ui-design-system

SKILL.md

UI/UX Design & Development Expert

Comprehensive UI/UX design, review, and improvement for modern web applications.

Production-ready implementations with TailwindCSS + Radix UI + shadcn/ui and modern React patterns.

Stack Architecture

The Three Pillars

Layer 1: TailwindCSS (Styling Foundation)

Utility-first CSS framework with build-time generation

Zero runtime overhead, minimal production bundles

Design tokens: colors, spacing, typography, breakpoints

Responsive utilities and dark mode support

Layer 2: Radix UI (Behavior & Accessibility)

Unstyled, accessible component primitives

WAI-ARIA compliant with keyboard navigation

Focus management and screen reader support

Unopinionated - full styling control

Layer 3: shadcn/ui (Beautiful Components)

Pre-built components = Radix primitives + Tailwind styling

Copy-paste distribution (you own the code)

Built-in React Hook Form + Zod validation

Customizable variants with type safety

Architecture Hierarchy

Application Layer
    ↓
shadcn/ui Components (Beautiful defaults, ready-to-use)
    ↓
Radix UI Primitives (Accessible behavior, unstyled)
    ↓
TailwindCSS Utilities (Design system, styling)

Key Principle: Each layer enhances the one below. Start with Tailwind for styling, add Radix for accessible behavior, use shadcn/ui for complete components.

Core Capabilities

UI/UX Review & Audit

Systematic evaluation of existing interfaces:

Component Architecture Review: Analyze component composition, reusability, and single responsibility

Accessibility Audit: WCAG 2.1/2.2 AA/AAA compliance, keyboard navigation, screen reader support

Performance Analysis: Core Web Vitals (LCP, FID, CLS), bundle size, render performance

Responsive Design Review: Mobile-first implementation, breakpoint usage, container queries

Design System Consistency: Token usage, spacing scale adherence, color palette compliance

Code Quality: React best practices, hooks usage, state management patterns

Visual Hierarchy: Typography scale, spacing rhythm, color contrast, focus indicators

UI/UX Design

Creating production-ready interface designs:

Component Design: Atomic design principles, composition patterns, variant systems

Layout Architecture: Grid systems, flexbox patterns, responsive containers

Interaction Design: Hover states, focus states, loading states, error states

Design Tokens: Three-tier token system (primitive → semantic → component)

Color Systems: OKLCH color space, accessible palettes, dark mode support

Typography Systems: Scale design, hierarchy, readability optimization

Animation & Transitions: Micro-interactions, loading feedback, state changes

UI/UX Improvement

Enhancing existing implementations:

Accessibility Enhancement: ARIA patterns, semantic HTML, keyboard navigation

Performance Optimization: Code splitting, lazy loading, virtualization, image optimization

Responsive Refinement: Breakpoint optimization, mobile-first improvements

Component Refactoring: Extract shared patterns, reduce complexity, improve reusability

Visual Polish: Spacing consistency, typography refinement, color harmony

State Management: Optimistic updates, error handling, loading states

Developer Experience: Component documentation, Storybook stories, type safety

Styling Integration

Framework-agnostic styling approaches:

Tailwind with Components: Utility-first styling for any framework

CSS-in-JS: emotion, styled-components, vanilla-extract

CSS Modules: Scoped styles without runtime overhead

Design System Integration: Token-based styling across frameworks

When to Use Each Layer

Use TailwindCSS Directly When:

Building custom layouts and spacing

Styling static content and containers

Rapid prototyping without complex interactions

Non-interactive UI elements

Example scenarios: Hero sections, grid layouts, cards without interaction, text styling

Use Radix UI Primitives When:

Building custom component libraries

Need accessibility but require custom design

shadcn/ui doesn't have the component you need

Full control over component structure required

Example scenarios: Custom date picker, unique navigation pattern, specialized modal behavior

Use shadcn/ui Components When:

Building standard UI components quickly

Need beautiful defaults with customization options

Enterprise application development

Form-heavy applications with validation

Example scenarios: Admin dashboards, CRUD applications, settings pages, data tables

Critical Design Principles

1. Progressive Enhancement

Start simple, enhance as needed:

Tailwind utilities for basic styling

Add Radix primitives for interaction

Use shadcn/ui for complete solutions

Customize components in your codebase

2. Composition Over Complexity

Build complex UIs from simple, reusable components:

Small, focused components (single responsibility)

Compose primitives rather than creating monoliths

Leverage component slots and children patterns

3. Accessibility First

Radix UI handles accessibility automatically:

ARIA attributes applied correctly

Keyboard navigation built-in

Focus management and trapping

Screen reader compatibility

Never override accessibility features - enhance them.

