthViewModel.kt

@@ -5,9 +5,13 @@ import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
 import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.data.prefs.resolveFirstDay
 import de.jeanlucmakiola.calendula.domain.CalendarSource
 import de.jeanlucmakiola.calendula.domain.EventInstance
 import de.jeanlucmakiola.calendula.domain.FailureReason
+import de.jeanlucmakiola.calendula.ui.week.coversDay
+import de.jeanlucmakiola.calendula.ui.week.layoutAllDay
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -17,6 +21,7 @@ import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.datetime.DateTimeUnit
 import kotlinx.datetime.DayOfWeek
@@ -29,6 +34,7 @@ import kotlinx.datetime.minus
 import kotlinx.datetime.plus
 import kotlinx.datetime.toInstant
 import kotlinx.datetime.toLocalDateTime
+import java.util.Locale
 import kotlin.time.Clock
 import kotlin.time.Instant
 import javax.inject.Inject
@@ -37,13 +43,21 @@ import javax.inject.Inject
 @HiltViewModel
 class MonthViewModel @Inject constructor(
     private val repository: CalendarRepository,
+    settingsPrefs: SettingsPrefs,
     @IoDispatcher private val io: CoroutineDispatcher,
 ) : ViewModel() {
 
     private val zone = TimeZone.currentSystemDefault()
+    private val locale: Locale = Locale.getDefault()
 
-    // V1: week starts Monday. DataStore-driven preference comes with Settings.
-    private val weekStart: DayOfWeek = DayOfWeek.MONDAY
+    /** First day of the week, from the Settings preference (AUTO → locale). */
+    val weekStart: StateFlow<DayOfWeek> = settingsPrefs.weekStart
+        .map { it.resolveFirstDay(locale) }
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = DayOfWeek.MONDAY,
+        )
 
     private val todayDate: LocalDate
         get() = Clock.System.now().toLocalDateTime(zone).date
@@ -51,14 +65,15 @@ class MonthViewModel @Inject constructor(
     private val _month = MutableStateFlow(YearMonth(todayDate.year, todayDate.month))
     val month: StateFlow<YearMonth> = _month
 
-    val state: StateFlow<MonthUiState> = _month
-        .flatMapLatest { ym ->
-            val range = monthGridRange(ym, weekStart, zone)
+    val state: StateFlow<MonthUiState> =
+        combine(_month, weekStart) { ym, ws -> ym to ws }
+            .flatMapLatest { (ym, ws) ->
+                val range = monthGridRange(ym, ws, zone)
                 combine(
                     repository.calendars(),
                     repository.instances(range),
                 ) { calendars, instances ->
-                buildState(ym, calendars, instances)
+                    buildState(ym, ws, calendars, instances)
                 }
             }
             .catch { emit(MonthUiState.Failure(FailureReason.ProviderUnavailable)) }
@@ -81,25 +96,73 @@ class MonthViewModel @Inject constructor(
         _month.value = YearMonth(todayDate.year, todayDate.month)
     }
 
+    /** Jump to the month containing [date] (drawer jump-to-date). */
+    fun goToDate(date: LocalDate) {
+        _month.value = YearMonth(date.year, date.month)
+    }
+
     private fun buildState(
         ym: YearMonth,
+        weekStart: DayOfWeek,
         calendars: List<CalendarSource>,
         instances: List<EventInstance>,
     ): MonthUiState {
         if (calendars.isEmpty()) {
             return MonthUiState.Failure(FailureReason.NoCalendarsConfigured)
         }
-        val byDay = instances.groupBy { it.start.toLocalDateTime(zone).date }
-            .mapValues { (_, evs) ->
-                DayCellData(
-                    count = evs.size,
-                    swatches = evs.map { it.color }.distinct().take(3),
-                )
-            }
         return MonthUiState.Success(
             month = ym,
             today = todayDate,
-            cells = byDay,
+            weeks = layoutMonthWeeks(ym, weekStart, instances, zone),
+        )
+    }
+}
+
+/**
+ * Split the month grid into week rows and resolve each row's events. An event is
+ * a spanning bar when it's all-day or touches more than one of the row's days;
+ * everything else is a single-day timed pill. Bars get lanes from the shared
+ * [layoutAllDay] so a multi-day event stays on one row across the week.
+ *
+ * Shared by the Month screen and the month home-screen widget so both lay out
+ * spans, lanes and per-day counts identically.
+ */
+internal fun layoutMonthWeeks(
+    ym: YearMonth,
+    weekStart: DayOfWeek,
+    instances: List<EventInstance>,
+    zone: TimeZone,
+): List<MonthWeek> {
+    val firstOfMonth = LocalDate(ym.year, ym.month, 1)
+    val gridStart = firstOfMonth.startOfGridWeek(weekStart)
+    val leadOffset = ((firstOfMonth.dayOfWeek.ordinal - weekStart.ordinal) + 7) % 7
+    val daysInMonth =
+        java.time.YearMonth.of(ym.year, ym.month.ordinal + 1).lengthOfMonth()
+    val weekCount = (leadOffset + daysInMonth + 6) / 7
+
+    return (0 until weekCount).map { row ->
+        val days = (0 until 7).map { gridStart.plus(row * 7 + it, DateTimeUnit.DAY) }
+        val weekEvents = instances.filter { ev -> days.any { ev.coversDay(it, zone) } }
+        val (bars, singles) = weekEvents.partition { ev ->
+            ev.isAllDay || days.count { ev.coversDay(it, zone) } > 1
+        }
+        val spans = layoutAllDay(bars, days, zone).map { s ->
+            MonthSpan(
+                event = s.event,
+                startCol = s.startCol,
+                endCol = s.endCol,
+                lane = s.lane,
+                continuesLeft = s.event.coversDay(days.first().minus(1, DateTimeUnit.DAY), zone),
+                continuesRight = s.event.coversDay(days.last().plus(1, DateTimeUnit.DAY), zone),
+            )
+        }
+        MonthWeek(
+            days = days,
+            spans = spans,
+            timedByDay = days.associateWith { d ->
+                singles.filter { it.coversDay(d, zone) }.sortedBy { it.start }
+            },
+            countByDay = days.associateWith { d -> weekEvents.count { it.coversDay(d, zone) } },
         )
     }
 }

app/src/main/java/de/jeanlucmakiola/calendula/ui/permission/OnboardingScaffold.kt

@@ -0,0 +1,163 @@
+package de.jeanlucmakiola.calendula.ui.permission
+
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.navigationBarsPadding
+import androidx.compose.foundation.layout.offset
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Lock
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.res.colorResource
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import de.jeanlucmakiola.calendula.R
+
+/** MD3 8dp spacing scale shared by the onboarding screens. */
+internal object OnboardingSpace {
+    val xs = 8.dp
+    val sm = 16.dp
+    val md = 24.dp
+    val lg = 32.dp
+    val xl = 48.dp
+}
+
+/**
+ * Shared onboarding shell (calendar grant, reminder step): a scrollable,
+ * centred hero + body with the call(s) to action pinned to the bottom (clear
+ * of the navigation bar). The content slot is centred horizontally; benefit
+ * rows fill the width so their own content left-aligns.
+ */
+@Composable
+internal fun OnboardingScaffold(
+    hero: @Composable () -> Unit,
+    actions: @Composable ColumnScope.() -> Unit,
+    modifier: Modifier = Modifier,
+    body: @Composable ColumnScope.() -> Unit,
+) {
+    Scaffold(
+        modifier = modifier,
+        containerColor = MaterialTheme.colorScheme.surface,
+        bottomBar = {
+            Column(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .navigationBarsPadding()
+                    .padding(horizontal = OnboardingSpace.md, vertical = OnboardingSpace.sm),
+                horizontalAlignment = Alignment.CenterHorizontally,
+                verticalArrangement = Arrangement.spacedBy(4.dp),
+                content = actions,
+            )
+        },
+    ) { innerPadding ->
+        Column(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(innerPadding)
+                .verticalScroll(rememberScrollState())
+                .padding(horizontal = OnboardingSpace.md),
+            horizontalAlignment = Alignment.CenterHorizontally,
+        ) {
+            Spacer(Modifier.height(OnboardingSpace.xl))
+            hero()
+            Spacer(Modifier.height(OnboardingSpace.lg))
+            body()
+            Spacer(Modifier.height(OnboardingSpace.md))
+        }
+    }
+}
+
+/** The app's adaptive launcher mark, reconstructed as a large branded squircle. */
+@Composable
+internal fun BrandHero(denied: Boolean) {
+    Box(contentAlignment = Alignment.Center) {
+        Box(
+            modifier = Modifier
+                .size(128.dp)
+                .clip(RoundedCornerShape(34.dp))
+                .background(colorResource(R.color.ic_launcher_background)),
+        ) {
+            Image(
+                painter = painterResource(R.drawable.ic_launcher_foreground),
+                contentDescription = stringResource(R.string.app_name),
+                modifier = Modifier.fillMaxSize(),
+            )
+        }
+        if (denied) {
+            // A small lock badge sits over the corner to signal "blocked".
+            Box(
+                modifier = Modifier
+                    .align(Alignment.BottomEnd)
+                    .offset(x = 10.dp, y = 10.dp)
+                    .size(44.dp)
+                    .clip(CircleShape)
+                    .background(MaterialTheme.colorScheme.errorContainer),
+                contentAlignment = Alignment.Center,
+            ) {
+                Icon(
+                    imageVector = Icons.Filled.Lock,
+                    contentDescription = null,
+                    tint = MaterialTheme.colorScheme.onErrorContainer,
+                    modifier = Modifier.size(24.dp),
+                )
+            }
+        }
+    }
+}
+
+/** One trust point: a tonal icon chip on the left, title + supporting text right. */
+@Composable
+internal fun BenefitRow(icon: ImageVector, title: String, body: String) {
+    Row(
+        modifier = Modifier.fillMaxWidth(),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Box(
+            modifier = Modifier
+                .size(44.dp)
+                .clip(CircleShape)
+                .background(MaterialTheme.colorScheme.secondaryContainer),
+            contentAlignment = Alignment.Center,
+        ) {
+            Icon(
+                imageVector = icon,
+                contentDescription = null,
+                tint = MaterialTheme.colorScheme.onSecondaryContainer,
+                modifier = Modifier.size(22.dp),
+            )
+        }
+        Spacer(Modifier.width(OnboardingSpace.sm))
+        Column(modifier = Modifier.weight(1f)) {
+            Text(text = title, style = MaterialTheme.typography.titleMedium)
+            Text(
+                text = body,
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/permission/PermissionScreen.kt

@@ -7,15 +7,24 @@ import android.provider.Settings
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
-import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.ArrowForward
+import androidx.compose.material.icons.filled.CalendarMonth
+import androidx.compose.material.icons.filled.Lock
+import androidx.compose.material.icons.filled.VisibilityOff
 import androidx.compose.material3.Button
+import androidx.compose.material3.ButtonDefaults
+import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.OutlinedButton
 import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
@@ -23,11 +32,18 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.calendula.R
 
+private val CALENDAR_PERMISSIONS = arrayOf(
+    Manifest.permission.READ_CALENDAR,
+    Manifest.permission.WRITE_CALENDAR,
+)
+
 @Composable
 fun PermissionScreen(
     onGranted: () -> Unit,
@@ -36,10 +52,17 @@ fun PermissionScreen(
 ) {
     val state by viewModel.state.collectAsStateWithLifecycle()
 
+    // READ and WRITE are requested together (one system dialog — same
+    // permission group), but only READ gates the app: declining write keeps
+    // Calendula usable read-only.
     val launcher = rememberLauncherForActivityResult(
-        contract = ActivityResultContracts.RequestPermission(),
-    ) { granted ->
-        if (granted) viewModel.onGranted() else viewModel.onDenied()
+        contract = ActivityResultContracts.RequestMultiplePermissions(),
+    ) { results ->
+        if (results[Manifest.permission.READ_CALENDAR] == true) {
+            viewModel.onGranted()
+        } else {
+            viewModel.onDenied()
+        }
     }
 
