PRODUCT.md records the durable constraints the UI work keeps having to
rediscover: dark-first is binding (night reading), mobile is the target
rather than the starting breakpoint, and updated_at ordering is a
correctness rule the design must not decorate over.
The two critique snapshots are the scored before/after (21/40, then
26/40) the card fixes were driven from — worth keeping as the record of
which problems were already known, and which ones the fixes introduced.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>