Tailwind CSS & shadcn/ui Design System

Overview

Expert guide for creating and managing a centralized Design System using Tailwind CSS (v4.1+) and shadcn/ui. This skill provides structured workflows for defining design tokens, configuring themes with CSS variables, and building a consistent UI component library based on shadcn/ui primitives.

Relationship with other skills:

• tailwind-css-patterns covers utility-first styling, responsive design, and general Tailwind CSS usage
• shadcn-ui covers individual component installation, configuration, and implementation
• This skill focuses on the system-level orchestration: design tokens, theming infrastructure, component wrapping patterns, and ensuring consistency across the entire application

When to Use

• Setting up a new design system from scratch with Tailwind CSS and shadcn/ui
• Defining design tokens (colors, typography, spacing, radius, shadows) as CSS variables
• Configuring globals.css with a centralized theming system (light/dark mode)
• Wrapping shadcn/ui components into design system primitives with enforced constraints
• Building a token-driven component library for consistent UI
• Migrating from a JavaScript-based Tailwind config to CSS-first configuration (v4.1+)
• Establishing color palettes with oklch format for perceptual uniformity
• Creating multi-theme support beyond light/dark (e.g., brand themes)

Instructions

Step 1: Initialize Design System Configuration

1. Assess the project: Check if Tailwind CSS and shadcn/ui are already installed
2. Create the globals.css: Set up the central CSS file with design tokens
3. Configure Tailwind: Use the @theme directive (v4.1+) or tailwind.config.js (v3)
4. Install shadcn/ui: Initialize with the CLI and configure the theme

Step 2: Define Design Tokens

Design tokens are the foundation. Define them as CSS custom properties in globals.css:

• Colors: Brand palette, semantic colors, surface colors
• Typography: Font families, sizes, weights, line heights
• Spacing: Consistent spacing scale
• Borders: Radius, widths
• Shadows: Elevation levels
• Animations: Transition durations and easing functions

Step 3: Configure Theming Infrastructure

Set up light/dark mode support and expose tokens to Tailwind via @theme inline.

Step 4: Wrap shadcn/ui Components

Create design system primitives that enforce token usage and provide consistent API.

Step 5: Document and Validate

Create a living style guide and validate token usage across the codebase.

Examples

Complete globals.css with Design Tokens

See references/globals.css.example for a complete, production-ready globals.css with all design tokens configured.

Quick example for adding custom tokens:

:root {
  --warning: oklch(0.84 0.16 84);
  --warning-foreground: oklch(0.28 0.07 46);
}

.dark {
  --warning: oklch(0.41 0.11 46);
  --warning-foreground: oklch(0.99 0.02 95);
}

@theme inline {
  --color-warning: var(--warning);
  --color-warning-foreground: var(--warning-foreground);
}

Usage: <div className="bg-warning text-warning-foreground">Warning</div>

Wrapping shadcn/ui Components as Design System Primitives

Create constrained design system components that enforce token usage. See references/component-wrapping.md for complete examples including Button, Text, and Stack primitives.

Quick example:

import { Button as ShadcnButton } from "@/components/ui/button";

export function Button({ variant = "primary", size = "md", ...props }) {
  const variantMap = { primary: "default", secondary: "secondary" };
  const sizeMap = { sm: "sm", md: "default", lg: "lg" };
  return (
    <ShadcnButton
      variant={variantMap[variant]}
      size={sizeMap[size]}
      {...props}
    />
  );
}

Multi-Theme Support

For applications requiring multiple brand themes beyond light/dark:

[data-theme="ocean"] {
  --primary: oklch(0.55 0.18 230);
  --primary-foreground: oklch(0.985 0 0);
}

[data-theme="forest"] {
  --primary: oklch(0.50 0.15 145);
  --primary-foreground: oklch(0.985 0 0);
}

const [theme, setTheme] = useState("light");
useEffect(() => {
  document.documentElement.setAttribute("data-theme", theme);
}, [theme]);

Design Token Validation

Verify all required tokens are defined:

#!/bin/bash
REQUIRED=("--background" "--foreground" "--primary" "--primary-foreground")
for token in "${REQUIRED[@]}"; do
  grep -q "$token:" src/styles/globals.css || echo "Missing: $token"
done

Constraints and Warnings

• oklch color format: Use oklch for perceptual uniformity. Not all browsers support oklch natively; check compatibility if targeting older browsers
• Token naming: Follow the shadcn/ui convention (--primary, --primary-foreground) for seamless integration
• @theme inline vs @theme: Use @theme inline when bridging CSS variables to Tailwind utilities; use @theme for direct token definition
• Component wrapping: Keep wrapper components thin. Only add constraints that enforce design system rules; avoid duplicating shadcn/ui logic
• Dark mode: Always define dark mode values for every token in :root. Missing dark tokens cause visual regressions
• CSS variable scoping: Tokens defined in :root are global. Use [data-theme] selectors for multi-theme without conflicts
• Performance: Avoid excessive CSS custom property chains. Each var() lookup adds minimal but non-zero overhead
• Tailwind v4 vs v3: The @theme directive and @theme inline are v4.1+ features. For v3 projects, use tailwind.config.js with theme.extend

Best Practices

1. Single source of truth: All design tokens live in globals.css. Never hardcode color values in components
2. Semantic naming: Use purpose-based names (--primary, --destructive) not appearance-based (--blue-500, --red-600)
3. Foreground pairing: Every background token must have a matching -foreground token for contrast compliance
4. Token scale: Define a complete scale for custom palettes (50-950) to provide flexibility
5. Component barrel exports: Export all DS components from a single index.ts for clean imports
6. Accessibility: Ensure all token pairs (background/foreground) meet WCAG AA contrast (4.5:1 for text, 3:1 for large text)
7. Document tokens: Maintain a visual reference of all tokens for the team
8. Consistent spacing: Use Tailwind's spacing scale (gap-2, gap-4, gap-6) through DS components rather than arbitrary values

References

• Tailwind CSS v4 Theme Configuration: https://tailwindcss.com/docs/theme
• Tailwind CSS Functions and Directives: https://tailwindcss.com/docs/functions-and-directives
• shadcn/ui Theming Guide: https://ui.shadcn.com/docs/theming
• shadcn/ui Installation (Manual): https://ui.shadcn.com/docs/installation/manual
• oklch Color Space: https://oklch.com