Atomic Design: Quarks

Master the creation and organization of quarks - the sub-atomic design tokens and primitive values that form the foundation of your design system. Quarks are the smallest building blocks that atoms consume.

What Are Quarks?

Quarks extend Brad Frost's Atomic Design methodology by adding a level below atoms. While atoms are the smallest UI components, quarks are the smallest design values - the raw materials from which atoms are built.

Quarks are:

• Primitive Values: Colors, spacing units, font sizes, shadows
• Non-Visual: They don't render anything on their own
• Design Tokens: Named constants that define your design language
• Consumed by Atoms: Atoms import and use quarks for styling

Quarks vs Atoms

Aspect	Quarks	Atoms
Nature	Values/Tokens	UI Components
Render	Nothing (CSS variables, constants)	Visual elements
Examples	--color-primary-500, spacing.md	Button, Input, Label
Imports	None (base level)	Quarks only
Purpose	Define design language	Implement design language

Common Quark Types

Color Tokens

// quarks/colors.ts
export const colors = {
  // Brand colors
  primary: {
    50: '#e3f2fd',
    100: '#bbdefb',
    200: '#90caf9',
    300: '#64b5f6',
    400: '#42a5f5',
    500: '#2196f3', // Primary
    600: '#1e88e5',
    700: '#1976d2',
    800: '#1565c0',
    900: '#0d47a1',
  },

  // Semantic colors
  success: {
    light: '#4caf50',
    main: '#2e7d32',
    dark: '#1b5e20',
  },
  warning: {
    light: '#ff9800',
    main: '#ed6c02',
    dark: '#e65100',
  },
  danger: {
    light: '#ef5350',
    main: '#d32f2f',
    dark: '#c62828',
  },

  // Neutral colors
  neutral: {
    0: '#ffffff',
    50: '#fafafa',
    100: '#f5f5f5',
    200: '#eeeeee',
    300: '#e0e0e0',
    400: '#bdbdbd',
    500: '#9e9e9e',
    600: '#757575',
    700: '#616161',
    800: '#424242',
    900: '#212121',
  },
} as const;

export type ColorScale = keyof typeof colors;
export type PrimaryShade = keyof typeof colors.primary;

Spacing Tokens

// quarks/spacing.ts
export const spacing = {
  px: '1px',
  0: '0',
  0.5: '0.125rem', // 2px
  1: '0.25rem',    // 4px
  1.5: '0.375rem', // 6px
  2: '0.5rem',     // 8px
  2.5: '0.625rem', // 10px
  3: '0.75rem',    // 12px
  3.5: '0.875rem', // 14px
  4: '1rem',       // 16px
  5: '1.25rem',    // 20px
  6: '1.5rem',     // 24px
  7: '1.75rem',    // 28px
  8: '2rem',       // 32px
  9: '2.25rem',    // 36px
  10: '2.5rem',    // 40px
  12: '3rem',      // 48px
  14: '3.5rem',    // 56px
  16: '4rem',      // 64px
  20: '5rem',      // 80px
  24: '6rem',      // 96px
} as const;

// Semantic spacing aliases
export const spacingAliases = {
  none: spacing[0],
  xs: spacing[1],
  sm: spacing[2],
  md: spacing[4],
  lg: spacing[6],
  xl: spacing[8],
  '2xl': spacing[12],
  '3xl': spacing[16],
} as const;

Typography Tokens

// quarks/typography.ts
export const fontFamily = {
  sans: [
    'Inter',
    'ui-sans-serif',
    'system-ui',
    '-apple-system',
    'BlinkMacSystemFont',
    'Segoe UI',
    'Roboto',
    'sans-serif',
  ].join(', '),
  serif: [
    'Georgia',
    'Cambria',
    'Times New Roman',
    'Times',
    'serif',
  ].join(', '),
  mono: [
    'Fira Code',
    'ui-monospace',
    'SFMono-Regular',
    'Menlo',
    'Monaco',
    'Consolas',
    'monospace',
  ].join(', '),
} as const;

export const 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
  '6xl': '3.75rem', // 60px
} as const;

export const fontWeight = {
  thin: 100,
  extralight: 200,
  light: 300,
  normal: 400,
  medium: 500,
  semibold: 600,
  bold: 700,
  extrabold: 800,
  black: 900,
} as const;

export const lineHeight = {
  none: 1,
  tight: 1.25,
  snug: 1.375,
  normal: 1.5,
  relaxed: 1.625,
  loose: 2,
} as const;

export const letterSpacing = {
  tighter: '-0.05em',
  tight: '-0.025em',
  normal: '0em',
  wide: '0.025em',
  wider: '0.05em',
  widest: '0.1em',
} as const;

