Design System Architecture

Design System Architecture

Create consistent, scalable visual languages that evolve gracefully

This skill provides frameworks for building design systems that scale from single projects to entire organizations.

Core Principles

1. Tokens Are Truth

Design decisions should be encoded as tokens (variables). Nothing should be hard-coded.

2. Constraints Enable Creativity

A good design system provides guardrails that speed up decisions, not slow them down.

3. Components Over Compositions

Build primitives that compose into anything, not specific layouts that restrict.

Token Architecture

The Token Hierarchy

┌─────────────────────────────────────────────────────────────┐
│                     SEMANTIC TOKENS                          │
│  (What they mean: --color-primary, --spacing-section)       │
└────────────────────────────┬────────────────────────────────┘
                             │ Reference
                             ▼
┌─────────────────────────────────────────────────────────────┐
│                     ALIAS TOKENS                             │
│  (Design decisions: --color-brand-primary, --size-lg)       │
└────────────────────────────┬────────────────────────────────┘
                             │ Reference
                             ▼
┌─────────────────────────────────────────────────────────────┐
│                     PRIMITIVE TOKENS                         │
│  (Raw values: --blue-500, --space-16, --font-inter)         │
└─────────────────────────────────────────────────────────────┘

Primitive Tokens

Raw values with no semantic meaning.

/* Colors - use naming that indicates value, not usage */
--gray-50: #fafafa;
--gray-100: #f5f5f5;
--gray-200: #e5e5e5;
--gray-300: #d4d4d4;
--gray-400: #a3a3a3;
--gray-500: #737373;
--gray-600: #525252;
--gray-700: #404040;
--gray-800: #262626;
--gray-900: #171717;

--blue-50: #eff6ff;
--blue-100: #dbeafe;
--blue-200: #bfdbfe;
--blue-300: #93c5fd;
--blue-400: #60a5fa;
--blue-500: #3b82f6;
--blue-600: #2563eb;
--blue-700: #1d4ed8;
--blue-800: #1e40af;
--blue-900: #1e3a8a;

/* Spacing - use consistent scale */
--space-0: 0;
--space-1: 0.25rem;   /* 4px */
--space-2: 0.5rem;    /* 8px */
--space-3: 0.75rem;   /* 12px */
--space-4: 1rem;      /* 16px */
--space-5: 1.25rem;   /* 20px */
--space-6: 1.5rem;    /* 24px */
--space-8: 2rem;      /* 32px */
--space-10: 2.5rem;   /* 40px */
--space-12: 3rem;     /* 48px */
--space-16: 4rem;     /* 64px */
--space-20: 5rem;     /* 80px */
--space-24: 6rem;     /* 96px */

/* Typography */
--font-sans: system-ui, -apple-system, sans-serif;
--font-mono: ui-monospace, monospace;

--text-xs: 0.75rem;    /* 12px */
--text-sm: 0.875rem;   /* 14px */
--text-base: 1rem;     /* 16px */
--text-lg: 1.125rem;   /* 18px */
--text-xl: 1.25rem;    /* 20px */
--text-2xl: 1.5rem;    /* 24px */
--text-3xl: 1.875rem;  /* 30px */
--text-4xl: 2.25rem;   /* 36px */
--text-5xl: 3rem;      /* 48px */

--leading-tight: 1.25;
--leading-normal: 1.5;
--leading-relaxed: 1.75;

--weight-normal: 400;
--weight-medium: 500;
--weight-semibold: 600;
--weight-bold: 700;

Alias Tokens

Design decisions that reference primitives.

/* Brand colors */
--color-brand-primary: var(--blue-600);
--color-brand-primary-hover: var(--blue-700);
--color-brand-secondary: var(--gray-600);

/* Size scale */
--size-xs: var(--space-2);
--size-sm: var(--space-3);
--size-md: var(--space-4);
--size-lg: var(--space-6);
--size-xl: var(--space-8);

/* Radius */
--radius-none: 0;
--radius-sm: 0.125rem;
--radius-md: 0.375rem;
--radius-lg: 0.5rem;
--radius-xl: 0.75rem;
--radius-full: 9999px;

Semantic Tokens

Tokens that describe usage, not values.

