react-ui

# UI Skills Opinionated constraints for building better interfaces with agents. ## Stack - MUST use Tailwind CSS defaults (spacing, radius, shadows) before custom values - MUST use `motion/react` (formerly `framer-motion`) when JavaScript animation is required - SHOULD use `tw-animate-css` for entrance and micro-animations in Tailwind CSS - MUST use `cn` utility (`clsx` + `tailwind-merge`) for class logic ## Components - SHOULD prefer [`shadcn/ui`](https://ui.shadcn.com) components when available in the project - SHOULD add new `shadcn/ui` components via CLI (`npx shadcn@latest add <component>`) when needed - MUST use the project's existing component primitives first - MUST use accessible component primitives for anything with keyboard or focus behavior (`shadcn/ui`, `Radix`, `React Aria`, `Base UI`) - NEVER mix primitive systems within the same interaction surface - MUST add an `aria-label` to icon-only buttons - NEVER rebuild keyboard or focus behavior by hand unless explicitly requested ## Interaction - MUST use an `AlertDialog` for destructive or irreversible actions - SHOULD use structural skeletons for loading states - NEVER use `h-screen`, use `h-dvh` - MUST respect `safe-area-inset` for fixed elements - MUST show errors next to where the action happens - NEVER block paste in `input` or `textarea` elements ## Animation - NEVER add animation unless it is explicitly requested - MUST animate only compositor props (`transform`, `opacity`) - NEVER animate layout properties (`width`, `height`, `top`, `left`, `margin`, `padding`) - SHOULD avoid animating paint properties (`background`, `color`) except for small, local UI (text, icons) - SHOULD use `ease-out` on entrance - NEVER exceed `200ms` for interaction feedback - MUST pause looping animations when off-screen - MUST respect `prefers-reduced-motion` - NEVER introduce custom easing curves unless explicitly requested - SHOULD avoid animating large images or full-screen surfaces ## Typography - MUST use `text-balance` for headings and `text-pretty` for body/paragraphs - MUST use `tabular-nums` for data - SHOULD use `truncate` or `line-clamp` for dense UI - NEVER modify `letter-spacing` (`tracking-`) unless explicitly requested ## Layout - MUST use a fixed `z-index` scale (no arbitrary `z-x`) - SHOULD use `size-x` for square elements instead of `w-x` + `h-x` ## Performance - NEVER animate large `blur()` or `backdrop-filter` surfaces - NEVER apply `will-change` outside an active animation - NEVER use `useEffect` for anything that can be expressed as render logic ## Design - NEVER use gradients unless explicitly requested - NEVER use purple or multicolor gradients - NEVER use glow effects as primary affordances - SHOULD use Tailwind CSS default shadow scale unless explicitly requested - MUST give empty states one clear next action - SHOULD limit accent color usage to one per view - SHOULD use existing theme or Tailwind CSS color tokens before introducing new ones