Apply Design System

Use design tokens exclusively. Never use arbitrary values ([#hex], [16px], etc.).

Color Tokens

Backgrounds

bg-background, bg-card, bg-popover, bg-primary, bg-secondary, bg-muted, bg-accent, bg-destructive

Text

text-foreground, text-muted-foreground, text-primary-foreground, text-secondary-foreground, text-accent-foreground, text-destructive-foreground

Borders

border (default), border-input, border-ring

Spacing (Padding/Margin/Gap)

0, 1, 2, 4, 6, 8, 12, 16, 20, 24 — e.g., p-4, gap-6, space-y-4

Typography

• Sizes: text-xs, text-sm, text-base, text-lg, text-xl, text-2xl, text-3xl, text-4xl
• Weights: font-normal, font-medium, font-semibold, font-bold
• Families: font-sans, font-heading, font-mono

Borders & Radius

rounded-sm, rounded, rounded-md, rounded-lg, rounded-xl, rounded-full

Shadows

shadow-sm, shadow, shadow-md, shadow-lg, shadow-xl

Common Patterns

Card: bg-card text-card-foreground rounded-lg border shadow-sm p-6

Primary button: bg-primary text-primary-foreground hover:bg-primary/90 px-4 py-2 rounded-md font-medium

Input: flex h-10 w-full rounded-md border border-input bg-background px-3 py-2 text-sm

Container: container mx-auto px-4 py-8

Using cn() for class merging

import { cn } from '@acme/design-system/utils/style'

<div className={cn('base-styles', { 'conditional': variant === 'x' }, className)}>

Responsive (mobile-first)

md: (768px+), lg: (1024px+), xl: (1280px+)

Anti-Patterns

• bg-[#FF0000] — use semantic tokens
• bg-red-500 — use semantic tokens
• p-[16px] — use p-4
• style={{ ... }} — use Tailwind classes
• w-[250px] — use w-64 or similar

When Tokens Don't Exist

1. Check for a close semantic token
2. Add to design tokens package (packages/design-tokens/)
3. Update Tailwind config
4. Document in docs/typography-and-color.md