Border Tokens

// quarks/borders.ts
export const borderRadius = {
  none: '0',
  sm: '0.125rem',   // 2px
  DEFAULT: '0.25rem', // 4px
  md: '0.375rem',   // 6px
  lg: '0.5rem',     // 8px
  xl: '0.75rem',    // 12px
  '2xl': '1rem',    // 16px
  '3xl': '1.5rem',  // 24px
  full: '9999px',
} as const;

export const borderWidth = {
  DEFAULT: '1px',
  0: '0',
  2: '2px',
  4: '4px',
  8: '8px',
} as const;

Shadow Tokens

// quarks/shadows.ts
export const shadows = {
  none: 'none',
  sm: '0 1px 2px 0 rgb(0 0 0 / 0.05)',
  DEFAULT: '0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1)',
  md: '0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1)',
  lg: '0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1)',
  xl: '0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1)',
  '2xl': '0 25px 50px -12px rgb(0 0 0 / 0.25)',
  inner: 'inset 0 2px 4px 0 rgb(0 0 0 / 0.05)',
} as const;

// Focus ring shadows
export const focusRings = {
  primary: '0 0 0 3px rgba(33, 150, 243, 0.4)',
  danger: '0 0 0 3px rgba(239, 83, 80, 0.4)',
  success: '0 0 0 3px rgba(76, 175, 80, 0.4)',
} as const;

Animation Tokens

// quarks/animations.ts
export const duration = {
  instant: '0ms',
  fast: '100ms',
  normal: '200ms',
  slow: '300ms',
  slower: '500ms',
} as const;

export const easing = {
  linear: 'linear',
  in: 'cubic-bezier(0.4, 0, 1, 1)',
  out: 'cubic-bezier(0, 0, 0.2, 1)',
  inOut: 'cubic-bezier(0.4, 0, 0.2, 1)',
  bounce: 'cubic-bezier(0.68, -0.55, 0.265, 1.55)',
} as const;

export const transitions = {
  none: 'none',
  all: `all ${duration.normal} ${easing.inOut}`,
  colors: `background-color, border-color, color, fill, stroke ${duration.normal} ${easing.inOut}`,
  opacity: `opacity ${duration.normal} ${easing.inOut}`,
  shadow: `box-shadow ${duration.normal} ${easing.inOut}`,
  transform: `transform ${duration.normal} ${easing.inOut}`,
} as const;

Breakpoint Tokens

// quarks/breakpoints.ts
export const breakpoints = {
  xs: '320px',
  sm: '640px',
  md: '768px',
  lg: '1024px',
  xl: '1280px',
  '2xl': '1536px',
} as const;

// Media query helpers
export const mediaQueries = {
  xs: `@media (min-width: ${breakpoints.xs})`,
  sm: `@media (min-width: ${breakpoints.sm})`,
  md: `@media (min-width: ${breakpoints.md})`,
  lg: `@media (min-width: ${breakpoints.lg})`,
  xl: `@media (min-width: ${breakpoints.xl})`,
  '2xl': `@media (min-width: ${breakpoints['2xl']})`,
} as const;

Z-Index Tokens

// quarks/z-index.ts
export const zIndex = {
  hide: -1,
  base: 0,
  raised: 1,
  dropdown: 1000,
  sticky: 1100,
  fixed: 1200,
  overlay: 1300,
  modal: 1400,
  popover: 1500,
  tooltip: 1600,
  toast: 1700,
} as const;

CSS Custom Properties

Export quarks as CSS custom properties for runtime theming.

