- New theme.yml keys: nav-link, nav-link-active, nav-section-heading (per
light/dark mode). Fixes themes where nav-background equals accent, which
made active nav links invisible against their own background.
- New colours-semantic-dark block overrides callout semantic colours in dark
mode only, preventing washed-out callout borders and backgrounds on dark
page backgrounds.
- CSS: nav item and section heading selectors now use the new CSS variables
with graceful fallbacks to existing defaults — no breakage for themes that
don't set the new keys.
- app/theme.yml starter updated with new keys (commented examples) and
sensible colours-semantic-dark defaults.
- CLAUDE.md updated with full key reference table and guidance on when to
use nav colour overrides.
- docs/claude-design.md: new authoring guide for Claude Design covering
contrast rules, nav pattern examples, and a pre-publish checklist.
https://claude.ai/code/session_01NQKywehSj8Ku4yKhwB4VNB