     LaunchedEffect(state) {
@@ -48,13 +71,13 @@ fun PermissionScreen(
 
     when (state) {
         is PermissionUiState.Rationale -> RationaleContent(
-            onRequest = { launcher.launch(Manifest.permission.READ_CALENDAR) },
+            onRequest = { launcher.launch(CALENDAR_PERMISSIONS) },
             modifier = modifier,
         )
         is PermissionUiState.Denied -> DeniedContent(
             onRetry = {
                 viewModel.onRetry()
-                launcher.launch(Manifest.permission.READ_CALENDAR)
+                launcher.launch(CALENDAR_PERMISSIONS)
             },
             modifier = modifier,
         )
@@ -69,24 +92,68 @@ private fun RationaleContent(
     onRequest: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
-    Column(
-        modifier = modifier.fillMaxSize().padding(24.dp),
-        verticalArrangement = Arrangement.Center,
-        horizontalAlignment = Alignment.CenterHorizontally,
+    OnboardingScaffold(
+        modifier = modifier,
+        hero = { BrandHero(denied = false) },
+        actions = {
+            Button(
+                onClick = onRequest,
+                modifier = Modifier.fillMaxWidth().height(56.dp),
+                contentPadding = ButtonDefaults.ButtonWithIconContentPadding,
             ) {
+                Text(
+                    text = stringResource(R.string.permission_request_button),
+                    style = MaterialTheme.typography.titleMedium,
+                )
+                Spacer(Modifier.width(OnboardingSpace.xs))
+                Icon(
+                    imageVector = Icons.AutoMirrored.Filled.ArrowForward,
+                    contentDescription = null,
+                    modifier = Modifier.size(20.dp),
+                )
+            }
+            PrivacyFootnote()
+        },
+    ) {
+        Text(
+            text = stringResource(R.string.app_name).uppercase(),
+            style = MaterialTheme.typography.labelLarge,
+            color = MaterialTheme.colorScheme.primary,
+            letterSpacing = 2.sp,
+        )
+        Spacer(Modifier.height(OnboardingSpace.xs))
         Text(
             text = stringResource(R.string.permission_rationale_title),
             style = MaterialTheme.typography.headlineMedium,
+            textAlign = TextAlign.Center,
         )
-        Spacer(Modifier.height(16.dp))
+        Spacer(Modifier.height(12.dp))
         Text(
             text = stringResource(R.string.permission_rationale_body),
             style = MaterialTheme.typography.bodyLarge,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            textAlign = TextAlign.Center,
+        )
+
+        Spacer(Modifier.height(OnboardingSpace.xl))
+
+        BenefitRow(
+            icon = Icons.Filled.Lock,
+            title = stringResource(R.string.permission_benefit_private_title),
+            body = stringResource(R.string.permission_benefit_private_body),
+        )
+        Spacer(Modifier.height(OnboardingSpace.sm))
+        BenefitRow(
+            icon = Icons.Filled.CalendarMonth,
+            title = stringResource(R.string.permission_benefit_sync_title),
+            body = stringResource(R.string.permission_benefit_sync_body),
+        )
+        Spacer(Modifier.height(OnboardingSpace.sm))
+        BenefitRow(
+            icon = Icons.Filled.VisibilityOff,
+            title = stringResource(R.string.permission_benefit_privacy_title),
+            body = stringResource(R.string.permission_benefit_privacy_body),
         )
-        Spacer(Modifier.height(32.dp))
-        Button(onClick = onRequest) {
-            Text(stringResource(R.string.permission_request_button))
-        }
     }
 }
 
@@ -96,26 +163,11 @@ private fun DeniedContent(
     modifier: Modifier = Modifier,
 ) {
     val context = LocalContext.current
-    Column(
-        modifier = modifier.fillMaxSize().padding(24.dp),
-        verticalArrangement = Arrangement.Center,
-        horizontalAlignment = Alignment.CenterHorizontally,
-    ) {
-        Text(
-            text = stringResource(R.string.permission_denied_title),
-            style = MaterialTheme.typography.headlineMedium,
-        )
-        Spacer(Modifier.height(16.dp))
-        Text(
-            text = stringResource(R.string.permission_denied_body),
-            style = MaterialTheme.typography.bodyLarge,
-        )
-        Spacer(Modifier.height(32.dp))
-        Button(onClick = onRetry) {
-            Text(stringResource(R.string.permission_retry_button))
-        }
-        Spacer(Modifier.height(12.dp))
-        OutlinedButton(
+    OnboardingScaffold(
+        modifier = modifier,
+        hero = { BrandHero(denied = true) },
+        actions = {
+            Button(
                 onClick = {
                     val intent = Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS).apply {
                         data = Uri.fromParts("package", context.packageName, null)
@@ -123,8 +175,54 @@ private fun DeniedContent(
                     }
                     context.startActivity(intent)
                 },
+                modifier = Modifier.fillMaxWidth().height(56.dp),
             ) {
-            Text(stringResource(R.string.permission_open_settings_button))
+                Text(
+                    text = stringResource(R.string.permission_open_settings_button),
+                    style = MaterialTheme.typography.titleMedium,
+                )
+            }
+            TextButton(
+                onClick = onRetry,
+                modifier = Modifier.fillMaxWidth(),
+            ) {
+                Text(stringResource(R.string.permission_retry_button))
+            }
+        },
+    ) {
+        Text(
+            text = stringResource(R.string.permission_denied_title),
+            style = MaterialTheme.typography.headlineMedium,
+            textAlign = TextAlign.Center,
+        )
+        Spacer(Modifier.height(12.dp))
+        Text(
+            text = stringResource(R.string.permission_denied_body),
+            style = MaterialTheme.typography.bodyLarge,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            textAlign = TextAlign.Center,
+        )
     }
 }
+
+@Composable
+private fun PrivacyFootnote() {
+    Row(
+        modifier = Modifier.fillMaxWidth().padding(top = 4.dp),
+        horizontalArrangement = Arrangement.Center,
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Icon(
+            imageVector = Icons.Filled.Lock,
+            contentDescription = null,
+            tint = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.size(14.dp),
+        )
+        Spacer(Modifier.width(6.dp))
+        Text(
+            text = stringResource(R.string.permission_privacy_footnote),
+            style = MaterialTheme.typography.labelMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+        )
+    }
 }

app/src/main/java/de/jeanlucmakiola/calendula/ui/permission/ReminderOnboardingScreen.kt

@@ -0,0 +1,138 @@
+package de.jeanlucmakiola.calendula.ui.permission
+
+import android.Manifest
+import android.os.Build
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.NotificationsActive
+import androidx.compose.material.icons.filled.ContentCopy
+import androidx.compose.material.icons.filled.Tune
+import androidx.compose.material3.Button
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import de.jeanlucmakiola.calendula.R
+
+/**
+ * One-time onboarding step after the calendar grant (v1.4): explains that
+ * Calendula delivers reminder notifications itself, warns about duplicates
+ * when a second calendar app has notifications on, and requests
+ * `POST_NOTIFICATIONS` (a system dialog on API 33+ only; minSdk is 29).
+ *
+ * Reminders default ON: [onFinished] gets true from the primary action even
+ * if the system dialog is declined — the OS permission is the real gate, and
+ * the Settings toggle re-requests it. "Not now" turns the in-app toggle off.
+ */
+@Composable
+fun ReminderOnboardingScreen(
+    onFinished: (remindersEnabled: Boolean) -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val launcher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.RequestPermission(),
+    ) { onFinished(true) }
+
+    OnboardingScaffold(
+        modifier = modifier,
+        hero = { BellHero() },
+        actions = {
+            Button(
+                onClick = {
+                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+                        launcher.launch(Manifest.permission.POST_NOTIFICATIONS)
+                    } else {
+                        onFinished(true)
+                    }
+                },
+                modifier = Modifier.fillMaxWidth().height(56.dp),
+            ) {
+                Text(
+                    text = stringResource(R.string.reminder_onboarding_enable_button),
+                    style = MaterialTheme.typography.titleMedium,
+                )
+            }
+            TextButton(
+                onClick = { onFinished(false) },
+                modifier = Modifier.fillMaxWidth(),
+            ) {
+                Text(stringResource(R.string.reminder_onboarding_skip_button))
+            }
+        },
+    ) {
+        Text(
+            text = stringResource(R.string.app_name).uppercase(),
+            style = MaterialTheme.typography.labelLarge,
+            color = MaterialTheme.colorScheme.primary,
+            letterSpacing = 2.sp,
+        )
+        Spacer(Modifier.height(OnboardingSpace.xs))
+        Text(
+            text = stringResource(R.string.reminder_onboarding_title),
+            style = MaterialTheme.typography.headlineMedium,
+            textAlign = TextAlign.Center,
+        )
+        Spacer(Modifier.height(12.dp))
+        Text(
+            text = stringResource(R.string.reminder_onboarding_body),
+            style = MaterialTheme.typography.bodyLarge,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            textAlign = TextAlign.Center,
+        )
+
+        Spacer(Modifier.height(OnboardingSpace.xl))
+
+        BenefitRow(
+            icon = Icons.Filled.NotificationsActive,
+            title = stringResource(R.string.reminder_benefit_delivery_title),
+            body = stringResource(R.string.reminder_benefit_delivery_body),
+        )
+        Spacer(Modifier.height(OnboardingSpace.sm))
+        BenefitRow(
+            icon = Icons.Filled.ContentCopy,
+            title = stringResource(R.string.reminder_benefit_duplicates_title),
+            body = stringResource(R.string.reminder_benefit_duplicates_body),
+        )
+        Spacer(Modifier.height(OnboardingSpace.sm))
+        BenefitRow(
+            icon = Icons.Filled.Tune,
+            title = stringResource(R.string.reminder_benefit_reversible_title),
+            body = stringResource(R.string.reminder_benefit_reversible_body),
+        )
+    }
+}
+
+/** A bell in the brand squircle — same silhouette as the permission hero. */
+@Composable
+private fun BellHero() {
+    Box(
+        modifier = Modifier
+            .size(128.dp)
+            .clip(RoundedCornerShape(34.dp))
+            .background(MaterialTheme.colorScheme.primaryContainer),
+        contentAlignment = Alignment.Center,
+    ) {
+        Icon(
+            imageVector = Icons.Filled.NotificationsActive,
+            contentDescription = null,
+            tint = MaterialTheme.colorScheme.onPrimaryContainer,
+            modifier = Modifier.size(56.dp),
+        )
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/permission/ReminderOnboardingViewModel.kt

@@ -0,0 +1,39 @@
+package de.jeanlucmakiola.calendula.ui.permission
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+
+/**
+ * Gates the one-time reminder onboarding step (v1.4) shown after the calendar
+ * grant. [onboardingDone] is null until DataStore's first emission so the
+ * step neither flashes for users who completed it nor gets skipped.
+ */
+@HiltViewModel
+class ReminderOnboardingViewModel @Inject constructor(
+    private val prefs: SettingsPrefs,
+) : ViewModel() {
+
+    val onboardingDone: StateFlow<Boolean?> = prefs.reminderOnboardingDone
+        .map { done -> done as Boolean? }
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = null,
+        )
+
+    /** Close the step, recording whether reminder notifications stay on. */
+    fun finish(remindersEnabled: Boolean) {
+        viewModelScope.launch {
+            prefs.setRemindersEnabled(remindersEnabled)
+            prefs.setReminderOnboardingDone()
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/AppLanguage.kt

@@ -0,0 +1,78 @@
+package de.jeanlucmakiola.calendula.ui.settings
+
+import android.content.Context
+import androidx.appcompat.app.AppCompatDelegate
+import androidx.core.os.LocaleListCompat
+import de.jeanlucmakiola.calendula.R
+import org.xmlpull.v1.XmlPullParser
+import java.util.Locale
+
+private const val ANDROID_NS = "http://schemas.android.com/apk/res/android"
+
+/**
+ * Per-app language via AppCompatDelegate, driven by res/xml/locales_config.xml.
+ *
+ * That file is the single source of truth for which languages we ship: dropping
+ * in a values-<tag> translation and adding a matching `<locale>` entry makes the
+ * language show up here and in the system per-app-language settings, with no
+ * other code change. The system-default choice is represented as `null`.
+ *
+ * On API 33+ this delegates to the platform per-app-languages API; below that
+ * the appcompat backport persists the choice itself (manifest `autoStoreLocales`
+ * service), so we don't mirror it in DataStore. Setting a locale recreates the
+ * activity, which re-reads the current value for the picker.
+ */
+object AppLanguage {
+
+    /**
+     * The BCP-47 tags the app ships translations for, in declaration order, as
+     * listed in locales_config.xml. Returns whatever could be parsed; a missing
+     * or malformed config yields an empty list (the picker then offers only the
+     * system-default entry rather than crashing).
+     */
+    fun supportedTags(context: Context): List<String> {
+        val tags = mutableListOf<String>()
+        val parser = context.resources.getXml(R.xml.locales_config)
+        try {
+            var event = parser.eventType
+            while (event != XmlPullParser.END_DOCUMENT) {
+                if (event == XmlPullParser.START_TAG && parser.name == "locale") {
+                    parser.getAttributeValue(ANDROID_NS, "name")?.let(tags::add)
+                }
+                event = parser.next()
+            }
+        } catch (_: Exception) {
+            // Fall back to whatever was parsed before the failure.
+        } finally {
+            parser.close()
+        }
+        return tags
+    }
+
+    /** The applied app language as a BCP-47 tag, or `null` when following the system. */
+    fun currentTag(): String? {
+        val locales = AppCompatDelegate.getApplicationLocales()
+        return if (locales.isEmpty) null else locales[0]?.toLanguageTag()
+    }
+
+    /** Apply a BCP-47 tag, or `null` to follow the system languages. */
+    fun apply(tag: String?) {
+        val locales = if (tag == null) {
+            LocaleListCompat.getEmptyLocaleList()
+        } else {
+            LocaleListCompat.forLanguageTags(tag)
+        }
+        AppCompatDelegate.setApplicationLocales(locales)
+    }
+
+    /**
+     * The autonym for a tag — the language's own name in its own script, e.g.
+     * "Deutsch", "English", "Français" — so users find their language regardless
+     * of the current UI language. Capitalised per the language's own rules.
+     */
+    fun displayName(tag: String): String {
+        val locale = Locale.forLanguageTag(tag)
+        return locale.getDisplayName(locale)
+            .replaceFirstChar { if (it.isLowerCase()) it.titlecase(locale) else it.toString() }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/SettingsScreen.kt

