Design System Starter

Build robust, scalable design systems that ensure visual consistency and exceptional user experiences.

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Quick Start

Just describe what you need:

Create a design system for my React app with dark mode support

That's it. The skill provides tokens, components, and accessibility guidelines.

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Triggers

Trigger	Example
Create design system	"Create a design system for my app"
Design tokens	"Set up design tokens for colors and spacing"
Component architecture	"Design component structure using atomic design"
Accessibility	"Ensure WCAG 2.1 compliance for my components"
Dark mode	"Implement theming with dark mode support"

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Quick Reference

Task	Output
Design tokens	Color, typography, spacing, shadows JSON
Component structure	Atomic design hierarchy (atoms, molecules, organisms)
Theming	CSS variables or ThemeProvider setup
Accessibility	WCAG 2.1 AA compliant patterns
Documentation	Component docs with props, examples, a11y notes

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Bundled Resources

• references/component-examples.md - Complete component implementations
• templates/design-tokens-template.json - W3C design token format
• templates/component-template.tsx - React component template
• checklists/design-system-checklist.md - Design system audit checklist

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Design System Philosophy

What is a Design System?

A design system is more than a component library—it's a collection of:

• Design Tokens: Foundational design decisions (colors, spacing, typography)
• Components: Reusable UI building blocks
• Patterns: Common UX solutions and compositions
• Guidelines: Rules, principles, and best practices
• Documentation: How to use everything effectively

Core Principles

1. Consistency Over Creativity

• Predictable patterns reduce cognitive load
• Users learn once, apply everywhere
• Designers and developers speak the same language

2. Accessible by Default

• WCAG 2.1 Level AA compliance minimum
• Keyboard navigation built-in
• Screen reader support from the start

3. Scalable and Maintainable

• Design tokens enable global changes
• Component composition reduces duplication
• Versioning and deprecation strategies

4. Developer-Friendly

• Clear API contracts
• Comprehensive documentation
• Easy to integrate and customize

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Design Tokens

Design tokens are the atomic design decisions that define your system's visual language.

Token Categories

1. Color Tokens

Primitive Colors (Raw values):

{
  "color": {
    "primitive": {
      "blue": {
        "50": "#eff6ff",
        "100": "#dbeafe",
        "200": "#bfdbfe",
        "300": "#93c5fd",
        "400": "#60a5fa",
        "500": "#3b82f6",
        "600": "#2563eb",
        "700": "#1d4ed8",
        "800": "#1e40af",
        "900": "#1e3a8a",
        "950": "#172554"
      }
    }
  }
}

Semantic Colors (Contextual meaning):

{
  "color": {
    "semantic": {
      "brand": {
        "primary": "{color.primitive.blue.600}",
        "primary-hover": "{color.primitive.blue.700}",
        "primary-active": "{color.primitive.blue.800}"
      },
      "text": {
        "primary": "{color.primitive.gray.900}",
        "secondary": "{color.primitive.gray.600}",
        "tertiary": "{color.primitive.gray.500}",
        "disabled": "{color.primitive.gray.400}",
        "inverse": "{color.primitive.white}"
      },
      "background": {
        "primary": "{color.primitive.white}",
        "secondary": "{color.primitive.gray.50}",
        "tertiary": "{color.primitive.gray.100}"
      },
      "feedback": {
        "success": "{color.primitive.green.600}",
        "warning": "{color.primitive.yellow.600}",
        "error": "{color.primitive.red.600}",
        "info": "{color.primitive.blue.600}"
      }
    }
  }
}

Accessibility: Ensure color contrast ratios meet WCAG 2.1 Level AA:

• Normal text: 4.5:1 minimum
• Large text (18pt+ or 14pt+ bold): 3:1 minimum
• UI components and graphics: 3:1 minimum

