design-tokens

---
name: design-tokens
description: Design tokens and CSS custom properties: theme systems, dark mode, component libraries. Use when implementing design systems or user mentions tokens, CSS variables, or theming.
license: MIT
---

# Design Tokens

Design token architecture, CSS custom properties, and theme system implementation.

## When to Use This Skill

| Use this skill when... | Use another skill instead when... |
|------------------------|-----------------------------------|
| Setting up a design token system | Writing individual component styles |
| Implementing light/dark theme switching | Accessibility auditing (use accessibility skills) |
| Organizing CSS custom properties | CSS layout or responsive design |
| Integrating tokens with Tailwind/frameworks | Framework-specific component patterns |

## Core Expertise

- **Token Architecture**: Organizing design tokens for scalability
- **CSS Custom Properties**: Variable patterns and inheritance
- **Theme Systems**: Light/dark mode, user preferences
- **Component Integration**: Applying tokens consistently

## Token Structure

### Three-Tier Architecture

```css
/* 1. Primitive tokens (raw values) */
:root {
  --color-blue-50: #eff6ff;
  --color-blue-100: #dbeafe;
  --color-blue-500: #3b82f6;
  --color-blue-600: #2563eb;
  --color-blue-700: #1d4ed8;

  --spacing-1: 0.25rem;
  --spacing-2: 0.5rem;
  --spacing-4: 1rem;
  --spacing-8: 2rem;

  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
}

/* 2. Semantic tokens (purpose-based) */
:root {
  --color-primary: var(--color-blue-600);
  --color-primary-hover: var(--color-blue-700);
  --color-background: white;
  --color-surface: var(--color-gray-50);
  --color-text: var(--color-gray-900);
  --color-text-muted: var(--color-gray-600);

  --spacing-component: var(--spacing-4);
  --spacing-section: var(--spacing-8);
}

/* 3. Component tokens (specific usage) */
.button {
  --button-padding-x: var(--spacing-4);
  --button-padding-y: var(--spacing-2);
  --button-bg: var(--color-primary);
  --button-bg-hover: var(--color-primary-hover);
  --button-text: white;

  padding: var(--button-padding-y) var(--button-padding-x);
  background: var(--button-bg);
  color: var(--button-text);
}

.button:hover {
  background: var(--button-bg-hover);
}
```

### Token Categories

```css
:root {
  /* Colors */       --color-{name}-{shade}: value;
  /* Typography */   --font-family-{name}: value;
                     --font-size-{name}: value;
                     --font-weight-{name}: value;
                     --line-height-{name}: value;
  /* Spacing */      --spacing-{scale}: value;
  /* Borders */      --border-width-{name}: value;
                     --border-radius-{name}: value;
  /* Shadows */      --shadow-{name}: value;
  /* Transitions */  --duration-{name}: value;
                     --easing-{name}: value;
  /* Z-index */      --z-{name}: value;
}
```

## Theme Implementation

### Light/Dark Mode

```css
/* Default (light) theme */
:root {
  --color-background: #ffffff;
  --color-surface: #f9fafb;
  --color-text: #111827;
  --color-text-muted: #6b7280;
  --color-border: #e5e7eb;
}

/* Dark theme */
[data-theme="dark"] {
  --color-background: #111827;
  --color-surface: #1f2937;
  --color-text: #f9fafb;
  --color-text-muted: #9ca3af;
  --color-border: #374151;
}

/* System preference */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-background: #111827;
    --color-surface: #1f2937;
    --color-text: #f9fafb;
    --color-text-muted: #9ca3af;
    --color-border: #374151;
  }
}
```

## File Organization

### Recommended Structure

```
styles/
├── tokens/
│   ├── primitives.css      # Raw values
│   ├── semantic.css        # Purpose-based tokens
│   └── index.css           # Combines all tokens
├── themes/
│   ├── light.css           # Light theme overrides
│   └── dark.css            # Dark theme overrides
├── base/
│   ├── reset.css           # CSS reset
│   └── typography.css      # Base typography
└── components/
    ├── button.css
    └── card.css
```

## Component Integration

### Component-Level Tokens

```css
/* Card component with local tokens */
.card {
  --card-padding: var(--spacing-4, 1rem);
  --card-radius: var(--border-radius-lg, 0.5rem);
  --card-shadow: var(--shadow-md);
  --card-bg: var(--color-surface);
  --card-border: var(--color-border);

  padding: var(--card-padding);
  border-radius: var(--card-radius);
  box-shadow: var(--card-shadow);
  background: var(--card-bg);
  border: 1px solid var(--card-border);
}

/* Variant via token override */
.card--elevated {
  --card-shadow: var(--shadow-lg);
}

.card--outlined {
  --card-shadow: none;
  --card-border: var(--color-border-strong);
}
```

## Agentic Optimizations

| Context | Command |
|---------|---------|
| Find all CSS variables | `grep -r '--[a-z]' styles/ --include='*.css'` |
| Check token usage | `grep -r 'var(--color-primary)' src/ --include='*.css' --include='*.tsx'` |
| Find hardcoded colors | `grep -rn '#[0-9a-fA-F]\{3,8\}' src/ --include='*.css'` |
| List all token files | `find styles/tokens -name '*.css'` |
| Validate CSS syntax | `npx stylelint 'styles/**/*.css'` |

For detailed examples, advanced patterns, and best practices, see [REFERENCE.md](REFERENCE.md).

## References

- CSS Custom Properties: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_cascading_variables
- Design Tokens Format: https://design-tokens.github.io/community-group/format/
- Style Dictionary: https://styledictionary.com/
- Tailwind CSS: https://tailwindcss.com/docs/customizing-colors