@@ -0,0 +1,856 @@
+package de.jeanlucmakiola.calendula.ui.settings
+
+import android.Manifest
+import android.content.Context
+import android.content.Intent
+import android.content.pm.PackageManager
+import android.os.Build
+import android.os.PowerManager
+import android.provider.Settings
+import android.text.format.DateFormat
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.slideInHorizontally
+import androidx.compose.animation.slideOutHorizontally
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.requiredSize
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.CalendarMonth
+import androidx.compose.material.icons.filled.Check
+import androidx.compose.material.icons.filled.ExpandLess
+import androidx.compose.material.icons.filled.ExpandMore
+import androidx.compose.material.icons.filled.Gavel
+import androidx.compose.material.icons.filled.Language
+import androidx.compose.material.icons.filled.Notifications
+import androidx.compose.material.icons.filled.Palette
+import androidx.compose.material.icons.filled.Tune
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Switch
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.saveable.rememberSaveable
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.res.colorResource
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.core.content.ContextCompat
+import androidx.core.net.toUri
+import androidx.hilt.navigation.compose.hiltViewModel
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleEventObserver
+import androidx.lifecycle.compose.LocalLifecycleOwner
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.data.prefs.CalendarReminderOverride
+import de.jeanlucmakiola.calendula.data.prefs.ThemeMode
+import de.jeanlucmakiola.calendula.data.prefs.WeekStartPref
+import de.jeanlucmakiola.calendula.domain.EventFormField
+import de.jeanlucmakiola.calendula.ui.common.CollapsingScaffold
+import de.jeanlucmakiola.calendula.ui.common.GroupedRow
+import de.jeanlucmakiola.calendula.ui.common.CalendarColorChip
+import de.jeanlucmakiola.calendula.ui.common.OptionPicker
+import de.jeanlucmakiola.calendula.ui.common.Position
+import de.jeanlucmakiola.calendula.ui.common.REMINDER_PRESETS
+import de.jeanlucmakiola.calendula.ui.common.ReminderDefaultPicker
+import de.jeanlucmakiola.calendula.ui.common.TimePickerAlert
+import de.jeanlucmakiola.calendula.ui.common.positionOf
+import de.jeanlucmakiola.calendula.ui.common.reminderLeadTimeLabel
+import de.jeanlucmakiola.calendula.ui.common.rememberCalendarSlideSpec
+import kotlinx.datetime.LocalTime
+import java.util.Calendar
+
+/** The settings sub-screens reached from the hub's category rows. */
+private enum class SettingsSection { Appearance, EventForm, Notifications }
+
+/**
+ * Token-based accent for a leading icon chip (container / on-container pair).
+ * Neutral chips stay grey; accents are drawn from the M3 scheme so they adapt
+ * to theme, dark mode and dynamic colour.
+ */
+private enum class ChipAccent { Neutral, Primary, Tertiary }
+
+/**
+ * Settings (M4), restructured in v2.3 into a category hub with sub-screens.
+ * Both the hub and the sub-screens use a collapsing [LargeTopAppBar] and the
+ * grouped-row card system. Calendars opens the separate manager hoisted in
+ * [CalendarHost]; Language opens an inline OptionCard dialog; About is a card
+ * at the top. A full-screen destination; [onBack] pops it.
+ */
+@Composable
+fun SettingsScreen(
+    onBack: () -> Unit,
+    onManageCalendars: () -> Unit,
+    modifier: Modifier = Modifier,
+    viewModel: SettingsViewModel = hiltViewModel(),
+) {
+    val state by viewModel.state.collectAsStateWithLifecycle()
+    var section by rememberSaveable { mutableStateOf<SettingsSection?>(null) }
+    val slideSpec = rememberCalendarSlideSpec()
+
+    Box(
+        modifier = modifier
+            .fillMaxSize()
+            .background(MaterialTheme.colorScheme.surface),
+    ) {
+        SettingsHub(
+            onBack = onBack,
+            onOpenSection = { section = it },
+            onManageCalendars = onManageCalendars,
+        )
+
+        AnimatedVisibility(
+            visible = section == SettingsSection.Appearance,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            AppearanceScreen(state = state, viewModel = viewModel, onBack = { section = null })
+        }
+        AnimatedVisibility(
+            visible = section == SettingsSection.EventForm,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            EventFormScreen(state = state, viewModel = viewModel, onBack = { section = null })
+        }
+        AnimatedVisibility(
+            visible = section == SettingsSection.Notifications,
+            enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
+            exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
+        ) {
+            NotificationsScreen(state = state, viewModel = viewModel, onBack = { section = null })
+        }
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Hub
+// ---------------------------------------------------------------------------
+
+@Composable
+private fun SettingsHub(
+    onBack: () -> Unit,
+    onOpenSection: (SettingsSection) -> Unit,
+    onManageCalendars: () -> Unit,
+) {
+    CollapsingScaffold(title = stringResource(R.string.settings_title), onBack = onBack) {
+        Box(Modifier.padding(horizontal = 16.dp)) { AboutCard() }
+        Spacer(Modifier.height(16.dp))
+
+        GroupedRow(
+            title = stringResource(R.string.settings_section_appearance),
+            summary = stringResource(R.string.settings_appearance_subtitle),
+            position = Position.Top,
+            leading = { CategoryIcon(Icons.Default.Palette, ChipAccent.Neutral) },
+            onClick = { onOpenSection(SettingsSection.Appearance) },
+        )
+        GroupedRow(
+            title = stringResource(R.string.settings_section_event_form),
+            summary = stringResource(R.string.settings_event_form_subtitle),
+            position = Position.Middle,
+            leading = { CategoryIcon(Icons.Default.Tune, ChipAccent.Neutral) },
+            onClick = { onOpenSection(SettingsSection.EventForm) },
+        )
+        GroupedRow(
+            title = stringResource(R.string.settings_section_notifications),
+            summary = stringResource(R.string.settings_notifications_subtitle),
+            position = Position.Middle,
+            leading = { CategoryIcon(Icons.Default.Notifications, ChipAccent.Primary) },
+            onClick = { onOpenSection(SettingsSection.Notifications) },
+        )
+        GroupedRow(
+            title = stringResource(R.string.settings_section_calendars),
+            summary = stringResource(R.string.settings_manage_calendars_hint),
+            position = Position.Middle,
+            leading = { CategoryIcon(Icons.Default.CalendarMonth, ChipAccent.Tertiary) },
+            onClick = onManageCalendars,
+        )
+        LanguageRow(position = Position.Bottom)
+
+        AppVersionText()
+    }
+}
+
+@Composable
+private fun LanguageRow(position: Position) {
+    val context = LocalContext.current
+    // Setting a locale recreates the activity; mirror the choice locally so the
+    // row updates instantly even before the recreation lands.
+    var current by remember { mutableStateOf(AppLanguage.currentTag()) }
+    var showDialog by remember { mutableStateOf(false) }
+
+    // null = follow the system; the rest are BCP-47 tags from locales_config.xml.
+    val options = remember { listOf<String?>(null) + AppLanguage.supportedTags(context) }
+
+    GroupedRow(
+        title = stringResource(R.string.settings_language),
+        summary = languageLabel(current),
+        position = position,
+        leading = { CategoryIcon(Icons.Default.Language, ChipAccent.Neutral) },
+        onClick = { showDialog = true },
+    )
+
+    if (showDialog) {
+        OptionPicker(
+            title = stringResource(R.string.settings_language),
+            options = options,
+            selected = current,
+            label = { languageLabel(it) },
+            onSelect = {
+                current = it
+                AppLanguage.apply(it)
+            },
+            onDismiss = { showDialog = false },
+        )
+    }
+}
+
+@Composable
+private fun AboutCard() {
+    val context = LocalContext.current
+    val sourceUrl = stringResource(R.string.about_source_url)
+    val licenseUrl = stringResource(R.string.about_license_url)
+
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        shape = RoundedCornerShape(24.dp),
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Column(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(16.dp),
+        ) {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                AppLogo()
+                Spacer(Modifier.width(16.dp))
+                Column(Modifier.weight(1f)) {
+                    Text(
+                        text = stringResource(R.string.app_name),
+                        style = MaterialTheme.typography.titleLarge,
+                    )
+                    Text(
+                        text = stringResource(R.string.settings_about_author),
+                        style = MaterialTheme.typography.bodyMedium,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                }
+            }
+            Spacer(Modifier.height(12.dp))
+            Row(
+                modifier = Modifier.fillMaxWidth(),
+                horizontalArrangement = Arrangement.spacedBy(8.dp),
+            ) {
+                OutlinedButton(
+                    onClick = { openUrl(context, sourceUrl) },
+                    contentPadding = PaddingValues(horizontal = 12.dp),
+                    modifier = Modifier.weight(1f),
+                ) {
+                    Icon(
+                        painter = painterResource(R.drawable.ic_gitea),
+                        contentDescription = null,
+                        modifier = Modifier.size(18.dp),
+                    )
+                    Spacer(Modifier.width(8.dp))
+                    Text(stringResource(R.string.settings_about_source))
+                }
+                OutlinedButton(
+                    onClick = { openUrl(context, licenseUrl) },
+                    contentPadding = PaddingValues(horizontal = 12.dp),
+                    modifier = Modifier.weight(1f),
+                ) {
+                    Icon(
+                        Icons.Default.Gavel,
+                        contentDescription = null,
+                        modifier = Modifier.size(18.dp),
+                    )
+                    Spacer(Modifier.width(8.dp))
+                    Text(stringResource(R.string.settings_license))
+                }
+            }
+        }
+    }
+}
+
+/** Plain centred version mark at the foot of the settings list (no card). */
+@Composable
+private fun AppVersionText() {
+    val context = LocalContext.current
+    val versionName = remember {
+        runCatching {
+            context.packageManager.getPackageInfo(context.packageName, 0).versionName
+        }.getOrNull() ?: "—"
+    }
+    Text(
+        text = stringResource(R.string.settings_about_version, versionName),
+        style = MaterialTheme.typography.bodySmall,
+        color = MaterialTheme.colorScheme.onSurfaceVariant,
+        textAlign = TextAlign.Center,
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(vertical = 16.dp),
+    )
+}
+
+/**
+ * The app icon as a rounded chip: the off-white launcher mark over its slate
+ * background colour, rendered oversized and clipped to fill the chip the way a
+ * launcher mask would.
+ */
+@Composable
+private fun AppLogo() {
+    Box(
+        modifier = Modifier
+            .size(72.dp)
+            .clip(RoundedCornerShape(20.dp))
+            .background(colorResource(R.color.ic_launcher_background)),
+        contentAlignment = Alignment.Center,
+    ) {
+        Image(
+            painter = painterResource(R.drawable.ic_launcher_foreground),
+            contentDescription = stringResource(R.string.settings_about_logo_desc),
+            modifier = Modifier.requiredSize(108.dp),
+        )
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Sub-screens
+// ---------------------------------------------------------------------------
+
+@Composable
+private fun AppearanceScreen(
+    state: SettingsUiState,
+    viewModel: SettingsViewModel,
+    onBack: () -> Unit,
+) {
+    var showTheme by remember { mutableStateOf(false) }
+    var showWeekStart by remember { mutableStateOf(false) }
+
+    CollapsingScaffold(
+        title = stringResource(R.string.settings_section_appearance),
+        onBack = onBack,
+    ) {
+        GroupedRow(
+            title = stringResource(R.string.settings_theme),
+            summary = themeLabel(state.themeMode),
+            position = Position.Top,
+            onClick = { showTheme = true },
+        )
+        GroupedRow(
+            title = stringResource(R.string.settings_dynamic_color),
+            summary = if (state.dynamicColorAvailable) {
+                null
+            } else {
+                stringResource(R.string.settings_dynamic_color_unavailable)
+            },
+            position = Position.Middle,
+            trailing = {
+                Switch(
+                    checked = state.dynamicColor,
+                    onCheckedChange = viewModel::setDynamicColor,
+                    enabled = state.dynamicColorAvailable,
+                )
+            },
+            onClick = if (state.dynamicColorAvailable) {
+                { viewModel.setDynamicColor(!state.dynamicColor) }
+            } else {
+                null
+            },
+        )
+        GroupedRow(
+            title = stringResource(R.string.settings_week_start),
+            summary = weekStartLabel(state.weekStart),
+            position = Position.Bottom,
+            onClick = { showWeekStart = true },
+        )
+    }
+
+    if (showTheme) {
+        OptionPicker(
+            title = stringResource(R.string.settings_theme),
+            options = ThemeMode.entries,
+            selected = state.themeMode,
+            label = { themeLabel(it) },
+            onSelect = viewModel::setThemeMode,
+            onDismiss = { showTheme = false },
+        )
+    }
+    if (showWeekStart) {
+        OptionPicker(
+            title = stringResource(R.string.settings_week_start),
+            options = WeekStartPref.entries,
+            selected = state.weekStart,
+            label = { weekStartLabel(it) },
+            onSelect = viewModel::setWeekStart,
+            onDismiss = { showWeekStart = false },
+        )
+    }
+}
+
+@Composable
+private fun EventFormScreen(
+    state: SettingsUiState,
+    viewModel: SettingsViewModel,
+    onBack: () -> Unit,
+) {
+    CollapsingScaffold(
+        title = stringResource(R.string.settings_section_event_form),
+        onBack = onBack,
+    ) {
+        Text(
+            text = stringResource(R.string.settings_form_fields_hint),
+            style = MaterialTheme.typography.bodyMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 4.dp),
+        )
+        Spacer(Modifier.height(8.dp))
+        val fields = EventFormField.entries
+        fields.forEachIndexed { index, field ->
+            val checked = field in state.defaultFormFields
+            GroupedRow(
+                title = stringResource(formFieldLabel(field)),
+                position = positionOf(index, fields.size),
+                trailing = {
+                    Switch(
+                        checked = checked,
+                        onCheckedChange = { viewModel.setFormFieldDefault(field, it) },
+                    )
+                },
+                onClick = { viewModel.setFormFieldDefault(field, !checked) },
+            )
+        }
+
+        // Per-event colour on calendars that publish no colour set (some
+        // CalDAV) — off by default, with the honest caveat that the colour may
+        // not survive their next sync. Local and palette calendars ignore it.
+        Spacer(Modifier.height(24.dp))
+        GroupedRow(
+            title = stringResource(R.string.settings_color_unsupported),
+            summary = stringResource(R.string.settings_color_unsupported_hint),
+            position = Position.Alone,
+            trailing = {
+                Switch(
+                    checked = state.allowColorOnUnsupportedCalendars,
+                    onCheckedChange = { viewModel.setAllowColorOnUnsupportedCalendars(it) },
+                )
+            },
+            onClick = {
+                viewModel.setAllowColorOnUnsupportedCalendars(
