CSS Grid: A Complete Guide to Modern Layouts | Alex Mercer

Design systems are the backbone of consistent user interfaces. Here’s how to build one that scales.

Why Design Systems Matter

A well-crafted design system provides:

Consistency across all products
Faster development with reusable components
Better collaboration between designers and developers
Reduced technical debt over time

Core Principles

1. Start with Tokens

Design tokens are the atomic values of your system:

tokens.ts

export const tokens = {
  colors: {
    primary: {
      50: '#eff6ff',
      500: '#3b82f6',
      900: '#1e3a8a',
    },
    neutral: {
      0: '#ffffff',
      100: '#f5f5f5',
      900: '#171717',
    },
  },
  spacing: {
    xs: '0.25rem',
    sm: '0.5rem',
    md: '1rem',
    lg: '1.5rem',
    xl: '2rem',
  },
  radii: {
    sm: '0.25rem',
    md: '0.5rem',
    lg: '1rem',
    full: '9999px',
  },
} as const;

2. Build Primitive Components

Start with the basics:

Button.tsx

import { cva, type VariantProps } from "class-variance-authority";
 
const buttonVariants = cva(
  "inline-flex items-center justify-center rounded-md font-medium transition-colors",
  {
    variants: {
      variant: {
        primary: "bg-primary text-white hover:bg-primary/90",
        secondary: "bg-secondary text-secondary-foreground hover:bg-secondary/80",
        ghost: "hover:bg-accent hover:text-accent-foreground",
      },
      size: {
        sm: "h-8 px-3 text-sm",
        md: "h-10 px-4",
        lg: "h-12 px-6 text-lg",
      },
    },
    defaultVariants: {
      variant: "primary",
      size: "md",
    },
  }
);
 
interface ButtonProps
  extends React.ButtonHTMLAttributes<HTMLButtonElement>,
    VariantProps<typeof buttonVariants> {}
 
export function Button({ variant, size, className, ...props }: ButtonProps) {
  return (
    <button className={buttonVariants({ variant, size, className })} {...props} />
  );
}

Component Composition

Build complex components from primitives:

Level	Examples	Purpose
Tokens	Colors, spacing, typography	Foundation
Primitives	Button, Input, Badge	Building blocks
Patterns	Card, Modal, Dropdown	Common UI patterns
Templates	PageHeader, Sidebar	Layout structures

Documentation is Key

“A design system without documentation is just a component library.”

Every component should include:

Usage examples - Show common use cases
Props documentation - Explain all options
Accessibility notes - ARIA labels, keyboard nav
Do’s and Don’ts - Guide proper usage

Versioning Strategy

package.json

{
  "name": "@company/design-system",
  "version": "2.1.0",
  "peerDependencies": {
    "react": "^18.0.0",
    "tailwindcss": "^3.0.0"
  }
}

Use semantic versioning:

Major: Breaking changes
Minor: New features (backward compatible)
Patch: Bug fixes

Conclusion

Building a design system is an investment that pays dividends in:

Developer productivity
Design consistency
User experience
Team collaboration

Start small, iterate often, and document everything.