What problem does it solve? Web interfaces often feel static and disconnected because animations are pre-scripted, gestures lack momentum, and motion cannot be interrupted mid-flight. This Skill translates Apple's WWDC design guidance into concrete web techniques so interfaces respond instantly, track gestures 1:1, and animate with physical realism. ## Core Features & Use Cases - Spring-Based Motion: Replaces fixed-duration CSS transitions with interruptible, velocity-aware springs using damping ratio and response parameters, mapped to Motion/Framer Motion APIs. - Gesture Engineering: Covers pointer capture, velocity handoff, momentum projection, rubber-banding, and 1:1 drag tracking for sheets, drawers, and carousels. - Materials, Typography & Accessibility: Provides guidance on backdrop-filter translucency, optical sizing and tracking, and reduced-motion/reduced-transparency fallbacks. - Use Case: When building a bottom sheet that users can drag, flick, and re-grab mid-animation, apply the velocity handoff and momentum projection formulas so the sheet lands naturally at the nearest snap point. ## Quick Start Ask the AI to review or build a gesture-driven UI component, such as a draggable bottom sheet with spring physics, following Apple fluid interface principles.
