What problem does it solve? Web interfaces often feel stiff because animations are pre-scripted, non-interruptible, and disconnected from user input. This Skill translates Apple's WWDC design guidance (Designing Fluid Interfaces, UI Typography, Audio-Haptic design) into concrete web techniques so gesture-driven UI feels physical, responsive, and alive. ## Core Features & Use Cases - Spring-based motion design: Concrete damping/response values for moves, rotations, and sheets, mapped to Motion/Framer Motion APIs, with velocity handoff and momentum projection formulas. - Gesture engineering: Pointer Events patterns for 1:1 drag tracking, interruptible animations, rubber-banding at boundaries, and momentum projection using Apple's exponential decay function. - Materials, typography, and accessibility: backdrop-filter translucency hierarchies, size-specific tracking/leading rules, and reduced-motion/reduced-transparency fallbacks. - Use Case: When building a bottom sheet that users can drag, flick, and re-grab mid-animation, use this Skill to implement velocity-aware springs that project the resting point and settle without visible seams. ## Quick Start Review my drag-to-dismiss sheet component and rewrite its animation to use interruptible springs with velocity handoff following Apple design principles.
