Replaces the current ~1.4k LOC stylesheet with a tiered design system:
@layer-ordered cascade, two-tier tokens, budgeted component classes,
five high-leverage macros, in-app style guide, and the "system is closed"
workflow rule (every page element comes from the catalog).
Validated by a throwaway /spike comparing Pico v2, Simple.css, and the
pure-custom design; pure-custom won on the code-feel criterion the user
weighted highest.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
