UI Animation

• IS: designing, implementing, reviewing, debugging UI motion (springs, gestures, drag, easing, CSS transitions, keyframes, Motion), sweeping an interface for the moments that would genuinely benefit from motion, measuring motion from a recording (extract frames, track, fit curves) to emit code plus a handoff spec, naming a described motion effect (reverse-lookup vocabulary), and gating sparse interface sound.
• IS NOT: choosing overall visual direction, palettes, or typography (use ui-design Direction mode), auditing a whole page's UI quality (use ui-design Audit mode), or named text-effect specs (use the external animate-text skill where installed).

Routing boundary

product-design owns action semantics, scope, reversibility, and contested state choices. ui-design builds and styles those states. ui-animation owns timing, gestures, and measured motion. A routine missing loading or error state stays with the UI build; a gesture replacing a control needs a product decision and an accessible alternative before its physics.

Reference files