Setup

Create app/globals.css

@import "tailwindcss";

Equivalent to

@layer theme, base, components, utilities;
@import "tailwindcss/theme.css" layer(theme);
@import "tailwindcss/preflight.css" layer(base);
@import "tailwindcss/utilities.css" layer(utilities);

In app/layout.tsx

import './globals.css';

Layer Order

Tailwind v4 layers (top → bottom):

• @theme: CSS custom tokens (--color-primary)
• @base: raw element styles (html, body, h1)
• @components: reusable, named class styles (optionally using @apply)
• @utilities: atomic utility classes (text-sm, bg-red-500)

@theme {
  --font-display: "Satoshi", "sans-serif";

  --breakpoint-3xl: 120rem;

  --color-avocado-100: oklch(0.99 0 0);
  --color-avocado-200: oklch(0.98 0.04 113.22);
  --color-avocado-300: oklch(0.94 0.11 115.03);
  --color-avocado-400: oklch(0.92 0.19 114.08);
  --color-avocado-500: oklch(0.84 0.18 117.33);
  --color-avocado-600: oklch(0.53 0.12 118.34);

  --ease-fluid: cubic-bezier(0.3, 0, 0, 1);
  --ease-snappy: cubic-bezier(0.2, 0, 0, 1);
}

@layer base {
  h1 {
    font-size: var(--text-2xl);
  }
  h2 {
    font-size: var(--text-xl);
  }
}

@layer components {
  .card {
    background-color: var(--color-white);
    border-radius: var(--rounded-lg);
    padding: var(--spacing-6);
    box-shadow: var(--shadow-xl);
  }
}

@utility tab-4 {
  tab-size: 4;
}