// quarks/css-variables.ts
import { colors, spacing, fontSize, fontFamily } from './index';

export function generateCSSVariables(): string {
  const lines: string[] = [':root {'];

  // Colors
  Object.entries(colors).forEach(([category, shades]) => {
    if (typeof shades === 'object') {
      Object.entries(shades).forEach(([shade, value]) => {
        lines.push(`  --color-${category}-${shade}: ${value};`);
      });
    }
  });

  // Spacing
  Object.entries(spacing).forEach(([key, value]) => {
    const sanitizedKey = key.replace('.', '_');
    lines.push(`  --spacing-${sanitizedKey}: ${value};`);
  });

  // Typography
  Object.entries(fontSize).forEach(([key, value]) => {
    lines.push(`  --font-size-${key}: ${value};`);
  });

  Object.entries(fontFamily).forEach(([key, value]) => {
    lines.push(`  --font-family-${key}: ${value};`);
  });

  lines.push('}');
  return lines.join('\n');
}

Generated CSS

/* quarks/variables.css - Generated output */
:root {
  /* Colors - Primary */
  --color-primary-50: #e3f2fd;
  --color-primary-100: #bbdefb;
  --color-primary-500: #2196f3;
  --color-primary-900: #0d47a1;

  /* Colors - Neutral */
  --color-neutral-0: #ffffff;
  --color-neutral-100: #f5f5f5;
  --color-neutral-900: #212121;

  /* Spacing */
  --spacing-0: 0;
  --spacing-1: 0.25rem;
  --spacing-2: 0.5rem;
  --spacing-4: 1rem;
  --spacing-8: 2rem;

  /* Typography */
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;

  --font-family-sans: Inter, ui-sans-serif, system-ui, sans-serif;
  --font-family-mono: Fira Code, ui-monospace, monospace;

  /* Borders */
  --border-radius-sm: 0.125rem;
  --border-radius-md: 0.375rem;
  --border-radius-lg: 0.5rem;
  --border-radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);

  /* Transitions */
  --duration-fast: 100ms;
  --duration-normal: 200ms;
  --duration-slow: 300ms;
  --easing-in-out: cubic-bezier(0.4, 0, 0.2, 1);
}

Directory Structure

Recommended Structure

src/
  quarks/                    # Design tokens
    index.ts                 # Barrel export
    colors.ts
    spacing.ts
    typography.ts
    borders.ts
    shadows.ts
    animations.ts
    breakpoints.ts
    z-index.ts
    css-variables.ts         # CSS custom property generator
    variables.css            # Generated CSS file
  components/
    atoms/                   # Atoms that consume quarks
      Button/
      Input/
    molecules/
    organisms/
    templates/
    pages/

Index Barrel Export

// quarks/index.ts
export * from './colors';
export * from './spacing';
export * from './typography';
export * from './borders';
export * from './shadows';
export * from './animations';
export * from './breakpoints';
export * from './z-index';

Using Quarks in Atoms

CSS-in-JS (styled-components/emotion)

// atoms/Button/Button.tsx
import styled from 'styled-components';
import { colors, spacing, fontSize, borderRadius, transitions } from '@/quarks';

export const Button = styled.button<{ variant?: 'primary' | 'secondary' }>`
  padding: ${spacing[2]} ${spacing[4]};
  font-size: ${fontSize.base};
  border-radius: ${borderRadius.md};
  transition: ${transitions.colors};

  ${({ variant = 'primary' }) =>
    variant === 'primary'
      ? `
        background-color: ${colors.primary[500]};
        color: ${colors.neutral[0]};

        &:hover {
          background-color: ${colors.primary[600]};
        }
      `
      : `
        background-color: transparent;
        color: ${colors.primary[500]};
        border: 1px solid ${colors.primary[500]};

        &:hover {
          background-color: ${colors.primary[50]};
        }
      `}
`;

CSS Modules with Variables

// atoms/Button/Button.tsx
import styles from './Button.module.css';

export const Button = ({ variant = 'primary', children }) => (
  <button className={`${styles.button} ${styles[variant]}`}>
    {children}
  </button>
);

/* atoms/Button/Button.module.css */
.button {
  padding: var(--spacing-2) var(--spacing-4);
  font-size: var(--font-size-base);
  border-radius: var(--border-radius-md);
  transition: var(--duration-normal) var(--easing-in-out);
}

.primary {
  background-color: var(--color-primary-500);
  color: var(--color-neutral-0);
}

.primary:hover {
  background-color: var(--color-primary-600);
}

.secondary {
  background-color: transparent;
  color: var(--color-primary-500);
  border: 1px solid var(--color-primary-500);
}

Tailwind CSS Integration

// tailwind.config.js
const { colors, spacing, fontSize, borderRadius } = require('./src/quarks');

module.exports = {
  theme: {
    colors,
    spacing,
    fontSize,
    borderRadius,
  },
};

