Apple's approach to interface design and fluid, physical motion, translated for the web. Use when building or reviewing gesture-driven UI, spring animations, drag/swipe/sheet interactions, momentum and interruptible transitions, translucent materials and depth, typography (optical sizing, tracking,

Pick the right library for a given frontend task from a curated, opinionated list — numbers, OTP inputs, charts, command menus, virtualization, drag and drop, toasts, state, styling, and more. Only runs when explicitly invoked; it does not trigger on its own.

Design and implement one-click post-purchase upsells and downsells that raise average order value without hurting the main conversion rate. Use when asked to increase AOV, add an upsell, cross-sell or downsell after checkout, build a one-click upsell flow, monetize the thank-you page, or when someon