Code review — repo best practices

Run through this checklist on any diff. Flag violations with the specific line and the suggested fix.

Tailwind

• Prefer utilities over custom classes. If a pattern can be expressed with existing Tailwind utilities, use them. Don't add a custom class in app/globals.css unless the pattern repeats 3+ times with the same composition.
• Use the @theme tokens (bg-surface, text-ink, border-line, etc.) — never hardcode hex in JSX.
• No style={{ ... }} unless the value is dynamic (e.g. width: ${pct}%). Static styling belongs in className.
• No @apply in globals.css (Tailwind 4 best practice — put the utilities on the element instead, or extract a React component).

Constants + utils

• Magic numbers → lib/constants/ (e.g. SCORE_THRESHOLD_GOOD, LEADERBOARD_PAGE_SIZE).
• Repeated formatting → lib/utils/format.ts (compactStars, relativeTime, hostLabel).
• Repeated scoring logic → lib/utils/score.ts (scoreTier, TIER_TEXT_CLASS, TIER_BG_CLASS).
• A helper that's used once doesn't belong in utils/; inline it.

I/O boundary (architecturally important)