What problem does it solve? UI animation code often ships with subtle craft defects — sluggish easing, wrong transform origins, non-GPU properties, missing reduced-motion handling — that make interfaces feel slow or jarring even when they technically work. This Skill provides a rigorous, opinionated review of animation and motion code so these issues are caught before merge. ## Core Features & Use Cases - Standards-based review: Evaluates every animation against ten non-negotiable rules covering justified motion, frequency-appropriateness, easing, sub-300ms durations, origin correctness, interruptibility, GPU-only properties, accessibility, asymmetric timing, and cohesion. - Precise citations: Pulls exact easing curves, duration tables, spring configs, and gesture thresholds from a bundled standards reference (STANDARDS.md) instead of approximating values. - Structured verdicts: Produces a Before/After/Why findings table plus a tiered verdict ending in an explicit Block or Approve decision. - Use Case: A developer opens a pull request adding a dropdown that animates with transition: all 400ms ease-in from scale(0). The review flags the unbounded transition, the ease-in curve, the over-budget duration, and the wrong origin, then prescribes transform/opacity-only properties, a strong ease-out cubic-bezier, and scaling from the trigger element. ## Quick Start Review the animation and motion code in this pull request and give me a findings table with a block or approve verdict.