+                    !state.allowColorOnUnsupportedCalendars,
+                )
+            },
+        )
+    }
+}
+
+/**
+ * Reminder-notifications toggle (v1.4), mirroring the onboarding step.
+ * Turning it on re-requests `POST_NOTIFICATIONS` when missing (API 33+) —
+ * the pref is set either way; the OS permission is the real gate.
+ */
+@Composable
+private fun NotificationsScreen(
+    state: SettingsUiState,
+    viewModel: SettingsViewModel,
+    onBack: () -> Unit,
+) {
+    val context = LocalContext.current
+    val launcher = rememberLauncherForActivityResult(
+        contract = ActivityResultContracts.RequestPermission(),
+    ) { /* The pref is already on; a denial just leaves the OS gate shut. */ }
+    val toggleReminders: (Boolean) -> Unit = { enabled ->
+        viewModel.setRemindersEnabled(enabled)
+        val needsPermission = enabled &&
+            Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU &&
+            ContextCompat.checkSelfPermission(
+                context, Manifest.permission.POST_NOTIFICATIONS,
+            ) != PackageManager.PERMISSION_GRANTED
+        if (needsPermission) {
+            launcher.launch(Manifest.permission.POST_NOTIFICATIONS)
+        }
+    }
+
+    var showDefaultReminder by remember { mutableStateOf(false) }
+    var showAllDayReminder by remember { mutableStateOf(false) }
+    var showAllDayReminderTime by remember { mutableStateOf(false) }
+    var overrideDialog by remember { mutableStateOf<OverrideTarget?>(null) }
+    var expandedCalendars by remember { mutableStateOf(emptySet<Long>()) }
+
+    CollapsingScaffold(
+        title = stringResource(R.string.settings_section_notifications),
+        onBack = onBack,
+    ) {
+        GroupedRow(
+            title = stringResource(R.string.settings_reminders),
+            summary = stringResource(R.string.settings_reminders_hint),
+            position = Position.Top,
+            trailing = {
+                Switch(checked = state.remindersEnabled, onCheckedChange = toggleReminders)
+            },
+            onClick = { toggleReminders(!state.remindersEnabled) },
+        )
+        GroupedRow(
+            title = stringResource(R.string.settings_default_reminder),
+            summary = reminderChoiceLabel(state.defaultReminderMinutes),
+            position = Position.Middle,
+            onClick = { showDefaultReminder = true },
+        )
+        GroupedRow(
+            title = stringResource(R.string.settings_default_reminder_allday),
+            summary = reminderChoiceLabel(state.defaultAllDayReminderMinutes),
+            position = Position.Middle,
+            onClick = { showAllDayReminder = true },
+        )
+        GroupedRow(
+            title = stringResource(R.string.settings_allday_reminder_time),
+            summary = stringResource(
+                R.string.settings_allday_reminder_time_hint,
+                formatTimeOfDay(context, state.allDayReminderTimeMinutes),
+            ),
+            position = Position.Bottom,
+            onClick = { showAllDayReminderTime = true },
+        )
+
+        // Per-calendar overrides: each writable calendar may keep, drop, or
+        // replace the global default — separately for timed and all-day events.
+        if (state.writableCalendars.isNotEmpty()) {
+            Spacer(Modifier.height(24.dp))
+            Text(
+                text = stringResource(R.string.settings_calendar_reminders_hint),
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.padding(horizontal = 16.dp, vertical = 4.dp),
+            )
+            state.writableCalendars.forEach { calendar ->
+                Spacer(Modifier.height(16.dp))
+                val expanded = calendar.id in expandedCalendars
+                // Calendar card; tapping expands it into a grouped list of three
+                // (the card + the timed and all-day override rows).
+                GroupedRow(
+                    title = calendar.displayName,
+                    position = if (expanded) Position.Top else Position.Alone,
+                    leading = { CalendarColorChip(calendar.color) },
+                    trailing = {
+                        Icon(
+                            imageVector = if (expanded) Icons.Default.ExpandLess else Icons.Default.ExpandMore,
+                            contentDescription = null,
+                            tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                        )
+                    },
+                    onClick = {
+                        expandedCalendars = if (expanded) {
+                            expandedCalendars - calendar.id
+                        } else {
+                            expandedCalendars + calendar.id
+                        }
+                    },
+                )
+                AnimatedVisibility(visible = expanded) {
+                    Column {
+                        val timed = state.perCalendarReminderOverride.choiceFor(calendar.id)
+                        GroupedRow(
+                            title = stringResource(R.string.settings_default_reminder),
+                            summary = calendarOverrideSummary(timed, state.defaultReminderMinutes),
+                            position = Position.Middle,
+                            onClick = { overrideDialog = OverrideTarget(calendar.id, isAllDay = false) },
+                        )
+                        val allDay = state.perCalendarAllDayReminderOverride.choiceFor(calendar.id)
+                        GroupedRow(
+                            title = stringResource(R.string.settings_default_reminder_allday),
+                            summary = calendarOverrideSummary(allDay, state.defaultAllDayReminderMinutes),
+                            position = Position.Bottom,
+                            onClick = { overrideDialog = OverrideTarget(calendar.id, isAllDay = true) },
+                        )
+                    }
+                }
+            }
+        }
+
+        // Delivery reliability: Android's battery optimisation can delay or drop
+        // the calendar provider's reminder broadcast. A soft, optional exemption
+        // (system-settings deep-link, no special permission) improves on-time
+        // delivery; shown as live status, reversible by the user at any time.
+        Spacer(Modifier.height(24.dp))
+        val batteryExempt = rememberBatteryOptimizationExempt()
+        GroupedRow(
+            title = stringResource(R.string.settings_reliable_delivery),
+            summary = if (batteryExempt) {
+                stringResource(R.string.settings_reliable_delivery_exempt)
+            } else {
+                stringResource(R.string.settings_reliable_delivery_hint)
+            },
+            position = Position.Alone,
+            trailing = if (batteryExempt) {
+                {
+                    Icon(
+                        imageVector = Icons.Default.Check,
+                        contentDescription = null,
+                        tint = MaterialTheme.colorScheme.primary,
+                    )
+                }
+            } else {
+                null
+            },
+            onClick = { openBatteryOptimizationSettings(context) },
+        )
+    }
+
+    if (showDefaultReminder) {
+        ReminderDefaultPicker(
+            title = stringResource(R.string.settings_default_reminder),
+            presets = REMINDER_PRESETS,
+            selected = state.defaultReminderMinutes.toReminderChoice(),
+            allowInherit = false,
+            onSelect = { viewModel.setDefaultReminderMinutes(it.toMinutesOrNull()) },
+            onDismiss = { showDefaultReminder = false },
+        )
+    }
+    if (showAllDayReminder) {
+        ReminderDefaultPicker(
+            title = stringResource(R.string.settings_default_reminder_allday),
+            presets = ALLDAY_REMINDER_PRESETS,
+            selected = state.defaultAllDayReminderMinutes.toReminderChoice(),
+            allowInherit = false,
+            onSelect = { viewModel.setDefaultAllDayReminderMinutes(it.toMinutesOrNull()) },
+            onDismiss = { showAllDayReminder = false },
+        )
+    }
+    if (showAllDayReminderTime) {
+        TimePickerAlert(
+            initial = LocalTime(
+                state.allDayReminderTimeMinutes / 60,
+                state.allDayReminderTimeMinutes % 60,
+            ),
+            onConfirm = {
+                viewModel.setAllDayReminderTimeMinutes(it.hour * 60 + it.minute)
+                showAllDayReminderTime = false
+            },
+            onDismiss = { showAllDayReminderTime = false },
+        )
+    }
+    overrideDialog?.let { target ->
+        val map = if (target.isAllDay) {
+            state.perCalendarAllDayReminderOverride
+        } else {
+            state.perCalendarReminderOverride
+        }
+        ReminderDefaultPicker(
+            title = stringResource(
+                if (target.isAllDay) {
+                    R.string.settings_default_reminder_allday
+                } else {
+                    R.string.settings_default_reminder
+                },
+            ),
+            presets = if (target.isAllDay) ALLDAY_REMINDER_PRESETS else REMINDER_PRESETS,
+            selected = map.choiceFor(target.calendarId),
+            allowInherit = true,
+            onSelect = {
+                if (target.isAllDay) {
+                    viewModel.setCalendarAllDayReminderOverride(target.calendarId, it)
+                } else {
+                    viewModel.setCalendarReminderOverride(target.calendarId, it)
+                }
+            },
+            onDismiss = { overrideDialog = null },
+        )
+    }
+}
+
+/** Which calendar + event kind a per-calendar reminder-override dialog targets. */
+private data class OverrideTarget(val calendarId: Long, val isAllDay: Boolean)
+
+/** A global default (null = none) as a picker choice for selection highlighting. */
+private fun Int?.toReminderChoice(): CalendarReminderOverride =
+    if (this == null) CalendarReminderOverride.None else CalendarReminderOverride.Minutes(this)
+
+/** A picked choice as global-default minutes (Inherit isn't offered for globals). */
+private fun CalendarReminderOverride.toMinutesOrNull(): Int? =
+    (this as? CalendarReminderOverride.Minutes)?.minutes
+
+/**
+ * Whether Calendula is exempt from battery optimisation, re-read on every
+ * `ON_RESUME` so the row reflects a change the user just made in system
+ * settings without needing to leave and re-enter the screen.
+ */
+@Composable
+private fun rememberBatteryOptimizationExempt(): Boolean {
+    val context = LocalContext.current
+    var exempt by remember { mutableStateOf(isIgnoringBatteryOptimizations(context)) }
+    val lifecycleOwner = LocalLifecycleOwner.current
+    DisposableEffect(lifecycleOwner) {
+        val observer = LifecycleEventObserver { _, event ->
+            if (event == Lifecycle.Event.ON_RESUME) {
+                exempt = isIgnoringBatteryOptimizations(context)
+            }
+        }
+        lifecycleOwner.lifecycle.addObserver(observer)
+        onDispose { lifecycleOwner.lifecycle.removeObserver(observer) }
+    }
+    return exempt
+}
+
+private fun isIgnoringBatteryOptimizations(context: Context): Boolean {
+    val power = context.getSystemService(Context.POWER_SERVICE) as PowerManager
+    return power.isIgnoringBatteryOptimizations(context.packageName)
+}
+
+/**
+ * Take the user straight to Calendula's exemption: the direct
+ * `REQUEST_IGNORE_BATTERY_OPTIMIZATIONS` dialog ("Allow Calendula to ignore
+ * battery optimisation?") rather than the full app list they'd have to scroll.
+ * Falls back to the optimisation list if the OS refuses the direct intent.
+ */
+private fun openBatteryOptimizationSettings(context: Context) {
+    val direct = Intent(
+        Settings.ACTION_REQUEST_IGNORE_BATTERY_OPTIMIZATIONS,
+        "package:${context.packageName}".toUri(),
+    )
+    if (runCatching { context.startActivity(direct) }.isFailure) {
+        runCatching {
+            context.startActivity(Intent(Settings.ACTION_IGNORE_BATTERY_OPTIMIZATION_SETTINGS))
+        }
+    }
+}
+
+/**
+ * Lead times offered for the all-day default — day-scale, since a "minutes
+ * before midnight" reminder on an all-day event is rarely what's wanted.
+ */
+private val ALLDAY_REMINDER_PRESETS = listOf(0, 1_440, 2_880, 10_080)
+
+/** A minute-of-day formatted in the device's 12/24-hour convention (e.g. "09:00"). */
+private fun formatTimeOfDay(context: Context, minutesOfDay: Int): String {
+    val time = Calendar.getInstance().apply {
+        set(Calendar.HOUR_OF_DAY, minutesOfDay / 60)
+        set(Calendar.MINUTE, minutesOfDay % 60)
+    }.time
+    return DateFormat.getTimeFormat(context).format(time)
+}
+
+/** The stored override for [calendarId], as a picker choice (absent → inherit). */
+private fun Map<Long, Int?>.choiceFor(calendarId: Long): CalendarReminderOverride = when {
+    !containsKey(calendarId) -> CalendarReminderOverride.Inherit
+    this[calendarId] == null -> CalendarReminderOverride.None
+    else -> CalendarReminderOverride.Minutes(this.getValue(calendarId)!!)
+}
+
+/** Label for a global-default choice: null → "None", else the lead time. */
+@Composable
+private fun reminderChoiceLabel(minutes: Int?): String =
+    if (minutes == null) stringResource(R.string.reminder_none) else reminderLeadTimeLabel(minutes)
+
+/** Row summary for a calendar: its override, or the inherited global default. */
+@Composable
+private fun calendarOverrideSummary(
+    choice: CalendarReminderOverride,
+    globalDefault: Int?,
+): String = when (choice) {
+    CalendarReminderOverride.Inherit ->
+        stringResource(R.string.settings_calendar_reminder_inherits, reminderChoiceLabel(globalDefault))
+    CalendarReminderOverride.None -> stringResource(R.string.reminder_none)
+    is CalendarReminderOverride.Minutes -> reminderLeadTimeLabel(choice.minutes)
+}
+
+// ---------------------------------------------------------------------------
+// Shared building blocks
+// ---------------------------------------------------------------------------
+
+/**
+ * Leading circular icon chip. Colours come from the M3 scheme via a container /
+ * on-container token pair, so each accent stays correctly paired across theme,
+ * dark mode and dynamic colour.
+ */
+@Composable
+private fun CategoryIcon(icon: ImageVector, accent: ChipAccent) {
+    val scheme = MaterialTheme.colorScheme
+    val (background, iconColor) = when (accent) {
+        ChipAccent.Neutral -> scheme.surfaceContainerHighest to scheme.onSurfaceVariant
+        ChipAccent.Primary -> scheme.primaryContainer to scheme.onPrimaryContainer
+        ChipAccent.Tertiary -> scheme.tertiaryContainer to scheme.onTertiaryContainer
+    }
+    Box(
+        modifier = Modifier
+            .size(40.dp)
+            .clip(CircleShape)
+            .background(background),
+        contentAlignment = Alignment.Center,
+    ) {
+        Icon(
+            imageVector = icon,
+            contentDescription = null,
+            tint = iconColor,
+            modifier = Modifier.size(22.dp),
+        )
+    }
+}
+
+
+private fun openUrl(context: Context, url: String) {
+    val intent = Intent(Intent.ACTION_VIEW, url.toUri())
+    runCatching { context.startActivity(intent) }
+}
+
+private fun formFieldLabel(field: EventFormField): Int = when (field) {
+    EventFormField.Location -> R.string.event_detail_location
+    EventFormField.Description -> R.string.event_detail_description
+    EventFormField.Reminders -> R.string.event_detail_reminders
+    EventFormField.Recurrence -> R.string.event_detail_recurrence
+    EventFormField.Availability -> R.string.event_edit_availability
+    EventFormField.Visibility -> R.string.event_edit_visibility
+    EventFormField.Color -> R.string.event_edit_color
+}
+
+@Composable
+private fun themeLabel(mode: ThemeMode): String = stringResource(
+    when (mode) {
+        ThemeMode.SYSTEM -> R.string.settings_theme_system
+        ThemeMode.LIGHT -> R.string.settings_theme_light
+        ThemeMode.DARK -> R.string.settings_theme_dark
+    },
+)
+
+@Composable
+private fun weekStartLabel(pref: WeekStartPref): String = stringResource(
+    when (pref) {
+        WeekStartPref.AUTO -> R.string.settings_week_start_auto
+        WeekStartPref.MONDAY -> R.string.settings_week_start_monday
+        WeekStartPref.SUNDAY -> R.string.settings_week_start_sunday
+    },
+)
+
+@Composable
+private fun languageLabel(tag: String?): String =
+    if (tag == null) stringResource(R.string.settings_language_auto) else AppLanguage.displayName(tag)

