Update hex values → CSS var references, fix font (Merriweather→Tinos),
card pattern (border-brand-sand→border-line, bg-white→bg-surface),
and contrast table to remove hardcoded hex in favour of --palette-* names.
Addresses Leonie's review blocker on PR #446.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Brand colors, font name, dev port, route tree, and card pattern were
all outdated relative to layout.css and the current route structure.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>