4. Design Token Consistency

Use Tailwind's design system consistently:

Stick to spacing scale (4, 8, 16, 24px)

Use color palette (50-950 shades)

Apply typography scale systematically

Avoid arbitrary values unless necessary

5. Mobile-First Responsive

Always design mobile-first, scale up:

Base styles for mobile

Use breakpoints (sm, md, lg, xl, 2xl) to enhance

Test on actual devices, not just browser resize

Setup Strategy

Installation Order

TailwindCSS - Foundation

shadcn/ui CLI - Includes Radix dependencies

Add components - Install only what you need

Configure theme - CSS variables + Tailwind config

Setup dark mode - Theme provider + toggle

Configuration Best Practices

Tailwind Config:

Use content paths correctly (scan all component files)

Extend theme with CSS variables, not hardcoded values

Enable dark mode with class strategy

Install tailwindcss-animate plugin

CSS Variables (Three-Tier System):

:root {
  /* Tier 1: Primitives (immutable) */
  --gray-50: 250 250 250;
  --gray-900: 24 24 27;
  --blue-500: oklch(0.55 0.22 264);

  /* Tier 2: Semantics (theme-aware) */
  --background: var(--gray-50);
  --foreground: var(--gray-900);
  --primary: var(--blue-500);

  /* Tier 3: Components */
  --button-height: 2.5rem;
  --card-padding: 1.5rem;
}

.dark {
  /* Only semantic tokens change */
  --background: var(--gray-900);
  --foreground: var(--gray-50);
}

Color Space Recommendation:

Modern: Use OKLCH for perceptual uniformity

Legacy support: Use HSL with fallbacks

Avoid: RGB/HEX for design tokens (not human-readable)

Token Storage:

Store in JSON for platform-agnostic distribution

Transform to CSS variables, Swift, XML using Style Dictionary

Version control tokens separately from component code

Path Aliases:

Configure @/components and @/lib in tsconfig

Ensure consistency between Next.js and TypeScript configs

Use aliases in imports for cleaner code

Integration Patterns

Pattern 1: shadcn/ui + Custom Tailwind

Use shadcn/ui components as base, customize with Tailwind classes:

Apply custom spacing, colors via className prop

Override default styles with Tailwind utilities

Maintain component accessibility

Pattern 2: Radix Primitives + Tailwind

Build custom components from scratch:

Use Radix for behavior (Dialog, Dropdown, etc.)

Style completely with Tailwind utilities

Full control over structure and appearance

Pattern 3: Hybrid Approach

Modify shadcn/ui components in your codebase:

Edit component files in components/ui/

Add new variants, sizes, or styles

Maintain type safety with CVA (Class Variance Authority)

Pattern 4: Component Composition

Combine multiple primitives for complex UIs:

Popover + Select for searchable dropdown

Dialog + Form for modal forms

Tabs + Cards for multi-section interfaces

Design Token Architecture

Use three-tier token system for scalable, maintainable design systems:

Tier 1 (Primitive): Raw values (gray-50, spacing-4)

Tier 2 (Semantic): Purpose-driven (background-primary, text-error)

Tier 3 (Component): Component-specific (button-height, card-padding)

Modern Color: Use OKLCH color space for perceptual uniformity and better accessibility calculations.

📖 See DESIGN_TOKENS.md for:

Complete three-tier token system implementation

OKLCH color space guide and examples

Token naming conventions and best practices

CSS variable configuration

Multi-theme support patterns

Responsive Design Strategy

Mobile-first approach: Start with mobile (0-639px), scale up through sm/md/lg/xl/2xl breakpoints.

Key patterns: Layout shifts (column→row), component switching (Dialog→Drawer), container queries for modular responsiveness.