2. Typography Tokens

{
  "typography": {
    "fontFamily": {
      "sans": "'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif",
      "serif": "'Georgia', 'Times New Roman', serif",
      "mono": "'Fira Code', 'Courier New', monospace"
    },
    "fontSize": {
      "xs": "0.75rem",     // 12px
      "sm": "0.875rem",    // 14px
      "base": "1rem",      // 16px
      "lg": "1.125rem",    // 18px
      "xl": "1.25rem",     // 20px
      "2xl": "1.5rem",     // 24px
      "3xl": "1.875rem",   // 30px
      "4xl": "2.25rem",    // 36px
      "5xl": "3rem"        // 48px
    },
    "fontWeight": {
      "normal": 400,
      "medium": 500,
      "semibold": 600,
      "bold": 700
    },
    "lineHeight": {
      "tight": 1.25,
      "normal": 1.5,
      "relaxed": 1.75,
      "loose": 2
    },
    "letterSpacing": {
      "tight": "-0.025em",
      "normal": "0",
      "wide": "0.025em"
    }
  }
}

3. Spacing Tokens

Scale: Use a consistent spacing scale (commonly 4px or 8px base)

{
  "spacing": {
    "0": "0",
    "1": "0.25rem",   // 4px
    "2": "0.5rem",    // 8px
    "3": "0.75rem",   // 12px
    "4": "1rem",      // 16px
    "5": "1.25rem",   // 20px
    "6": "1.5rem",    // 24px
    "8": "2rem",      // 32px
    "10": "2.5rem",   // 40px
    "12": "3rem",     // 48px
    "16": "4rem",     // 64px
    "20": "5rem",     // 80px
    "24": "6rem"      // 96px
  }
}

Component-Specific Spacing:

{
  "component": {
    "button": {
      "padding-x": "{spacing.4}",
      "padding-y": "{spacing.2}",
      "gap": "{spacing.2}"
    },
    "card": {
      "padding": "{spacing.6}",
      "gap": "{spacing.4}"
    }
  }
}

4. Border Radius Tokens

{
  "borderRadius": {
    "none": "0",
    "sm": "0.125rem",   // 2px
    "base": "0.25rem",  // 4px
    "md": "0.375rem",   // 6px
    "lg": "0.5rem",     // 8px
    "xl": "0.75rem",    // 12px
    "2xl": "1rem",      // 16px
    "full": "9999px"
  }
}

5. Shadow Tokens

{
  "shadow": {
    "xs": "0 1px 2px 0 rgba(0, 0, 0, 0.05)",
    "sm": "0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px -1px rgba(0, 0, 0, 0.1)",
    "base": "0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1)",
    "md": "0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1)",
    "lg": "0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1)",
    "xl": "0 25px 50px -12px rgba(0, 0, 0, 0.25)"
  }
}

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Component Architecture

Atomic Design Methodology

Atoms → Molecules → Organisms → Templates → Pages

Atoms (Primitive Components)

Basic building blocks that can't be broken down further.

Examples:

• Button
• Input
• Label
• Icon
• Badge
• Avatar

Button Component:

interface ButtonProps {
  variant?: 'primary' | 'secondary' | 'outline' | 'ghost';
  size?: 'sm' | 'md' | 'lg';
  disabled?: boolean;
  loading?: boolean;
  icon?: React.ReactNode;
  children: React.ReactNode;
}

See references/component-examples.md for complete Button implementation with variants, sizes, and styling patterns.

Molecules (Simple Compositions)

Groups of atoms that function together.

Examples:

• SearchBar (Input + Button)
• FormField (Label + Input + ErrorMessage)
• Card (Container + Title + Content + Actions)

FormField Molecule:

interface FormFieldProps {
  label: string;
  name: string;
  error?: string;
  hint?: string;
  required?: boolean;
  children: React.ReactNode;
}

See references/component-examples.md for FormField, Card (compound component pattern), Input with variants, Modal, and more composition examples.

Organisms (Complex Compositions)

Complex UI components made of molecules and atoms.

Examples:

• Navigation Bar
• Product Card Grid
• User Profile Section
• Modal Dialog

Templates (Page Layouts)

Page-level structures that define content placement.