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/SettingsUiState.kt

@@ -0,0 +1,48 @@
+package de.jeanlucmakiola.calendula.ui.settings
+
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.data.prefs.ThemeMode
+import de.jeanlucmakiola.calendula.data.prefs.WeekStartPref
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventFormField
+
+/**
+ * Settings screen state (M4). Persisted preferences are instant to read, so
+ * there is no Loading/Failure here — only a populated Success snapshot.
+ * [dynamicColorAvailable] is false below Android 12, where the toggle is shown
+ * disabled.
+ */
+data class SettingsUiState(
+    val themeMode: ThemeMode = ThemeMode.SYSTEM,
+    val dynamicColor: Boolean = true,
+    val dynamicColorAvailable: Boolean = true,
+    val weekStart: WeekStartPref = WeekStartPref.AUTO,
+    /** Optional event-form fields shown by default (rest behind "more fields"). */
+    val defaultFormFields: Set<EventFormField> = SettingsPrefs.DEFAULT_FORM_FIELDS,
+    /** Whether Calendula posts reminder notifications (v1.4). */
+    val remindersEnabled: Boolean = true,
+    /**
+     * The default reminder lead time (minutes) prefilled on new timed events;
+     * null = no default reminder. Per-calendar overrides take precedence.
+     */
+    val defaultReminderMinutes: Int? = null,
+    /** The default reminder lead time prefilled on new all-day events; null = none. */
+    val defaultAllDayReminderMinutes: Int? = null,
+    /** Wall-clock time (minutes from midnight) all-day reminders fire at; default 09:00. */
+    val allDayReminderTimeMinutes: Int = SettingsPrefs.DEFAULT_ALLDAY_REMINDER_TIME,
+    /**
+     * Per-calendar overrides of [defaultReminderMinutes] for timed events: a
+     * calendar present in the map overrides the global default (null value = no
+     * reminder); absent = inherit the global default.
+     */
+    val perCalendarReminderOverride: Map<Long, Int?> = emptyMap(),
+    /** Per-calendar overrides of [defaultAllDayReminderMinutes] for all-day events. */
+    val perCalendarAllDayReminderOverride: Map<Long, Int?> = emptyMap(),
+    /** Writable calendars, shown as per-calendar reminder-override rows. */
+    val writableCalendars: List<CalendarSource> = emptyList(),
+    /**
+     * Whether the event-colour picker is offered on calendars that publish no
+     * colour palette (the colour may then not survive their next sync).
+     */
+    val allowColorOnUnsupportedCalendars: Boolean = false,
+)

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/SettingsViewModel.kt

@@ -0,0 +1,144 @@
+package de.jeanlucmakiola.calendula.ui.settings
+
+import android.os.Build
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import dagger.hilt.android.lifecycle.HiltViewModel
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.prefs.CalendarReminderOverride
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.data.prefs.ThemeMode
+import de.jeanlucmakiola.calendula.data.prefs.WeekStartPref
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.EventFormField
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.SharingStarted
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import javax.inject.Inject
+
+@HiltViewModel
+class SettingsViewModel @Inject constructor(
+    private val prefs: SettingsPrefs,
+    repository: CalendarRepository,
+) : ViewModel() {
+
+    private val dynamicColorAvailable = Build.VERSION.SDK_INT >= Build.VERSION_CODES.S
+
+    /** Writable calendars — the only ones that take a per-calendar reminder override. */
+    private val writableCalendars: Flow<List<CalendarSource>> = repository.calendars()
+        .map { calendars -> calendars.filter { it.canModifyContents } }
+        .catch { emit(emptyList()) }
+
+    val state: StateFlow<SettingsUiState> =
+        combine(
+            // combine() types up to five flows, so the prefs split into two
+            // groups that fold together in the outer combine.
+            combine(
+                prefs.themeMode,
+                prefs.dynamicColor,
+                prefs.weekStart,
+                prefs.defaultFormFields,
+                prefs.remindersEnabled,
+            ) { theme, dynamic, weekStart, formFields, reminders ->
+                SettingsUiState(
+                    themeMode = theme,
+                    dynamicColor = dynamic && dynamicColorAvailable,
+                    dynamicColorAvailable = dynamicColorAvailable,
+                    weekStart = weekStart,
+                    defaultFormFields = formFields,
+                    remindersEnabled = reminders,
+                )
+            },
+            combine(
+                prefs.allowColorOnUnsupportedCalendars,
+                prefs.defaultReminderMinutes,
+                prefs.defaultAllDayReminderMinutes,
+                prefs.allDayReminderTimeMinutes,
+            ) { allowColor, defaultReminder, allDayReminder, allDayReminderTime ->
+                ReminderDefaults(allowColor, defaultReminder, allDayReminder, allDayReminderTime)
+            },
+            combine(
+                prefs.perCalendarReminderOverride,
+                prefs.perCalendarAllDayReminderOverride,
+                writableCalendars,
+            ) { overrides, allDayOverrides, calendars ->
+                ReminderOverrides(overrides, allDayOverrides, calendars)
+            },
+        ) { base, defaults, overrides ->
+            base.copy(
+                allowColorOnUnsupportedCalendars = defaults.allowColor,
+                defaultReminderMinutes = defaults.defaultReminder,
+                defaultAllDayReminderMinutes = defaults.allDayReminder,
+                allDayReminderTimeMinutes = defaults.allDayReminderTime,
+                perCalendarReminderOverride = overrides.timed,
+                perCalendarAllDayReminderOverride = overrides.allDay,
+                writableCalendars = overrides.calendars,
+            )
+        }.stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = SettingsUiState(dynamicColorAvailable = dynamicColorAvailable),
+        )
+
+    private data class ReminderDefaults(
+        val allowColor: Boolean,
+        val defaultReminder: Int?,
+        val allDayReminder: Int?,
+        val allDayReminderTime: Int,
+    )
+
+    private data class ReminderOverrides(
+        val timed: Map<Long, Int?>,
+        val allDay: Map<Long, Int?>,
+        val calendars: List<CalendarSource>,
+    )
+
+    fun setThemeMode(mode: ThemeMode) {
+        viewModelScope.launch { prefs.setThemeMode(mode) }
+    }
+
+    fun setDynamicColor(enabled: Boolean) {
+        viewModelScope.launch { prefs.setDynamicColor(enabled) }
+    }
+
+    fun setWeekStart(pref: WeekStartPref) {
+        viewModelScope.launch { prefs.setWeekStart(pref) }
+    }
+
+    fun setFormFieldDefault(field: EventFormField, enabled: Boolean) {
+        viewModelScope.launch { prefs.setFormFieldDefault(field, enabled) }
+    }
+
+    fun setRemindersEnabled(enabled: Boolean) {
+        viewModelScope.launch { prefs.setRemindersEnabled(enabled) }
+    }
+
+    fun setDefaultReminderMinutes(minutes: Int?) {
+        viewModelScope.launch { prefs.setDefaultReminderMinutes(minutes) }
+    }
+
+    fun setDefaultAllDayReminderMinutes(minutes: Int?) {
+        viewModelScope.launch { prefs.setDefaultAllDayReminderMinutes(minutes) }
+    }
+
+    fun setAllDayReminderTimeMinutes(minutesOfDay: Int) {
+        viewModelScope.launch { prefs.setAllDayReminderTimeMinutes(minutesOfDay) }
+    }
+
+    fun setCalendarReminderOverride(calendarId: Long, override: CalendarReminderOverride) {
+        viewModelScope.launch { prefs.setCalendarReminderOverride(calendarId, override) }
+    }
+
+    fun setCalendarAllDayReminderOverride(calendarId: Long, override: CalendarReminderOverride) {
+        viewModelScope.launch { prefs.setCalendarAllDayReminderOverride(calendarId, override) }
+    }
+
+    fun setAllowColorOnUnsupportedCalendars(enabled: Boolean) {
+        viewModelScope.launch { prefs.setAllowColorOnUnsupportedCalendars(enabled) }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/theme/Theme.kt

@@ -2,7 +2,9 @@ package de.jeanlucmakiola.calendula.ui.theme
 
 import android.os.Build
 import androidx.compose.foundation.isSystemInDarkTheme
-import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
+import androidx.compose.material3.MaterialExpressiveTheme
+import androidx.compose.material3.MotionScheme
 import androidx.compose.material3.dynamicDarkColorScheme
 import androidx.compose.material3.dynamicLightColorScheme
 import androidx.compose.runtime.Composable
@@ -17,6 +19,7 @@ import androidx.compose.ui.platform.LocalContext
  * The Settings screen (later) can override useDynamicColor and themePreference,
  * but the V1 foundation just follows the system.
  */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
 @Composable
 fun CalendulaTheme(
     darkTheme: Boolean = isSystemInDarkTheme(),
@@ -32,9 +35,15 @@ fun CalendulaTheme(
         else -> CalendulaLightFallback
     }
 
