TailwindCSS integration

Learn how to use TailwindCSS in Aurelia 2 with this detailed guide.

What is Tailwind CSS?

Tailwind CSS is a highly customizable, low-level CSS framework that gives you all of the building blocks you need to build bespoke designs without any annoying opinionated styles you have to fight to override.

For more information take a look at Tailwind CSS

How to configure an Aurelia 2 project with Tailwind CSS v4?

Tailwind CSS 4.1 introduces a simplified setup: install Tailwind, add the official plugin for your bundler, then import tailwindcss once inside your stylesheet. No @next tags, no tailwind.config.js (unless you want customizations), and no manual content paths.

Step 1: Create an Aurelia project

npx makes aurelia

Choose your preferred bundler. The steps below highlight Vite first, followed by Webpack, Parcel, and the standalone CLI.

Step 2: Install Tailwind packages

Vite (recommended)

npm install tailwindcss @tailwindcss/vite

Webpack

npm install tailwindcss @tailwindcss/postcss postcss postcss-loader

Parcel

npm install tailwindcss @tailwindcss/postcss

Standalone CLI / static builds

npm install tailwindcss @tailwindcss/cli

Step 3: Configure your bundler

Vite configuration

// vite.config.ts
import { defineConfig } from 'vite';
import aurelia from '@aurelia/vite-plugin';
import tailwindcss from '@tailwindcss/vite';

export default defineConfig({
  plugins: [aurelia(), tailwindcss()],
});

Webpack configuration

Create postcss.config.js:

export default {
  plugins: {
    '@tailwindcss/postcss': {},
  },
};

Update webpack.config.js so .css files run through postcss-loader:

module.exports = {
  module: {
    rules: [
      {
        test: /\.css$/,
        use: ['style-loader', 'css-loader', 'postcss-loader'],
      },
    ],
  },
};

Parcel configuration

Parcel reads PostCSS config automatically. Create .postcssrc:

{
  "plugins": {
    "@tailwindcss/postcss": {}
  }
}

CLI workflow

If you aren’t using a bundler, wire up the CLI directly:

npx @tailwindcss/cli -i ./src/input.css -o ./dist/tailwind.css --watch

The CLI watches your HTML entry file and any imports it discovers, so the build remains tree-shaken even without a config file.

Step 4: Import Tailwind once

Add this line to the top of your root stylesheet (for example src/my-app.css):

@import "tailwindcss";

This single import injects Tailwind’s base, component, and utility layers. The old @tailwind base; / @tailwind utilities; directives aren’t used in v4.

Step 5: Run the project

npm run dev

Tailwind’s compiler runs alongside your bundler, so editing Aurelia templates immediately updates the generated CSS.

---

How to test Tailwind styles quickly

Insert the following snippet into any view:

<div class="p-6">
  <div class="bg-red-100 border border-red-400 text-red-700 px-4 py-3 rounded relative" role="alert">
    <strong class="font-bold">Holy smokes!</strong>
    <span class="block sm:inline">Something seriously bad happened.</span>
    <span class="absolute top-0 bottom-0 right-0 px-4 py-3">
      <svg class="fill-current h-6 w-6 text-red-500" role="button" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><title>Close</title><path d="M14.348 14.849a1.2 1.2 0 0 1-1.697 0L10 11.819l-2.651 3.029a1.2 1.2 0 1 1-1.697-1.697l2.758-3.15-2.759-3.152a1.2 1.2 0 1 1 1.697-1.697L10 8.183l2.651-3.031a1.2 1.2 0 1 1 1.697 1.697l-2.758 3.152 2.758 3.15a1.2 1.2 0 0 1 0 1.698z"/></svg>
    </span>
  </div>
</div>

Seeing the styled alert confirms that Tailwind’s classes are available in your bundle.

---

Content detection & build optimization

Tailwind v4 automatically scans your project for class usage, removing unused styles during both dev and production builds. You no longer set content: [] in tailwind.config.js. If you need to extend the theme or register plugins, create a config manually:

/** @type {import('tailwindcss').Config} */
export default {
  content: ['./src/**/*.{html,ts}'],
  theme: {
    extend: {
      colors: {
        brand: '#8250df',
      },
    },
  },
  plugins: [],
};

During npm run build, Tailwind’s compiler and Lightning CSS minify the stylesheet and automatically add vendor prefixes.

---

Migrating from Tailwind v3

1. Replace the old @tailwind base/components/utilities directives with @import "tailwindcss";

2. Uninstall autoprefixer and postcss unless another tool in your stack needs them—Tailwind v4 handles prefixing internally.

3. Remove manual content arrays unless you want to override the automatic detection.

4. Install the new plugin for your bundler (@tailwindcss/vite, @tailwindcss/postcss, or @tailwindcss/cli).

After migrating, you benefit from zero-config tree shaking, smaller CSS bundles, and much faster incremental builds.