Examples:

• Dashboard Layout (Sidebar + Header + Main Content)
• Marketing Page Layout (Hero + Features + Footer)
• Settings Page Layout (Tabs + Content Panels)

Pages (Specific Instances)

Actual pages with real content.

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Component API Design

Props Best Practices

1. Predictable Prop Names

// ✅ Good: Consistent naming
<Button variant="primary" size="md" />
<Input variant="outlined" size="md" />

// ❌ Bad: Inconsistent
<Button type="primary" sizeMode="md" />
<Input style="outlined" inputSize="md" />

2. Sensible Defaults

// ✅ Good: Provides defaults
interface ButtonProps {
  variant?: 'primary' | 'secondary';  // Default: primary
  size?: 'sm' | 'md' | 'lg';          // Default: md
}

// ❌ Bad: Everything required
interface ButtonProps {
  variant: 'primary' | 'secondary';
  size: 'sm' | 'md' | 'lg';
  color: string;
  padding: string;
}

3. Composition Over Configuration

// ✅ Good: Composable
<Card>
  <Card.Header>
    <Card.Title>Title</Card.Title>
  </Card.Header>
  <Card.Body>Content</Card.Body>
  <Card.Footer>Actions</Card.Footer>
</Card>

// ❌ Bad: Too many props
<Card
  title="Title"
  content="Content"
  footerContent="Actions"
  hasHeader={true}
  hasFooter={true}
/>

4. Polymorphic Components

Allow components to render as different HTML elements:

<Button as="a" href="/login">Login</Button>
<Button as="button">Click Me</Button>

See references/component-examples.md for complete polymorphic component TypeScript patterns.

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Theming and Dark Mode

Theme Structure

interface Theme {
  colors: {
    brand: {
      primary: string;
      secondary: string;
    };
    text: {
      primary: string;
      secondary: string;
    };
    background: {
      primary: string;
      secondary: string;
    };
    feedback: {
      success: string;
      warning: string;
      error: string;
      info: string;
    };
  };
  typography: {
    fontFamily: {
      sans: string;
      mono: string;
    };
    fontSize: Record<string, string>;
  };
  spacing: Record<string, string>;
  borderRadius: Record<string, string>;
  shadow: Record<string, string>;
}

Dark Mode Implementation

Approach 1: CSS Variables

:root {
  --color-bg-primary: #ffffff;
  --color-text-primary: #000000;
}

[data-theme="dark"] {
  --color-bg-primary: #1a1a1a;
  --color-text-primary: #ffffff;
}

Approach 2: Tailwind CSS Dark Mode

<div className="bg-white dark:bg-gray-900 text-gray-900 dark:text-white">
  Content
</div>

Approach 3: Styled Components ThemeProvider

const lightTheme = { background: '#fff', text: '#000' };
const darkTheme = { background: '#000', text: '#fff' };

<ThemeProvider theme={isDark ? darkTheme : lightTheme}>
  <App />
</ThemeProvider>

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Accessibility Guidelines

WCAG 2.1 Level AA Compliance

Color Contrast

• Normal text (< 18pt): 4.5:1 minimum
• Large text (≥ 18pt or ≥ 14pt bold): 3:1 minimum
• UI components: 3:1 minimum

Tools: Use contrast checkers like WebAIM Contrast Checker

Keyboard Navigation

// ✅ All interactive elements must be keyboard accessible
<button
 
  => e.key === 'Enter' && handleClick()}
>
  Click me
</button>

// ✅ Focus management
<Modal>
  <FocusTrap>
    {/* Modal content */}
  </FocusTrap>
</Modal>

ARIA Attributes

Essential ARIA patterns:

• aria-label: Provide accessible names
• aria-expanded: Communicate expanded/collapsed state
• aria-controls: Associate controls with content
• aria-live: Announce dynamic content changes

Screen Reader Support

• Use semantic HTML elements (<button>, <nav>, <main>)
• Avoid div/span soup for interactive elements
• Provide meaningful labels for all con