# Design

> UI/UX design guidelines for interactions, animation, layout, accessibility, and visual design. Use when building UI components, designing user experiences, or implementing user-facing features.

- Skill: `majiayu000/design-4` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds add majiayu000/design-4`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/design-4/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Web & Frontend
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/majiayu000/design-4

---


# Design System Guidelines

Follow Apple, Linear, and Vercel as design inspirations. Ask yourself "How would Apple, Linear, or Vercel design this?"

When designing React components, also use the [compound-components skill](../compound-components/SKILL.md) to build the components.

## Interactions

### Keyboard

- MUST: Full keyboard support per [WAI-ARIA APG](https://www.w3.org/WAI/ARIA/apg/patterns/)
- MUST: Visible focus rings (`:focus-visible`; group with `:focus-within`)
- MUST: Manage focus (trap, move, and return) per APG patterns

### Targets & Input

- MUST: Hit target >=24px (mobile >=44px). If visual <24px, expand hit area
- MUST: Mobile `<input>` font-size >=16px or set:
  ```html
  <meta
    name="viewport"
    content="width=device-width, initial-scale=1, maximum-scale=1, viewport-fit=cover"
  />
  ```
- NEVER: Disable browser zoom
- MUST: `touch-action: manipulation` to prevent double-tap zoom; set `-webkit-tap-highlight-color` to match design

### Inputs & Forms

- MUST: Hydration-safe inputs (no lost focus/value)
- NEVER: Block paste in `<input>/<textarea>`
- MUST: Loading buttons show spinner and keep original label
- MUST: Enter submits focused text input. In `<textarea>`, Cmd/Ctrl+Enter submits; Enter adds newline
- MUST: Keep submit enabled until request starts; then disable, show spinner, use idempotency key
- MUST: Don't block typing; accept free text and validate after
- MUST: Allow submitting incomplete forms to surface validation
- MUST: Errors inline next to fields; on submit, focus first error
- MUST: `autocomplete` + meaningful `name`; correct `type` and `inputmode`
- SHOULD: Disable spellcheck for emails/codes/usernames
- SHOULD: Placeholders end with ellipsis and show example pattern (eg, `+1 (123) 456-7890`, `sk-012345...`)
- MUST: Warn on unsaved changes before navigation
- MUST: Compatible with password managers & 2FA; allow pasting one-time codes
- MUST: Trim values to handle text expansion trailing spaces
- MUST: No dead zones on checkboxes/radios; label+control share one generous hit target

### State & Navigation

- MUST: URL reflects state (deep-link filters/tabs/pagination/expanded panels). Prefer libs like [nuqs](https://nuqs.dev)
- MUST: Back/Forward restores scroll
- MUST: Links are links--use `<a>/<Link>` for navigation (support Cmd/Ctrl/middle-click)

### Feedback

- SHOULD: Optimistic UI; reconcile on response; on failure show error and rollback or offer Undo
- MUST: Confirm destructive actions or provide Undo window
- MUST: Use polite `aria-live` for toasts/inline validation
- SHOULD: Ellipsis (`...`) for options that open follow-ups (eg, "Rename...")

### Touch/Drag/Scroll

- MUST: Design forgiving interactions (generous targets, clear affordances; avoid finickiness)
- MUST: Delay first tooltip in a group; subsequent peers no delay
- MUST: Intentional `overscroll-behavior: contain` in modals/drawers
- MUST: During drag, disable text selection and set `inert` on dragged element/containers
- MUST: No "dead-looking" interactive zones--if it looks clickable, it is

### Autofocus

- SHOULD: Autofocus on desktop when there's a single primary input; rarely on mobile (to avoid layout shift)

## Animation

- MUST: Honor `prefers-reduced-motion` (provide reduced variant)
- SHOULD: Prefer CSS > Web Animations API > JS libraries
- MUST: Animate compositor-friendly props (`transform`, `opacity`); avoid layout/repaint props (`top/left/width/height`)
- SHOULD: Animate only to clarify cause/effect or add deliberate delight
- SHOULD: Choose easing to match the change (size/distance/trigger)
- MUST: Animations are interruptible and input-driven (avoid autoplay)
- MUST: Correct `transform-origin` (motion starts where it "physically" should)

## Layout

- SHOULD: Optical alignment; adjust by +/-1px when perception beats geometry
- MUST: Deliberate alignment to grid/baseline/edges/optical centers--no accidental placement
- SHOULD: Balance icon/text lockups (stroke/weight/size/spacing/color)
- MUST: Verify mobile, laptop, ultra-wide (simulate ultra-wide at 50% zoom)
- MUST: Respect safe areas (use `env(safe-area-inset-*)`)
- MUST: Avoid unwanted scrollbars; fix overflows

## Content & Accessibility

- SHOULD: Inline help first; tooltips last resort
- MUST: Skeletons mirror final content to avoid layout shift
- MUST: `<title>` matches current context
- MUST: No dead ends; always offer next step/recovery
- MUST: Design empty/sparse/dense/error states
- SHOULD: Curly quotes (" "); avoid widows/orphans
- MUST: Tabular numbers for comparisons (`font-variant-numeric: tabular-nums` or a monospace font)
- MUST: Redundant status cues (not color-only); icons have text labels
- MUST: Don't ship the schema--visuals may omit labels but accessible names still exist
- MUST: Use the ellipsis character `...` (not `..`)
- MUST: `scroll-margin-top` on headings for anchored links; include a "Skip to content" link; hierarchical `<h1-h6>`
- MUST: Resilient to user-generated content (short/avg/very long)
- MUST: Locale-aware dates/times/numbers/currency
- MUST: Accurate names (`aria-label`), decorative elements `aria-hidden`, verify in the Accessibility Tree
- MUST: Icon-only buttons have descriptive `aria-label`
- MUST: Prefer native semantics (`button`, `a`, `label`, `table`) before ARIA
- SHOULD: Right-clicking the nav logo surfaces brand assets
- MUST: Use non-breaking spaces to glue terms: `10&nbsp;MB`, `Cmd&nbsp;+&nbsp;K`, `Vercel&nbsp;SDK`

## Visual Design

- SHOULD: Layered shadows (ambient + direct)
- SHOULD: Crisp edges via semi-transparent borders + shadows
- SHOULD: Nested radii: child <= parent; concentric
- SHOULD: Hue consistency: tint borders/shadows/text toward bg hue
- MUST: Accessible charts (color-blind-friendly palettes)
- MUST: Meet contrast--prefer [APCA](https://apcacontrast.com/) over WCAG 2
- MUST: Increase contrast on `:hover/:active/:focus`
- SHOULD: Match browser UI to bg
- SHOULD: Avoid gradient banding (use masks when needed)

## Performance (UX)

- SHOULD: Test iOS Low Power Mode and macOS Safari
- MUST: Mutations (`POST/PATCH/DELETE`) target <500 ms
- MUST: Preload only above-the-fold images; lazy-load the rest
- MUST: Prevent CLS from images (explicit dimensions or reserved space)