Theming with Quarks

Dark Mode Support

// quarks/themes.ts
import { colors } from './colors';

export const lightTheme = {
  background: colors.neutral[0],
  foreground: colors.neutral[900],
  muted: colors.neutral[100],
  mutedForeground: colors.neutral[500],
  primary: colors.primary[500],
  primaryForeground: colors.neutral[0],
};

export const darkTheme = {
  background: colors.neutral[900],
  foreground: colors.neutral[0],
  muted: colors.neutral[800],
  mutedForeground: colors.neutral[400],
  primary: colors.primary[400],
  primaryForeground: colors.neutral[900],
};

export type Theme = typeof lightTheme;

CSS Variables for Theming

/* quarks/theme-light.css */
:root {
  --background: var(--color-neutral-0);
  --foreground: var(--color-neutral-900);
  --muted: var(--color-neutral-100);
  --primary: var(--color-primary-500);
}

/* quarks/theme-dark.css */
[data-theme="dark"] {
  --background: var(--color-neutral-900);
  --foreground: var(--color-neutral-0);
  --muted: var(--color-neutral-800);
  --primary: var(--color-primary-400);
}

Best Practices

1. Use Semantic Names

// GOOD: Semantic naming
export const colors = {
  primary: { ... },
  danger: { ... },
  success: { ... },
};

// BAD: Raw color names
export const colors = {
  blue: { ... },
  red: { ... },
  green: { ... },
};

2. Consistent Scales

// GOOD: Consistent scale pattern
export const colors = {
  primary: { 50, 100, 200, 300, 400, 500, 600, 700, 800, 900 },
  secondary: { 50, 100, 200, 300, 400, 500, 600, 700, 800, 900 },
};

// BAD: Inconsistent scales
export const colors = {
  primary: { light, medium, dark },
  secondary: { 100, 500, 900 },
};

3. Type Safety

// GOOD: Type-safe tokens
export const spacing = { ... } as const;
export type SpacingKey = keyof typeof spacing;

function getSpacing(key: SpacingKey): string {
  return spacing[key];
}

// BAD: Untyped strings
function getSpacing(key: string): string {
  return spacing[key]; // No type checking
}

4. Single Source of Truth

// GOOD: Quarks as the only source
// All components import from quarks
import { colors } from '@/quarks';

// BAD: Duplicate values
const Button = styled.button`
  color: #2196f3; // Hardcoded, not from quarks!
`;

5. Documentation

// GOOD: Document your tokens
/**
 * Primary color scale
 * Use 500 for default primary actions
 * Use 600+ for hover/active states
 * Use 100-400 for backgrounds/accents
 */
export const primary = { ... };

Anti-Patterns to Avoid

1. Quarks with Logic

// BAD: Quarks should be pure values
export const getColor = (isDark: boolean) =>
  isDark ? '#ffffff' : '#000000';

// GOOD: Pure values, logic in components/themes
export const colors = {
  light: { text: '#000000' },
  dark: { text: '#ffffff' },
};

2. Component-Specific Tokens

// BAD: Token for specific component
export const buttonPrimaryBackground = '#2196f3';

// GOOD: Generic semantic tokens
export const colors = {
  primary: { 500: '#2196f3' },
};

3. Too Many Tokens

// BAD: Token for every possible value
export const spacing = {
  1: '1px',
  2: '2px',
  3: '3px',
  4: '4px',
  5: '5px',
  // ... 100 more values
};

// GOOD: Deliberate, usable scale
export const spacing = {
  1: '0.25rem',
  2: '0.5rem',
  4: '1rem',
  6: '1.5rem',
  8: '2rem',
};

When to Use This Skill

• Setting up design tokens for a new design system
• Organizing existing CSS variables into a structured system
• Creating theme-able component libraries
• Ensuring consistency across a large codebase
• Building white-label or multi-brand applications
• Migrating from hardcoded values to design tokens

Related Skills

• atomic-design-fundamentals - Core methodology overview
• atomic-design-atoms - Creating atomic components that consume quarks
• atomic-design-integration - Framework-specific implementation patterns

Resources

Documentation

• Design Tokens W3C Community Group: https://www.w3.org/community/design-tokens/
• Style Dictionary: https://amzn.github.io/style-dictionary/
• Tokens Studio: https://tokens.studio/

Tools

• Figma Tokens: https://www.figma.com/community/plugin/843461159747178978
• Style Dictionary: https://amzn.github.io/style-dictionary/
• Theme UI: https://theme-ui.com/