Tailwind CSS Academy · Lección

Crear la capa de tokens y configuración

Implemente sus tokens de diseño como variables CSS, conéctelos a la configuración de Tailwind y pruébelos en los modos claro y oscuro.

Crear la capa de tokens y configuración es una lección gratuita de Tailwind CSS Academy en CoddyKit. Esta es la lección 2 de 4. Puedes leer la lección completa abajo gratuitamente — luego la practicas en el navegador con un editor de código integrado y un tutor de IA 24/7. Forma parte de la ruta de aprendizaje de Tailwind CSS Academy, y tu progreso se sincroniza en la web y la app de CoddyKit. El curso de Tailwind CSS Academy incluye 4 lecciones en total.

Partes de esta lección aún no han sido traducidas y se muestran en inglés.

Token Layer Overview

The token layer is the bridge between your design decisions and Tailwind's utility generation. It consists of CSS custom properties (design tokens at the CSS level) and the Tailwind config that references those properties. When implemented correctly, swapping a theme requires only changing the CSS variable values — no Tailwind class names change, no component code changes.

Defining Primitive Tokens

Start by defining all raw color, spacing, and typography values in a tokens/primitives.css file using CSS custom properties. These primitives are not used directly by components — they exist only to feed the semantic token layer. Use a structured naming convention like --color-blue-500 for colors and --space-4 for spacing values.

/* tokens/primitives.css */
:root {
  /* Color primitives */
  --color-blue-50: #eff6ff;
  --color-blue-100: #dbeafe;
  --color-blue-500: #3b82f6;
  --color-blue-600: #2563eb;
  --color-blue-700: #1d4ed8;
  --color-blue-900: #1e3a8a;

  --color-gray-50: #f9fafb;
  --color-gray-100: #f3f4f6;
  --color-gray-500: #6b7280;
  --color-gray-900: #111827;

  --color-white: #ffffff;
  --color-black: #000000;

  /* Spacing primitives */
  --space-1: 0.25rem;
  --space-4: 1rem;
  --space-8: 2rem;
}

Defining Semantic Tokens

Semantic tokens give meaning to primitive values. Define them in a separate tokens/semantic.css file. Each semantic token references a primitive token and represents a purpose rather than a value. The same semantic token is overridden in a dark mode scope or a different brand scope to achieve theme switching.

/* tokens/semantic.css */
:root {
  /* Brand colors */
  --color-primary:       var(--color-blue-600);
  --color-primary-hover: var(--color-blue-700);
  --color-primary-light: var(--color-blue-50);

  /* Surface colors */
  --color-surface:         var(--color-white);
  --color-surface-elevated: var(--color-gray-50);

  /* Text colors */
  --color-text-primary:   var(--color-gray-900);
  --color-text-secondary: var(--color-gray-500);

  /* Border colors */
  --color-border: var(--color-gray-100);
}

Dark Mode Token Override

Override semantic tokens under the .dark class (for class strategy) or @media (prefers-color-scheme: dark) (for media strategy). Only semantic tokens change — primitive definitions remain unchanged. This is the power of the two-tier system: dark mode is implemented entirely in the token layer, with zero changes to component CSS or Tailwind classes.

/* tokens/semantic.css (dark mode overrides) */
:root {
  --color-surface: #ffffff;
  --color-text-primary: #111827;
  --color-border: #f3f4f6;
}

.dark {
  --color-surface: #111827;        /* was white */
  --color-text-primary: #f9fafb;   /* was dark gray */
  --color-border: #1f2937;         /* was light gray */
  --color-surface-elevated: #1f2937;
  /* --color-primary unchanged: blue works in both modes */
}

Wiring Tokens Into Tailwind Config

Reference CSS custom properties inside the Tailwind config's theme extension. Use var(--token-name) as the value. This means every Tailwind utility that references the theme token will use the CSS variable at runtime, enabling live theme switching without recompilation. The JIT engine generates classes with var() values in the output CSS.

// tailwind.config.js
module.exports = {
  theme: {
    extend: {
      colors: {
        primary: {
          DEFAULT: 'var(--color-primary)',
          hover: 'var(--color-primary-hover)',
          light: 'var(--color-primary-light)',
        },
        surface: 'var(--color-surface)',
        'text-primary': 'var(--color-text-primary)',
        'text-secondary': 'var(--color-text-secondary)',
        border: 'var(--color-border)',
      },
    },
  },
};

Using Token-Based Utilities in Components

With tokens wired into the config, you use them like any other Tailwind color. bg-surface applies the --color-surface CSS variable as a background. When the user switches to dark mode, the CSS variable value changes, and the background updates automatically without any component changes. Token-based classes look identical to built-in Tailwind classes in the markup.

<!-- Token-based Tailwind classes look just like built-in ones -->
<div class="bg-surface border border-border rounded-xl p-6">
  <h2 class="text-text-primary font-semibold">Card Title</h2>
  <p class="mt-2 text-text-secondary text-sm">Card description</p>
  <button class="mt-4 rounded-lg bg-primary px-4 py-2 font-semibold text-white
                 hover:bg-primary-hover transition">
    Primary Action
  </button>
</div>

Typography Tokens

Define font family, font size, line height, and font weight as tokens. Font families should reference a CSS variable so switching brand typefaces requires only a variable change. Font sizes can be extended in the Tailwind config with semantic names like text-display and text-caption alongside the default numeric scale.