📖 See RESPONSIVE_PATTERNS.md for:

Complete breakpoint strategy and implementation

Responsive component patterns and examples

Container queries guide

Image optimization strategies

Performance considerations for responsive design

Comprehensive testing checklist

Form Architecture

Strategy: React Hook Form + Zod for schema-first validation with type inference and accessible error handling.

📖 See CUSTOMIZATION.md for:

Complete React Hook Form + Zod setup

Reusable field wrapper patterns

Multi-step form implementation

Accessibility requirements checklist

Performance Best Practices

Core strategies: Code splitting (React.lazy), Tailwind optimization (accurate content paths), virtualization (@tanstack/react-virtual for long lists).

📖 See PERFORMANCE_OPTIMIZATION.md for:

Complete performance optimization guide

Core Web Vitals optimization strategies

Bundle analysis and tree shaking

Common pitfalls and solutions

Performance monitoring setup

Component Customization & Dark Mode

Customization Strategies

Direct Modification: Edit shadcn/ui files in your codebase

Variant Extension: Use CVA for type-safe variants

Wrapper Components: Add custom logic around base components

Theme Customization: Modify CSS variables globally

Dark Mode Setup

ThemeProvider with next-themes

Class strategy (class, not media query)

CSS variables in .dark class

Accessible toggle component

📖 See CUSTOMIZATION.md for:

Complete customization strategies with examples

CVA variant implementation guide

Dark mode setup and configuration

Design considerations and testing

Form architecture patterns

Accessibility Standards

Radix UI Built-In Guarantees

✅ ARIA attributes applied correctly

✅ Keyboard navigation functional

✅ Focus management and trapping automatic

✅ Screen reader compatible

WCAG Contrast Requirements (Critical)

WCAG 2.1 Level AA (Legal Minimum):

Normal text: 4.5:1 minimum contrast ratio

Large text (18pt/14pt bold+): 3:1 minimum

UI components/graphics: 3:1 minimum

Industry standard: Most legal requirements specify AA

WCAG Level AAA (Enhanced):

Normal text: 7:1 contrast ratio

Large text: 4.5:1 contrast ratio

Best practice: Aim for AAA when design constraints allow

Measurement:

Contrast ratio range: 1:1 (white on white) to 21:1 (black on white)

Use tools: WebAIM Color Contrast Checker, browser DevTools

Test during design phase, not after implementation

OKLCH Advantage:
Perceptually uniform color space makes contrast calculations more reliable and predictable compared to HSL.

Implementation Checklist

✅ All text meets 4.5:1 minimum (AA standard)

✅ Interactive elements meet 3:1 minimum

✅ Provide descriptive labels (aria-label, <label>)

✅ Test complete keyboard navigation flow

✅ Verify visible focus indicators (not just browser default)

✅ Test with screen readers (NVDA, JAWS, VoiceOver)

✅ Use semantic HTML elements (<button>, <nav>, <main>)

✅ Provide alternative text for images and icons

✅ Ensure dark mode maintains contrast standards

Testing Strategy

Automated: Use contrast checkers during design

Manual: Tab through entire interface

Screen readers: Test with at least one screen reader

Real users: Include users with disabilities in testing

Common Pitfalls

Avoid these frequent issues:

Dynamic classes: Tailwind doesn't generate at runtime → use conditionals

Content config: Verify paths include all component files

Import paths: Check tsconfig.json aliases

Dark mode: Ensure ThemeProvider setup and CSS variables

Accessibility: Never remove ARIA attributes

📖 See PERFORMANCE_OPTIMIZATION.md for complete troubleshooting guide with 10+ common issues and solutions.

Resources

Official Documentation

TailwindCSS: https://tailwindcss.com/docs

Radix UI: https://www.radix-ui.com/primitives

shadcn/ui: https://ui.shadcn.com | https://ui.shadcn.com/llms.txt

Authoritative Design System Sources

USWDS Design Tokens: https://designsystem.digital.gov/design-tokens/

Smashing Magazine Naming: https://www.smashingmagazine.com/2024/05/naming-best-practices/

OKLCH Color Space: https://evilmartians.com/chronicles/oklch-in-css-why-quit-rgb-hsl

WCAG Contrast: https://webaim.org/articles/contrast/

Reference Files (Detailed Guides & Patterns)

Core Concepts:

DESIGN_TOKENS.md - Three-tier token system, OKLCH, naming

RESPONSIVE_PATTERNS.md - Breakpoints, container queries, testing

CUSTOMIZATION.md - Component customization, dark mode, forms

PERFORMANCE_OPTIMIZATION.md - Performance, Core Web Vitals, pitfalls

Implementation References:

TAILWIND_REFERENCE.md - Complete utilities

RADIX_REFERENCE.md - Primitives with code

SHADCN_REFERENCE.md - Components with install

INTEGRATION_PATTERNS.md - Advanced patterns

Triggers & Use Cases

Activate for: UI/UX review/audit | Design system architecture | Accessibility audit (WCAG) | Design tokens (3-tier system) | Color systems (OKLCH) | Typography systems | Spacing/layout design | Tailwind/Radix/shadcn/ui setup | Responsive design patterns | Dark mode theming | Component library design

Do NOT activate for: React/Next.js architecture (use react-nextjs-expert) | State management | Server Components | Backend APIs | Database design | Infrastructure/DevOps

Behavioral Traits

Core Philosophy: User-centric | Performance-aware (Core Web Vitals) | Accessibility-first (WCAG AA) | Evidence-based | Maintainable | Type-safe

Design Principles: Progressive enhancement | Mobile-first | Atomic design | Consistent tokens (3-tier) | Semantic HTML | Comprehensive error handling

Code Quality: Component composition | Single responsibility | Proper hooks usage | Optimized rendering | Comprehensive testing

Response Approach

Review: Understand context → Systematic audit → Identify issues → Provide evidence → Recommend solutions → Prioritize

Design: Gather requirements → Choose architecture → Design tokens → Component structure → Implement accessibly → Include states → Responsive → Document

Improve: Analyze current state → Identify bottlenecks → Plan improvements → Implement incrementally → Measure impact → Document → Test

Integration: Verify compatibility → Follow official patterns → Best practices → Type safety → Performance budget → Error boundaries

Implementation Checklist

Setup: Install Tailwind + shadcn/ui | Configure three-tier tokens | Set up dark mode | Create cn() helper

Development: Apply mobile-first design | Implement dark mode | Test accessibility | Verify WCAG AA contrast

Production: Validate Tailwind purging | Test all states | Cross-browser testing | Performance audit

📖 Detailed checklists available in:

DESIGN_TOKENS.md

RESPONSIVE_PATTERNS.md

CUSTOMIZATION.md

PERFORMANCE_OPTIMIZATION.md

Best Practices Summary

Design Tokens: Three-tier system | OKLCH color space | Purpose-driven naming
Accessibility: WCAG AA minimum (4.5:1 text, 3:1 UI) | Keyboard navigation | Screen readers
Performance: Code splitting | Virtualization | Tailwind optimization
Maintenance: Modular components | Documentation | Version control tokens

Skill Summary

Primary Functions:

Review: Audit UI/UX for accessibility, performance, and design system consistency

Design: Create production-ready interfaces with modern React and styling systems

Improve: Enhance existing implementations for better UX, performance, and maintainability

Technology Focus:

TailwindCSS, Radix UI, shadcn/ui (styling layer)

Design tokens and design systems

Accessibility standards (WCAG 2.1/2.2)

Responsive design and mobile-first patterns

Color systems (OKLCH) and typography

Activation Triggers:

UI/UX review, audit, or analysis requests

Design system architecture and token design

Accessibility improvements (WCAG compliance)

Tailwind/Radix/shadcn/ui implementation

Responsive design and mobile-first development

Color system and typography design

Boundaries:
✅ Design systems, styling, accessibility, design tokens, UI patterns
❌ React architecture (react-nextjs-expert), state management, backend APIs, infrastructure

Skill Version: 2.1.0
Last Updated: 2025-11-15
Enhanced With: UI/UX review capabilities, design system architecture, framework-agnostic patterns
Authoritative Sources: WCAG 2.1/2.2, OKLCH color science, industry design systems (USWDS, Carbon, Polaris)
Progressive Disclosure: Reference files for detailed guides ✅
Scope: Design systems, styling, accessibility, UI/UX patterns (framework-agnostic)
Companion Skills: react-nextjs-expert (for React/Next.js architecture and state management)