Tailwind v4 does not derive --radius-xs through --radius-3xl from --radius. The named scale is independent, so Cards (rounded-xl), Buttons (rounded-md), etc. retained non-zero border-radius despite --radius: 0. Adding all scale tokens as 0 ensures complete sharp-corner cascade. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>