/* tokens/semantic.css */
:root {
  --font-sans: 'Inter', ui-sans-serif, system-ui, sans-serif;
  --font-display: 'Cal Sans', var(--font-sans);
  --font-mono: 'JetBrains Mono', ui-monospace, monospace;
}

// tailwind.config.js
theme: {
  extend: {
    fontFamily: {
      sans: ['var(--font-sans)'],
      display: ['var(--font-display)'],
      mono: ['var(--font-mono)'],
    },
    fontSize: {
      display: ['3.75rem', { lineHeight: '1.1', fontWeight: '700' }],
      caption: ['0.75rem', { lineHeight: '1.5' }],
    },
  },
},

Spacing and Radius Tokens

Extend the spacing and border radius scales with semantic names for component-level constants. Rather than remembering that cards use rounded-xl and badges use rounded-full, define radius.card: xl and radius.badge: full in the config. This makes component code self-documenting and ensures all cards use the same radius even when the value changes.

// tailwind.config.js
theme: {
  extend: {
    borderRadius: {
      card:  '0.75rem',   // 12px — used by Card, Dialog
      input: '0.5rem',    // 8px  — used by Input, Select
      badge: '9999px',    // pill — used by Badge, Tag
      button: '0.5rem',   // 8px  — used by all Button variants
    },
    spacing: {
      18: '4.5rem',
      22: '5.5rem',
      128: '32rem',
    },
  },
},

Shadow Tokens

Define consistent shadow levels in the Tailwind config using semantic names. Shadows communicate visual hierarchy: none for flat elements, card for surface elements, elevated for dropdowns and modals, focus for interactive state indicators. This prevents arbitrary shadow values scattered across the codebase.

// tailwind.config.js
theme: {
  extend: {
    boxShadow: {
      card:     '0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1)',
      elevated: '0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1)',
      focus:    '0 0 0 3px var(--color-primary-light)',
    },
  },
},

<!-- Use semantic shadow names -->
<div class="shadow-card hover:shadow-elevated transition-shadow">

Validating Tokens in CI

Add a CI step that validates token integrity — checking that every semantic token references a primitive that exists, and that no semantic token is a raw hex value (which would bypass the two-tier system). A simple Node.js script that parses the CSS variable file and checks references can catch token drift before it reaches production.

// scripts/validate-tokens.js
const fs = require('fs');
const semanticCss = fs.readFileSync('tokens/semantic.css', 'utf8');
const primitiveCss = fs.readFileSync('tokens/primitives.css', 'utf8');

// Extract all var() references in semantic.css
const refs = [...semanticCss.matchAll(/var\(([^)]+)\)/g)].map(m => m[1].trim());

// Check each ref exists in primitives.css
const missing = refs.filter(ref => !primitiveCss.includes(ref + ':'));
if (missing.length > 0) {
  console.error('Undefined primitive tokens:', missing);
  process.exit(1);
}
console.log('All tokens valid.');

Testing Dark Mode Token Switching

Test dark mode visually at the token level by toggling the .dark class on html and verifying that every semantic color surface, text, and border renders correctly. Use Playwright or Cypress to take screenshots with dark applied and compare against light mode baselines. Run this test suite whenever the token file changes to catch visual regressions immediately.

// playwright/dark-mode.spec.ts
import { test, expect } from '@playwright/test';

test('tokens switch correctly in dark mode', async ({ page }) => {
  await page.goto('/tokens-preview');

  // Light mode screenshot
  await expect(page).toHaveScreenshot('tokens-light.png');

  // Enable dark mode
  await page.evaluate(() =>
    document.documentElement.classList.add('dark')
  );

  // Dark mode screenshot
  await expect(page).toHaveScreenshot('tokens-dark.png');
});

Quick Check

Test your understanding of Tailwind CSS Mastery concepts from this lesson.

Lesson Recap

In this lesson you learned: defining primitive and semantic tokens as CSS custom properties in separate files, wiring semantic tokens into the Tailwind config using var() so they update at runtime, and implementing dark mode by overriding only semantic tokens under the .dark class. Next up we build the component library using these tokens.

Preguntas frecuentes

¿La lección «Crear la capa de tokens y configuración» es gratis?

Sí — el texto completo de «Crear la capa de tokens y configuración» es gratis para leer aquí en la web. Para practicarla de forma interactiva (editor de código integrado y tutor de IA 24/7) y desbloquear el resto del curso de Tailwind CSS Academy, actualiza a CoddyKit PRO. El curso de Tailwind CSS Academy incluye 4 lecciones en total.

¿Qué aprenderé en «Crear la capa de tokens y configuración»?

Implemente sus tokens de diseño como variables CSS, conéctelos a la configuración de Tailwind y pruébelos en los modos claro y oscuro. Practicas Tailwind CSS Academy con código real que ejecutas directamente en el navegador, y un tutor de IA 24/7 responde tus preguntas mientras trabajas en la lección.

¿Necesito experiencia previa para empezar Tailwind CSS Academy?

No se requiere experiencia previa. Tailwind CSS Academy en CoddyKit está estructurado para principiantes hasta estudiantes avanzados, así que puedes empezar aquí o desde el inicio y avanzar a tu ritmo. Esta es la lección 2 de 4.

¿Cuánto tiempo toma la lección «Crear la capa de tokens y configuración»?

La mayoría de las lecciones de CoddyKit toman alrededor de 5–10 minutos. Cada una es compacta e interactiva, así que avanzas constantemente y retomas exactamente por donde dejaste en la web y la app.

¿Puedo escribir y ejecutar código en esta lección de Tailwind CSS Academy?

Sí. Cada lección de Tailwind CSS Academy incluye un editor de código integrado, así que escribes y ejecutas código real directamente en tu navegador y obtienes retroalimentación instantánea de IA — sin configuración local necesaria.

Todas las lecciones de este curso

← Volver a Tailwind CSS Academy