-    MaterialTheme(
+    // MaterialExpressiveTheme routes all component + custom motion through
+    // MaterialTheme.motionScheme (switches, chips, pickers, calendar slide,
+    // FAB, field reveal). The STANDARD scheme is a deliberate choice over
+    // expressive(): same spring choreography, but without the overshoot —
+    // the bouncy variant felt overdone in review (2026-06-11).
+    MaterialExpressiveTheme(
         colorScheme = colorScheme,
         typography = CalendulaTypography,
+        motionScheme = MotionScheme.standard(),
         content = content,
     )
 }

app/src/main/java/de/jeanlucmakiola/calendula/ui/week/WeekScreen.kt

@@ -1,13 +1,12 @@
 package de.jeanlucmakiola.calendula.ui.week
 
 import androidx.compose.animation.AnimatedContent
-import androidx.compose.animation.AnimatedVisibility
 import androidx.compose.animation.animateColorAsState
 import androidx.compose.animation.core.animateDpAsState
-import androidx.compose.animation.scaleIn
-import androidx.compose.animation.scaleOut
 import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.gestures.detectHorizontalDragGestures
+import androidx.compose.foundation.gestures.detectTapGestures
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -30,12 +29,10 @@ import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Menu
-import androidx.compose.material.icons.filled.Refresh
 import androidx.compose.material3.Card
 import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.DrawerValue
 import androidx.compose.material3.ExperimentalMaterial3Api
-import androidx.compose.material3.ExtendedFloatingActionButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
@@ -76,6 +73,7 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.calendula.R
 import de.jeanlucmakiola.calendula.domain.EventInstance
 import de.jeanlucmakiola.calendula.ui.common.CalendarDrawer
+import de.jeanlucmakiola.calendula.ui.common.CalendarFabColumn
 import de.jeanlucmakiola.calendula.ui.common.CalendarFailure
 import de.jeanlucmakiola.calendula.ui.common.CalendarView
 import de.jeanlucmakiola.calendula.ui.common.ViewSwitcherPill
@@ -86,9 +84,11 @@ import de.jeanlucmakiola.calendula.ui.common.next
 import de.jeanlucmakiola.calendula.ui.common.pastelize
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
-import kotlinx.datetime.DayOfWeek
 import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
 import kotlinx.datetime.plus
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Clock
 import java.time.format.TextStyle as JavaTextStyle
 import java.util.Locale
 import kotlin.math.roundToInt
@@ -111,6 +111,9 @@ private fun WeekUiState.Success.allDayStripHeight(): Dp {
 fun WeekScreen(
     selectedView: CalendarView,
     onSelectView: (CalendarView) -> Unit,
+    onEventClick: (EventInstance) -> Unit,
+    onOpenSettings: () -> Unit,
+    onCreateEvent: (LocalDate, Int?) -> Unit,
     modifier: Modifier = Modifier,
     viewModel: WeekViewModel = hiltViewModel(),
 ) {
@@ -133,7 +136,10 @@ fun WeekScreen(
     )
 
     val isOnCurrentWeek = when (val s = state) {
-        is WeekUiState.Success -> s.weekStart == s.today.startOfWeek(DayOfWeek.MONDAY)
+        // True when today falls inside the displayed week — independent of which
+        // weekday the user picked as the first day.
+        is WeekUiState.Success ->
+            s.today >= s.weekStart && s.today <= s.weekStart.plus(6, kotlinx.datetime.DateTimeUnit.DAY)
         else -> true
     }
 
@@ -141,7 +147,20 @@ fun WeekScreen(
     var slideDir by remember { mutableIntStateOf(0) }
     val goNext = { slideDir = 1; viewModel.goToNext() }
     val goPrev = { slideDir = -1; viewModel.goToPrev() }
-    val jumpToToday = { slideDir = 0; viewModel.goToToday() }
+    // Slide toward today: viewing the future → today comes in from the left
+    // (back), viewing the past → from the right (forward).
+    val jumpToToday = {
+        slideDir = when (val s = state) {
+            is WeekUiState.Success -> if (s.today < s.weekStart) -1 else 1
+            else -> 0
+        }
+        viewModel.goToToday()
+    }
+    // Drawer jump-to-date: slide from the side the target week lies on.
+    val jumpToDate: (LocalDate) -> Unit = { target ->
+        slideDir = if (target < weekStart) -1 else 1
+        viewModel.goToDate(target)
+    }
 
     ModalNavigationDrawer(
         drawerState = drawerState,
@@ -149,10 +168,20 @@ fun WeekScreen(
         gesturesEnabled = drawerState.isOpen,
         drawerContent = {
             CalendarDrawer(
-                onToday = { jumpToToday(); scope.launch { drawerState.close() } },
-                onJumpToDate = { scope.launch { drawerState.close() } /* TODO: date picker */ },
-                onFilter = { scope.launch { drawerState.close() } /* TODO: filter sheet */ },
-                onSettings = { scope.launch { drawerState.close() } /* TODO: settings */ },
+                currentView = selectedView,
+                currentDate = weekStart,
+                onSelectView = { view ->
+                    onSelectView(view)
+                    scope.launch { drawerState.close() }
+                },
+                onJumpToDate = { target ->
+                    jumpToDate(target)
+                    scope.launch { drawerState.close() }
+                },
+                onSettings = {
+                    onOpenSettings()
+                    scope.launch { drawerState.close() }
+                },
             )
         },
     ) {
@@ -168,17 +197,17 @@ fun WeekScreen(
                 )
             },
             floatingActionButton = {
-                AnimatedVisibility(
-                    visible = !isOnCurrentWeek,
-                    enter = scaleIn(),
-                    exit = scaleOut(),
-                ) {
-                    ExtendedFloatingActionButton(
-                        onClick = jumpToToday,
-                        icon = { Icon(Icons.Default.Refresh, contentDescription = null) },
-                        text = { Text(stringResource(R.string.week_today_action)) },
+                CalendarFabColumn(
+                    todayVisible = !isOnCurrentWeek,
+                    todayText = stringResource(R.string.week_today_action),
+                    onToday = jumpToToday,
+                    onCreate = {
+                        // Anchor on today when it's in view, else the week's first day.
+                        val today = Clock.System.now()
+                            .toLocalDateTime(TimeZone.currentSystemDefault()).date
+                        onCreateEvent(if (isOnCurrentWeek) today else weekStart, null)
+                    },
                 )
-                }
             },
         ) { innerPadding ->
             WeekContent(
@@ -188,6 +217,8 @@ fun WeekScreen(
                 onSwipeNext = goNext,
                 onSwipePrev = goPrev,
                 onRetry = jumpToToday,
+                onEventClick = onEventClick,
+                onCreateAt = { d, minutes -> onCreateEvent(d, minutes) },
                 modifier = Modifier
                     .padding(innerPadding)
                     .fillMaxSize(),
@@ -204,6 +235,8 @@ private fun WeekContent(
     onSwipeNext: () -> Unit,
     onSwipePrev: () -> Unit,
     onRetry: () -> Unit,
+    onEventClick: (EventInstance) -> Unit,
+    onCreateAt: (LocalDate, Int) -> Unit,
     modifier: Modifier = Modifier,
 ) {
     val density = LocalDensity.current
@@ -274,6 +307,8 @@ private fun WeekContent(
                 topSectionColor = topSectionColor,
                 scrollState = scrollState,
                 allDayHeight = allDayHeight,
+                onEventClick = onEventClick,
+                onCreateAt = onCreateAt,
             )
         }
     }
@@ -285,6 +320,8 @@ private fun WeekSuccess(
     topSectionColor: Color,
     scrollState: ScrollState,
     allDayHeight: Dp,
+    onEventClick: (EventInstance) -> Unit,
+    onCreateAt: (LocalDate, Int) -> Unit,
 ) {
     Column(modifier = Modifier.fillMaxSize()) {
         Column(
@@ -293,12 +330,17 @@ private fun WeekSuccess(
                 .background(topSectionColor),
         ) {
             WeekDayHeader(days = state.days, today = state.today)
-            AllDayStrip(state = state, height = allDayHeight)
+            AllDayStrip(state = state, height = allDayHeight, onEventClick = onEventClick)
         }
         // Breathing room between the (colour-shifting) top section and the
         // scrolling timeline below.
         Spacer(Modifier.height(8.dp))
-        Timeline(state = state, scrollState = scrollState)
+        Timeline(
+            state = state,
+            scrollState = scrollState,
+            onEventClick = onEventClick,
+            onCreateAt = onCreateAt,
+        )
     }
 }
 
@@ -433,7 +475,11 @@ private fun WeekNumberBadge(weekNumber: Int, modifier: Modifier = Modifier) {
 }
 
 @Composable
-private fun AllDayStrip(state: WeekUiState.Success, height: Dp) {
+private fun AllDayStrip(
+    state: WeekUiState.Success,
+    height: Dp,
+    onEventClick: (EventInstance) -> Unit,
+) {
     val dark = isSystemInDarkTheme()
 
     Row(
@@ -461,6 +507,7 @@ private fun AllDayStrip(state: WeekUiState.Success, height: Dp) {
                 AllDayBar(
                     event = span.event,
                     dark = dark,
+                    onClick = { onEventClick(span.event) },
                     modifier = Modifier
                         .offset(
                             x = colWidth * span.startCol,
@@ -476,11 +523,17 @@ private fun AllDayStrip(state: WeekUiState.Success, height: Dp) {
 }
 
 @Composable
-private fun AllDayBar(event: EventInstance, dark: Boolean, modifier: Modifier = Modifier) {
+private fun AllDayBar(
+    event: EventInstance,
+    dark: Boolean,
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
     val title = event.title.ifBlank { stringResource(R.string.event_untitled) }
     Box(
         modifier = modifier
             .background(pastelize(event.color, dark), RoundedCornerShape(4.dp))
+            .clickable(onClick = onClick)
             .padding(horizontal = 6.dp, vertical = 2.dp)
             .semantics { contentDescription = title },
         contentAlignment = Alignment.CenterStart,
@@ -496,7 +549,12 @@ private fun AllDayBar(event: EventInstance, dark: Boolean, modifier: Modifier =
 }
 
 @Composable
-private fun Timeline(state: WeekUiState.Success, scrollState: ScrollState) {
+private fun Timeline(
+    state: WeekUiState.Success,
+    scrollState: ScrollState,
+    onEventClick: (EventInstance) -> Unit,
+    onCreateAt: (LocalDate, Int) -> Unit,
+) {
     val totalHeight = HOUR_HEIGHT * 24
     val dark = isSystemInDarkTheme()
 
@@ -551,6 +609,9 @@ private fun Timeline(state: WeekUiState.Success, scrollState: ScrollState) {
                         DayColumnCard(
                             blocks = state.timedByDay[day].orEmpty(),
                             dark = dark,
+                            date = day,
+                            onEventClick = onEventClick,
+                            onCreateAt = onCreateAt,
                             modifier = Modifier
                                 .weight(1f)
                                 .fillMaxHeight(),
@@ -566,8 +627,12 @@ private fun Timeline(state: WeekUiState.Success, scrollState: ScrollState) {
 private fun DayColumnCard(
     blocks: List<TimedBlock>,
     dark: Boolean,
+    date: LocalDate,
+    onEventClick: (EventInstance) -> Unit,
+    onCreateAt: (LocalDate, Int) -> Unit,
     modifier: Modifier = Modifier,
 ) {
+    val hourPx = with(LocalDensity.current) { HOUR_HEIGHT.toPx() }
     Card(
         // Plain rectangular columns — the soft corners come from the outer
         // rounded scroll viewport, so inner rounding would look odd at the edges.
@@ -577,7 +642,18 @@ private fun DayColumnCard(
         ),
         modifier = modifier,
     ) {
-        BoxWithConstraints(modifier = Modifier.fillMaxSize()) {
+        BoxWithConstraints(
+            modifier = Modifier
+                .fillMaxSize()
+                // Tap an empty slot to create an event there; taps on event
+                // blocks are consumed by their own handler first. Snaps to hour.
+                .pointerInput(date) {
+                    detectTapGestures { offset ->
+                        val hour = (offset.y / hourPx).toInt().coerceIn(0, 23)
+                        onCreateAt(date, hour * 60)
+                    }
+                },
+        ) {
             val colWidth = maxWidth
             blocks.forEach { block ->
                 val laneWidth = colWidth / block.laneCount
@@ -587,6 +663,7 @@ private fun DayColumnCard(
                 EventBlock(
                     block = block,
                     dark = dark,
+                    onClick = { onEventClick(block.event) },
                     modifier = Modifier
                         .offset(x = laneWidth * block.lane, y = top)
                         .width(laneWidth)
@@ -602,6 +679,7 @@ private fun DayColumnCard(
 private fun EventBlock(
     block: TimedBlock,
     dark: Boolean,
+    onClick: () -> Unit,
     modifier: Modifier = Modifier,
 ) {
     val title = block.event.title.ifBlank { stringResource(R.string.event_untitled) }
@@ -610,6 +688,7 @@ private fun EventBlock(
     Box(
         modifier = modifier
             .background(pastelize(block.event.color, dark), RoundedCornerShape(4.dp))
+            .clickable(onClick = onClick)
             .padding(horizontal = 4.dp, vertical = 2.dp)
             .semantics { contentDescription = "$title, $timeLabel" },
     ) {

app/src/main/java/de/jeanlucmakiola/calendula/ui/week/WeekViewModel.kt

@@ -5,6 +5,8 @@ import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
 import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+import de.jeanlucmakiola.calendula.data.prefs.resolveFirstDay
 import de.jeanlucmakiola.calendula.domain.CalendarSource
 import de.jeanlucmakiola.calendula.domain.EventInstance
 import de.jeanlucmakiola.calendula.domain.FailureReason
@@ -15,8 +17,10 @@ import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.flatMapLatest
 import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.datetime.DateTimeUnit
 import kotlinx.datetime.DayOfWeek
@@ -28,6 +32,7 @@ import kotlinx.datetime.minus
 import kotlinx.datetime.plus
 import kotlinx.datetime.toInstant
 import kotlinx.datetime.toLocalDateTime
+import java.util.Locale
 import kotlin.time.Clock
 import kotlin.time.Instant
 import javax.inject.Inject
@@ -38,21 +43,41 @@ const val MINUTES_PER_DAY: Int = 24 * 60
 @HiltViewModel
 class WeekViewModel @Inject constructor(
     private val repository: CalendarRepository,
+    settingsPrefs: SettingsPrefs,
     @IoDispatcher private val io: CoroutineDispatcher,
 ) : ViewModel() {
 
     private val zone = TimeZone.currentSystemDefault()
-
-    // V1: week starts Monday. DataStore-driven preference comes with Settings.
-    private val weekStart: DayOfWeek = DayOfWeek.MONDAY
+    private val locale: Locale = Locale.getDefault()
 
     private val todayDate: LocalDate
         get() = Clock.System.now().toLocalDateTime(zone).date
 
