Building Scalable Design Systems with Tailwind v4

Tailwind CSS v4 introduces a completely new approach to styling with its CSS-first configuration model. In this guide, we'll walk through how we built a scalable design system at Agency using the latest features.

CSS-First Configuration

The most significant change in Tailwind v4 is the shift from JavaScript configuration to native CSS. The new @theme directive allows you to define design tokens directly in your CSS, making it more intuitive and powerful.

Building Component Primitives

We start with atomic tokens—colors, typography, spacing—and compose them into component primitives using the new @layer and @variant directives. This creates a clear hierarchy that scales.

Performance Optimizations

Tailwind v4's new engine is built on Lightning CSS, offering dramatically faster build times. Combined with proper purging and lazy loading, your production CSS can be under 10KB.