style(web): extract design system tokens + DESIGN.md
DESIGN.md: 7-section design system (palette, typography, spacing,
motion, components, sections, banned patterns). Documents existing
dark + cyan brand to enforce 'evolution not revolution'.
globals.css: add design tokens — --surface-{0..3}, --text-{primary,
secondary,tertiary}, --accent-primary{,-soft,-border}, --border-
{default,subtle}, status tokens (success/warning/danger/info).
Add .reveal-on-enter utility: opacity 0 → 1, translateY(8px) → 0
over 600ms cubic-bezier(0.16, 1, 0.3, 1). Triggered via
'data-revealed' attribute set by IntersectionObserver upstream.
Respects 'prefers-reduced-motion: reduce' — falls back to instant
opacity transition.
Add .ring-cyan focus utility consolidating focus-visible rings
across components (was ad-hoc per-component).
YeonGyu-Kim
78ca837e82