-    private val _weekStartDate = MutableStateFlow(todayDate.startOfWeek(weekStart))
-    val weekStartDate: StateFlow<LocalDate> = _weekStartDate
+    /** First day of the week, from the Settings preference (AUTO → locale). */
+    private val weekStart: StateFlow<DayOfWeek> = settingsPrefs.weekStart
+        .map { it.resolveFirstDay(locale) }
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = DayOfWeek.MONDAY,
+        )
 
-    val state: StateFlow<WeekUiState> = _weekStartDate
+    // Anchor is a representative day inside the visible week; the actual week
+    // start is derived against [weekStart], so changing the first-day preference
+    // re-frames the same week instead of jumping.
+    private val _anchor = MutableStateFlow(todayDate)
+
+    val weekStartDate: StateFlow<LocalDate> =
+        combine(_anchor, weekStart) { anchor, ws -> anchor.startOfWeek(ws) }
+            .stateIn(
+                scope = viewModelScope,
+                started = SharingStarted.WhileSubscribed(5_000L),
+                initialValue = todayDate.startOfWeek(DayOfWeek.MONDAY),
+            )
+
+    val state: StateFlow<WeekUiState> =
+        combine(_anchor, weekStart) { anchor, ws -> anchor.startOfWeek(ws) }
+            .distinctUntilChanged()
             .flatMapLatest { start ->
                 val range = weekRange(start, zone)
                 combine(
@@ -71,15 +96,20 @@ class WeekViewModel @Inject constructor(
             )
 
     fun goToPrev() {
-        _weekStartDate.value = _weekStartDate.value.minus(7, DateTimeUnit.DAY)
+        _anchor.value = _anchor.value.minus(7, DateTimeUnit.DAY)
     }
 
     fun goToNext() {
-        _weekStartDate.value = _weekStartDate.value.plus(7, DateTimeUnit.DAY)
+        _anchor.value = _anchor.value.plus(7, DateTimeUnit.DAY)
     }
 
     fun goToToday() {
-        _weekStartDate.value = todayDate.startOfWeek(weekStart)
+        _anchor.value = todayDate
+    }
+
+    /** Jump to the week containing [date] (drawer jump-to-date). */
+    fun goToDate(date: LocalDate) {
+        _anchor.value = date
     }
 
     private fun buildState(
@@ -151,6 +181,18 @@ internal fun weekRange(start: LocalDate, zone: TimeZone): ClosedRange<Instant> {
 
 /** True if this event overlaps the calendar [day] in [zone] (any portion). */
 internal fun EventInstance.coversDay(day: LocalDate, zone: TimeZone): Boolean {
+    if (isAllDay) {
+        // All-day events live at UTC midnights with an exclusive end. Compare
+        // calendar dates in UTC and step the exclusive end back to the last
+        // covered day (mirroring the detail/edit views), so a one-day event
+        // covers exactly its single date. Slicing the day in the device zone
+        // would push the exclusive end a few hours into the next local day
+        // east of UTC, making the event leak onto day + 1.
+        val startDate = start.toLocalDateTime(TimeZone.UTC).date
+        val endExclusive = end.toLocalDateTime(TimeZone.UTC).date
+        val lastDay = maxOf(startDate, endExclusive.minus(1, DateTimeUnit.DAY))
+        return day in startDate..lastDay
+    }
     val dayStart = day.atStartOfDayIn(zone)
     val dayEnd = day.plus(1, DateTimeUnit.DAY).atStartOfDayIn(zone)
     return start < dayEnd && end > dayStart

app/src/main/java/de/jeanlucmakiola/calendula/widget/WidgetData.kt

@@ -0,0 +1,113 @@
+package de.jeanlucmakiola.calendula.widget
+
+import android.Manifest
+import android.content.Context
+import android.content.pm.PackageManager
+import androidx.core.content.ContextCompat
+import de.jeanlucmakiola.calendula.data.prefs.resolveFirstDay
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.ui.agenda.AgendaDay
+import de.jeanlucmakiola.calendula.ui.agenda.agendaRange
+import de.jeanlucmakiola.calendula.ui.agenda.groupAgendaDays
+import kotlinx.coroutines.flow.first
+import kotlinx.datetime.DateTimeUnit
+import kotlinx.datetime.DayOfWeek
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.atStartOfDayIn
+import kotlinx.datetime.atTime
+import kotlinx.datetime.minus
+import kotlinx.datetime.plus
+import kotlinx.datetime.toInstant
+import kotlinx.datetime.toLocalDateTime
+import java.util.Locale
+import kotlin.time.Clock
+
+/** How far ahead the agenda widget loads (a month of upcoming events). */
+private const val AGENDA_WIDGET_DAYS = 30
+
+/**
+ * How far either side of today the month widget pre-loads. The displayed month
+ * is chosen reactively in the composition, so one wide read covers ~13 months of
+ * prev/next navigation without re-querying on every arrow tap.
+ */
+private const val MONTH_WIDGET_RANGE_DAYS = 400
+
+internal fun systemZone(): TimeZone = TimeZone.currentSystemDefault()
+
+internal fun today(zone: TimeZone): LocalDate =
+    Clock.System.now().toLocalDateTime(zone).date
+
+internal fun Context.hasCalendarPermission(): Boolean =
+    ContextCompat.checkSelfPermission(this, Manifest.permission.READ_CALENDAR) ==
+        PackageManager.PERMISSION_GRANTED
+
+/** Snapshot rendered by the agenda widget. */
+sealed interface AgendaWidgetData {
+    /** Calendar permission not granted — the widget can't read events. */
+    data object NeedsPermission : AgendaWidgetData
+    data class Ready(val today: LocalDate, val days: List<AgendaDay>) : AgendaWidgetData
+}
+
+/**
+ * Source data for the month widget: a wide window of instances plus the
+ * week-start preference and today. The widget computes each displayed month's
+ * grid from this in-memory list (via `layoutMonthWeeks`) as the user pages,
+ * so month navigation is pure recomposition — no reload, no flaky widget
+ * session restart.
+ */
+sealed interface MonthWidgetSource {
+    data object NeedsPermission : MonthWidgetSource
+    data class Ready(
+        val today: LocalDate,
+        val weekStart: DayOfWeek,
+        val instances: List<EventInstance>,
+    ) : MonthWidgetSource
+}
+
+/**
+ * Process-lived cache of the wide month window. Month navigation re-runs
+ * `provideGlance` (via `updateAll`), and re-querying ~13 months of instances on
+ * every arrow tap is what made paging feel sluggish — so we load once and reuse
+ * the same snapshot for every nearby month. Invalidated by
+ * [invalidateMonthWidgetCache] when calendar data changes (the freshness
+ * receiver), and automatically when the day rolls over (the `today` guard).
+ */
+internal object MonthWidgetCache {
+    @Volatile
+    var data: MonthWidgetSource.Ready? = null
+}
+
+internal fun invalidateMonthWidgetCache() {
+    MonthWidgetCache.data = null
+}
+
+/**
+ * One-shot read of the upcoming agenda for the widget. Reuses the app's
+ * [agendaRange] window and [groupAgendaDays] grouping, and the repository's
+ * [first]-emitted snapshot already has hidden calendars filtered out.
+ */
+internal suspend fun Context.loadAgendaWidgetData(): AgendaWidgetData {
+    if (!hasCalendarPermission()) return AgendaWidgetData.NeedsPermission
+    val zone = systemZone()
+    val anchor = today(zone)
+    val repo = widgetEntryPoint().calendarRepository()
+    val instances = repo.instances(agendaRange(anchor, AGENDA_WIDGET_DAYS, zone)).first()
+    return AgendaWidgetData.Ready(today = anchor, days = groupAgendaDays(anchor, instances, zone))
+}
+
+/** One-shot wide read backing the month widget's grid for any nearby month. */
+internal suspend fun Context.loadMonthWidgetSource(): MonthWidgetSource {
+    if (!hasCalendarPermission()) return MonthWidgetSource.NeedsPermission
+    val zone = systemZone()
+    val anchor = today(zone)
+    // Reuse the cached window unless the day changed (then it's stale for "today").
+    MonthWidgetCache.data?.let { if (it.today == anchor) return it }
+    val ep = widgetEntryPoint()
+    val weekStart = ep.settingsPrefs().weekStart.first().resolveFirstDay(Locale.getDefault())
+    val from = anchor.minus(MONTH_WIDGET_RANGE_DAYS, DateTimeUnit.DAY).atStartOfDayIn(zone)
+    val to = anchor.plus(MONTH_WIDGET_RANGE_DAYS, DateTimeUnit.DAY).atTime(23, 59, 59).toInstant(zone)
+    val instances = ep.calendarRepository().instances(from..to).first()
+    return MonthWidgetSource.Ready(today = anchor, weekStart = weekStart, instances = instances)
+        .also { MonthWidgetCache.data = it }
+}

app/src/main/java/de/jeanlucmakiola/calendula/widget/WidgetEntryPoint.kt

@@ -0,0 +1,27 @@
+package de.jeanlucmakiola.calendula.widget
+
+import android.content.Context
+import dagger.hilt.EntryPoint
+import dagger.hilt.InstallIn
+import dagger.hilt.android.EntryPointAccessors
+import dagger.hilt.components.SingletonComponent
+import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
+
+/**
+ * Hilt bridge for the Glance widgets. A [androidx.glance.appwidget.GlanceAppWidget]
+ * is instantiated by the framework, not by Hilt, so it can't take constructor
+ * injection. We instead reach the singleton graph through this entry point and
+ * read the same [CalendarRepository] / [SettingsPrefs] the app uses — so widget
+ * data (hidden-calendar filtering, week-start preference, …) matches the app
+ * one-to-one.
+ */
+@EntryPoint
+@InstallIn(SingletonComponent::class)
+interface WidgetEntryPoint {
+    fun calendarRepository(): CalendarRepository
+    fun settingsPrefs(): SettingsPrefs
+}
+
+internal fun Context.widgetEntryPoint(): WidgetEntryPoint =
+    EntryPointAccessors.fromApplication(applicationContext, WidgetEntryPoint::class.java)

app/src/main/java/de/jeanlucmakiola/calendula/widget/WidgetTheme.kt

@@ -0,0 +1,36 @@
+package de.jeanlucmakiola.calendula.widget
+
+import android.os.Build
+import androidx.compose.runtime.Composable
+import androidx.glance.GlanceTheme
+import androidx.glance.material3.ColorProviders
+import de.jeanlucmakiola.calendula.ui.theme.CalendulaDarkFallback
+import de.jeanlucmakiola.calendula.ui.theme.CalendulaLightFallback
+
+/**
+ * Brand fallback for devices without Material You dynamic colour (API < 31).
+ * Reuses the exact same hand-tuned schemes as the in-app theme
+ * ([CalendulaLightFallback] / [CalendulaDarkFallback]) so a widget on an older
+ * device matches the app surface-for-surface.
+ */
+private val CalendulaGlanceColors = ColorProviders(
+    light = CalendulaLightFallback,
+    dark = CalendulaDarkFallback,
+)
+
+/**
+ * Glance equivalent of `CalendulaTheme`. On API 31+ it follows the system's
+ * Material You palette (so the widget matches the home screen / the app's
+ * dynamic colour); below that it falls back to the brand scheme. Either way the
+ * widget draws only from M3 colour-role tokens (`GlanceTheme.colors.*`) — never
+ * a hardcoded colour — so it tracks light/dark automatically.
+ */
+@Composable
+fun CalendulaGlanceTheme(content: @Composable () -> Unit) {
+    val colors = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
+        GlanceTheme.colors
+    } else {
+        CalendulaGlanceColors
+    }
+    GlanceTheme(colors = colors, content = content)
+}