/* Backgrounds */
--color-bg-primary: var(--white);
--color-bg-secondary: var(--gray-50);
--color-bg-tertiary: var(--gray-100);
--color-bg-inverse: var(--gray-900);

/* Text */
--color-text-primary: var(--gray-900);
--color-text-secondary: var(--gray-600);
--color-text-tertiary: var(--gray-400);
--color-text-inverse: var(--white);
--color-text-link: var(--color-brand-primary);

/* Borders */
--color-border-default: var(--gray-200);
--color-border-strong: var(--gray-300);
--color-border-focus: var(--color-brand-primary);

/* States */
--color-success: var(--green-600);
--color-warning: var(--yellow-500);
--color-error: var(--red-600);
--color-info: var(--blue-600);

/* Component tokens */
--button-padding-x: var(--space-4);
--button-padding-y: var(--space-2);
--button-radius: var(--radius-md);
--button-font-weight: var(--weight-medium);

--input-padding: var(--space-3);
--input-border-width: 1px;
--input-radius: var(--radius-md);

--card-padding: var(--space-6);
--card-radius: var(--radius-lg);
--card-shadow: 0 1px 3px rgba(0,0,0,0.1);

Color System

Building a Color Palette

Color Palette Structure:

  Neutrals:
    Purpose: Text, backgrounds, borders
    Scale: 50-900 (10 shades minimum)
    Key values:
      - 50: Subtle backgrounds
      - 100-200: Secondary backgrounds
      - 400-500: Placeholder text
      - 600-700: Secondary text
      - 800-900: Primary text

  Brand Primary:
    Purpose: CTAs, links, key actions
    Scale: 50-900
    Key values:
      - 500-600: Main brand color
      - 600-700: Hover states
      - 100-200: Light backgrounds

  Brand Secondary:
    Purpose: Accents, secondary actions
    Scale: 50-900 (can be smaller)

  Semantic Colors:
    Success: Typically green family
    Warning: Typically yellow/amber family
    Error: Typically red family
    Info: Typically blue family

Dark Mode Strategy

/* Light theme (default) */
:root {
  --color-bg-primary: var(--white);
  --color-bg-secondary: var(--gray-50);
  --color-text-primary: var(--gray-900);
  --color-text-secondary: var(--gray-600);
  --color-border-default: var(--gray-200);
}

/* Dark theme */
[data-theme="dark"] {
  --color-bg-primary: var(--gray-900);
  --color-bg-secondary: var(--gray-800);
  --color-text-primary: var(--gray-50);
  --color-text-secondary: var(--gray-400);
  --color-border-default: var(--gray-700);
}

/* System preference */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-bg-primary: var(--gray-900);
    /* ... dark values ... */
  }
}

Typography System

Type Scale

Typography Scale:

  Display:
    - display-2xl: 4.5rem/1.1 (72px) - Hero headlines
    - display-xl: 3.75rem/1.1 (60px) - Major headings
    - display-lg: 3rem/1.1 (48px) - Section headlines

  Headings:
    - heading-xl: 2.25rem/1.25 (36px) - Page titles
    - heading-lg: 1.875rem/1.3 (30px) - Section titles
    - heading-md: 1.5rem/1.35 (24px) - Subsections
    - heading-sm: 1.25rem/1.4 (20px) - Card titles
    - heading-xs: 1.125rem/1.4 (18px) - Small headings

  Body:
    - body-lg: 1.125rem/1.6 (18px) - Lead paragraphs
    - body-md: 1rem/1.6 (16px) - Default body
    - body-sm: 0.875rem/1.5 (14px) - Secondary text

  Utility:
    - caption: 0.75rem/1.4 (12px) - Labels, captions
    - overline: 0.75rem/1.4 uppercase tracked - Categories

Implementing Type Scale

/* Type scale implementation */
.text-display-2xl {
  font-size: var(--text-5xl);
  line-height: 1.1;
  font-weight: var(--weight-bold);
  letter-spacing: -0.02em;
}

.text-heading-xl {
  font-size: var(--text-4xl);
  line-height: 1.25;
  font-weight: var(--weight-semibold);
  letter-spacing: -0.01em;
}

.text-body-md {
  font-size: var(--text-base);
  line-height: 1.6;
  font-weight: var(--weight-normal);
}

Spacing System

Spacing Scale Philosophy

Spacing Philosophy:

  Base Unit: 4px (0.25rem)

  Scale Type: Geometric with adjustments

  Common uses:
    - 4px (space-1): Icon gaps, tight spacing
    - 8px (space-2): Inline elements, button padding (y)
    - 12px (space-3): Form inputs padding
    - 16px (space-4): Component padding, button padding (x)
    - 24px (space-6): Card padding, section gaps
    - 32px (space-8): Related section spacing
    - 48px (space-12): Unrelated section spacing
    - 64px (space-16): Major page sections
    - 96px (space-24): Hero/footer spacing

Spacing Usage Guidelines

Component Spacing:

  Buttons:
    Padding: space-2 space-4 (8px 16px)
    Gap between: space-2 (8px)

  Cards:
    Padding: space-6 (24px)
    Gap between: space-6 (24px)
    Internal gaps: space-4 (16px)

  Forms:
    Input padding: space-3 (12px)
    Label to input: space-2 (8px)
    Between fields: space-6 (24px)

  Lists:
    Item padding: space-3 space-4
    Between items: space-1 or space-2

Page Spacing:

  Section padding: space-16 to space-24 (64-96px)
  Content width: max 80ch for prose
  Grid gaps: space-6 to space-8

Component Architecture

Component Anatomy

Component Anatomy:

  Button Example:

    Container:
      - Background color (semantic)
      - Border radius (from scale)
      - Border (optional)
      - Padding (from scale)
      - Min height/width

    Content:
      - Text color (semantic)
      - Font size (from scale)
      - Font weight (from scale)
      - Line height
      - Letter spacing

    Icon (optional):
      - Size (proportional)
      - Color (inherit or specific)
      - Spacing from text

    States:
      - Default
      - Hover
      - Active/Pressed
      - Focus (keyboard)
      - Disabled
      - Loading

Component Variants Pattern

/* Base component */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--button-padding-y) var(--button-padding-x);
  border-radius: var(--button-radius);
  font-weight: var(--button-font-weight);
  transition: all 150ms ease;
}

/* Variants */
.btn-primary {
  background: var(--color-brand-primary);
  color: var(--color-text-inverse);
}

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

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

.btn-ghost {
  background: transparent;
  color: var(--color-text-primary);
}

/* Sizes */
.btn-sm {
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-sm);
}

.btn-lg {
  padding: var(--space-3) var(--space-6);
  font-size: var(--text-lg);
}

Tailwind Integration

Custom Tailwind Config

// tailwind.config.js
module.exports = {
  theme: {
    colors: {
      // Map to your tokens
      transparent: 'transparent',
      current: 'currentColor',

      // Primitives
      gray: {
        50: 'var(--gray-50)',
        100: 'var(--gray-100)',
        // ... etc
      },

      // Semantic (recommended approach)
      bg: {
        primary: 'var(--color-bg-primary)',
        secondary: 'var(--color-bg-secondary)',
        tertiary: 'var(--color-bg-tertiary)',
      },
      text: {
        primary: 'var(--color-text-primary)',
        secondary: 'var(--color-text-secondary)',
      },
      border: {
        DEFAULT: 'var(--color-border-default)',
        strong: 'var(--color-border-strong)',
      },
    },

    spacing: {
      0: 'var(--space-0)',
      1: 'var(--space-1)',
      2: 'var(--space-2)',
      // ... etc
    },

    borderRadius: {
      none: 'var(--radius-none)',
      sm: 'var(--radius-sm)',
      DEFAULT: 'var(--radius-md)',
      lg: 'var(--radius-lg)',
      full: 'var(--radius-full)',
    },

    fontSize: {
      xs: ['var(--text-xs)', { lineHeight: '1.4' }],
      sm: ['var(--text-sm)', { lineHeight: '1.5' }],
      base: ['var(--text-base)', { lineHeight: '1.6' }],
      // ... etc
    },
  },
}

Animation System

Animation Tokens

/* Duration */
--duration-instant: 0ms;
--duration-fast: 100ms;
--duration-normal: 200ms;
--duration-slow: 300ms;
--duration-slower: 500ms;

/* Easing */
--ease-linear: linear;
--ease-in: cubic-bezier(0.4, 0, 1, 1);
--ease-out: cubic-bezier(0, 0, 0.2, 1);
--ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);
--ease-bounce: cubic-bezier(0.68, -0.55, 0.265, 1.55);

Common Animation Patterns

/* Fade in */
@keyframes fade-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* Slide up */
@keyframes slide-up {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Scale in */
@keyframes scale-in {
  from {
    opacity: 0;
    transform: scale(0.95);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

/* Usage */
.animate-fade-in {
  animation: fade-in var(--duration-normal) var(--ease-out);
}

.animate-slide-up {
  animation: slide-up var(--duration-normal) var(--ease-out);
}

Quality Checklist

Design System Audit

• All colors use tokens (no hex values in components)
• All spacing uses scale values
• Typography uses defined scale
• Components have all states defined
• Dark mode tested
• Accessibility contrast ratios met (4.5:1 body, 3:1 large)
• Focus states visible
• Motion respects prefers-reduced-motion
• Tokens documented
• Component API documented

"A design system is not a project. It's a product, serving products."