app/src/main/java/de/jeanlucmakiola/calendula/widget/WidgetUpdateReceiver.kt

@@ -0,0 +1,41 @@
+package de.jeanlucmakiola.calendula.widget
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import androidx.glance.appwidget.updateAll
+import de.jeanlucmakiola.calendula.widget.agenda.AgendaWidget
+import de.jeanlucmakiola.calendula.widget.month.MonthWidget
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.launch
+
+/**
+ * Redraws both home-screen widgets when their data goes stale. Triggered by:
+ *  - `PROVIDER_CHANGED` from the calendar provider — fires on any data change,
+ *    so it covers both the app's own writes and external sync.
+ *  - `DATE_CHANGED` / `TIME_SET` / `TIMEZONE_CHANGED` — so "today" highlighting
+ *    and the upcoming window roll over at midnight / on a clock change.
+ *
+ * Both widgets also carry an `updatePeriodMillis` backstop in their provider
+ * XML, and the month widget's refresh button forces an immediate redraw.
+ */
+class WidgetUpdateReceiver : BroadcastReceiver() {
+    override fun onReceive(context: Context, intent: Intent) {
+        val pending = goAsync()
+        val appContext = context.applicationContext
+        // Calendar data may have changed (sync / our own write) — drop the cached
+        // month window so the widgets reload fresh. Month paging does NOT call
+        // this, so arrow taps stay instant.
+        invalidateMonthWidgetCache()
+        CoroutineScope(SupervisorJob() + Dispatchers.IO).launch {
+            try {
+                AgendaWidget().updateAll(appContext)
+                MonthWidget().updateAll(appContext)
+            } finally {
+                pending.finish()
+            }
+        }
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/widget/agenda/AgendaWidget.kt

@@ -0,0 +1,279 @@
+package de.jeanlucmakiola.calendula.widget.agenda
+
+import android.content.Context
+import android.content.res.Configuration
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import androidx.glance.ColorFilter
+import androidx.glance.GlanceId
+import androidx.glance.GlanceModifier
+import androidx.glance.GlanceTheme
+import androidx.glance.Image
+import androidx.glance.ImageProvider
+import androidx.glance.action.ActionParameters
+import androidx.glance.action.clickable
+import androidx.glance.appwidget.GlanceAppWidget
+import androidx.glance.appwidget.action.ActionCallback
+import androidx.glance.appwidget.action.actionRunCallback
+import androidx.glance.appwidget.action.actionStartActivity
+import androidx.glance.appwidget.cornerRadius
+import androidx.glance.appwidget.lazy.LazyColumn
+import androidx.glance.appwidget.lazy.items
+import androidx.glance.appwidget.provideContent
+import androidx.glance.appwidget.updateAll
+import androidx.glance.background
+import androidx.glance.layout.Alignment
+import androidx.glance.layout.Box
+import androidx.glance.layout.Column
+import androidx.glance.layout.Row
+import androidx.glance.layout.Spacer
+import androidx.glance.layout.fillMaxSize
+import androidx.glance.layout.fillMaxWidth
+import androidx.glance.layout.height
+import androidx.glance.layout.padding
+import androidx.glance.layout.size
+import androidx.glance.layout.width
+import androidx.glance.text.FontWeight
+import androidx.glance.text.Text
+import androidx.glance.text.TextStyle
+import de.jeanlucmakiola.calendula.MainActivity
+import de.jeanlucmakiola.calendula.R
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.ui.common.pastelize
+import de.jeanlucmakiola.calendula.widget.AgendaWidgetData
+import de.jeanlucmakiola.calendula.widget.CalendulaGlanceTheme
+import de.jeanlucmakiola.calendula.widget.loadAgendaWidgetData
+import de.jeanlucmakiola.calendula.widget.systemZone
+import de.jeanlucmakiola.calendula.widget.today
+import kotlinx.datetime.DateTimeUnit
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.plus
+import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Instant
+import java.time.format.TextStyle as JavaTextStyle
+import java.util.Locale
+
+/**
+ * "Upcoming" agenda widget — a continuously scrolling list of the next ~30 days
+ * of events grouped under day headers (the Google "Schedule" widget model).
+ * Reuses the app's [groupAgendaDays] grouping so it matches the in-app agenda.
+ */
+class AgendaWidget : GlanceAppWidget() {
+
+    override suspend fun provideGlance(context: Context, id: GlanceId) {
+        val data = context.loadAgendaWidgetData()
+        val dark = (context.resources.configuration.uiMode and
+            Configuration.UI_MODE_NIGHT_MASK) == Configuration.UI_MODE_NIGHT_YES
+        provideContent {
+            CalendulaGlanceTheme {
+                AgendaWidgetBody(data = data, dark = dark)
+            }
+        }
+    }
+}
+
+/** Re-reads the calendar and redraws the widget (header refresh button). */
+class RefreshAgendaAction : ActionCallback {
+    override suspend fun onAction(context: Context, glanceId: GlanceId, parameters: ActionParameters) {
+        AgendaWidget().updateAll(context.applicationContext)
+    }
+}
+
+/** Flat row model so the [LazyColumn] can mix day headers and events. */
+private sealed interface AgendaRow {
+    data class Header(val date: LocalDate, val today: LocalDate) : AgendaRow
+    data class Event(val event: EventInstance) : AgendaRow
+}
+
+@Composable
+private fun AgendaWidgetBody(data: AgendaWidgetData, dark: Boolean) {
+    Column(
+        modifier = GlanceModifier
+            .fillMaxSize()
+            .background(GlanceTheme.colors.surface)
+            .padding(horizontal = 8.dp, vertical = 6.dp),
+    ) {
+        AgendaHeader()
+        Spacer(GlanceModifier.height(4.dp))
+        when (data) {
+            AgendaWidgetData.NeedsPermission -> WidgetMessage(R.string.widget_needs_permission)
+            is AgendaWidgetData.Ready ->
+                if (data.days.isEmpty()) {
+                    WidgetMessage(R.string.agenda_empty_title)
+                } else {
+                    val rows = buildList {
+                        data.days.forEach { day ->
+                            add(AgendaRow.Header(day.date, data.today))
+                            day.events.forEach { add(AgendaRow.Event(it)) }
+                        }
+                    }
+                    LazyColumn(modifier = GlanceModifier.fillMaxSize()) {
+                        items(rows.size) { index ->
+                            when (val row = rows[index]) {
+                                is AgendaRow.Header -> DayHeaderRow(row.date, row.today)
+                                is AgendaRow.Event -> EventRow(row.event, dark)
+                            }
+                        }
+                    }
+                }
+        }
+    }
+}
+
+@Composable
+private fun AgendaHeader() {
+    val context = androidx.glance.LocalContext.current
+    Row(
+        modifier = GlanceModifier.fillMaxWidth().padding(horizontal = 4.dp),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Text(
+            text = context.getString(R.string.widget_agenda_title),
+            style = TextStyle(
+                color = GlanceTheme.colors.primary,
+                fontSize = 16.sp,
+                fontWeight = FontWeight.Medium,
+            ),
+            modifier = GlanceModifier.defaultWeight(),
+        )
+        IconButton(
+            resId = R.drawable.ic_widget_refresh,
+            contentDescription = context.getString(R.string.widget_refresh),
+            onClick = GlanceModifier.clickable(actionRunCallback<RefreshAgendaAction>()),
+        )
+        IconButton(
+            resId = R.drawable.ic_widget_add,
+            contentDescription = context.getString(R.string.widget_new_event),
+            onClick = GlanceModifier.clickable(
+                actionStartActivity(
+                    MainActivity.openCreateIntent(context, today(systemZone())),
+                ),
+            ),
+        )
+    }
+}
+
+@Composable
+private fun IconButton(resId: Int, contentDescription: String, onClick: GlanceModifier) {
+    Box(
+        modifier = GlanceModifier.size(40.dp).then(onClick),
+        contentAlignment = Alignment.Center,
+    ) {
+        Image(
+            provider = ImageProvider(resId),
+            contentDescription = contentDescription,
+            colorFilter = ColorFilter.tint(GlanceTheme.colors.onSurfaceVariant),
+            modifier = GlanceModifier.size(22.dp),
+        )
+    }
+}
+
+@Composable
+private fun DayHeaderRow(date: LocalDate, today: LocalDate) {
+    val context = androidx.glance.LocalContext.current
+    Text(
+        text = agendaDayLabel(context, date, today),
+        style = TextStyle(
+            color = if (date == today) GlanceTheme.colors.primary
+            else GlanceTheme.colors.onSurfaceVariant,
+            fontSize = 13.sp,
+            fontWeight = FontWeight.Medium,
+        ),
+        modifier = GlanceModifier
+            .fillMaxWidth()
+            .padding(start = 8.dp, end = 8.dp, top = 10.dp, bottom = 4.dp)
+            .clickable(actionStartActivity(MainActivity.openDateIntent(context, date))),
+    )
+}
+
+@Composable
+private fun EventRow(event: EventInstance, dark: Boolean) {
+    val context = androidx.glance.LocalContext.current
+    val title = event.title.ifBlank { context.getString(R.string.event_untitled) }
+    Row(
+        modifier = GlanceModifier
+            .fillMaxWidth()
+            .padding(horizontal = 4.dp, vertical = 4.dp)
+            .clickable(
+                actionStartActivity(
+                    MainActivity.eventDetailIntent(
+                        context = context,
+                        eventId = event.eventId,
+                        beginMillis = event.start.toEpochMilliseconds(),
+                        endMillis = event.end.toEpochMilliseconds(),
+                    ),
+                ),
+            ),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Box(
+            modifier = GlanceModifier
+                .width(5.dp)
+                .height(36.dp)
+                .cornerRadius(3.dp)
+                .background(pastelize(event.color, dark)),
+        ) {}
+        Spacer(GlanceModifier.width(10.dp))
+        Column(modifier = GlanceModifier.defaultWeight()) {
+            Text(
+                text = title,
+                maxLines = 1,
+                style = TextStyle(color = GlanceTheme.colors.onSurface, fontSize = 14.sp),
+            )
+            Text(
+                text = eventTimeSummary(context, event),
+                maxLines = 1,
+                style = TextStyle(color = GlanceTheme.colors.onSurfaceVariant, fontSize = 12.sp),
+            )
+        }
+    }
+}
+
+@Composable
+private fun WidgetMessage(resId: Int) {
+    val context = androidx.glance.LocalContext.current
+    Box(
+        modifier = GlanceModifier.fillMaxSize().padding(16.dp),
+        contentAlignment = Alignment.Center,
+    ) {
+        Text(
+            text = context.getString(resId),
+            style = TextStyle(color = GlanceTheme.colors.onSurfaceVariant, fontSize = 14.sp),
+        )
+    }
+}
+
+private fun zone(): TimeZone = systemZone()
+
+/** "Today · Wed, 17 Jun" — relative word for today/tomorrow, else the date. */
+private fun agendaDayLabel(context: Context, date: LocalDate, today: LocalDate): String {
+    val relative = when (date) {
+        today -> context.getString(R.string.agenda_header_today)
+        today.plus(1, DateTimeUnit.DAY) -> context.getString(R.string.agenda_header_tomorrow)
+        else -> null
+    }
+    val locale = Locale.getDefault()
+    val java = java.time.LocalDate.of(date.year, date.month.ordinal + 1, date.day)
+    val weekday = java.dayOfWeek.getDisplayName(JavaTextStyle.SHORT, locale)
+    val monthName = java.month.getDisplayName(JavaTextStyle.SHORT, locale)
+    val formatted = "$weekday, ${date.day} $monthName"
+    return if (relative != null) "$relative · $formatted" else formatted
+}
+
+private fun eventTimeSummary(context: Context, event: EventInstance): String {
+    val time = if (event.isAllDay) {
+        context.getString(R.string.event_detail_all_day)
+    } else {
+        "${formatTime(event.start)} – ${formatTime(event.end)}"
+    }
+    val location = event.location?.takeIf { it.isNotBlank() }
+    return if (location != null) "$time · $location" else time
+}
+
+private fun formatTime(instant: Instant): String {
+    val t = instant.toLocalDateTime(zone()).time
+    return "%02d:%02d".format(t.hour, t.minute)
+}

app/src/main/java/de/jeanlucmakiola/calendula/widget/agenda/AgendaWidgetReceiver.kt

@@ -0,0 +1,13 @@
+package de.jeanlucmakiola.calendula.widget.agenda
+
+import androidx.glance.appwidget.GlanceAppWidget
+import androidx.glance.appwidget.GlanceAppWidgetReceiver
+
+/**
+ * Host-facing receiver for the agenda widget. Declared in the manifest with the
+ * `appwidget_info_agenda` provider metadata; delegates all rendering to
+ * [AgendaWidget].
+ */
+class AgendaWidgetReceiver : GlanceAppWidgetReceiver() {
+    override val glanceAppWidget: GlanceAppWidget = AgendaWidget()
+}