Set up Master CSS in React

Guide to setting up Master CSS in your React project.

Master CSS Runtime Rendering observes changes in DOM class names at browser runtime, generates corresponding CSS rules, and injects them into the running style sheet.

Fixed style cost

All features work out of the box with ~16KB transfer cost

Fully automatic

Capture any program-generated class names

CSS lifecycle

CSS is generated on demand and frees memory when not in use

Quick start

Clone the example

Copy-paste the following commands to quickly start using the

You can skip all installation steps.

npx degit master-co/css/examples/react-with-runtime-rendering my-project
cd my-project
npm install @master/css.react@beta
npm install
npm run dev


Create a project

If you don't have a React project, create one first. It's recommended to refer to Start a New React Project.

npm create vite@latest project -- --template react-ts
cd project

Install Master CSS

Install Master CSS into your project via package managers.

npm install @master/css.react@beta

Initialize configuration file

Run npx mcss init to create a configuration file master.css.ts.

npx mcss init

Set up CSS runtime engine

  • Import your custom configuration master.css.ts
  • Initialize the runtime engine using CSSProvider
  • Add display: none in <html> to avoid FOUC
import React from 'react'
import ReactDOM from 'react-dom/client'
import App from './App'
import './index.css'
import { CSSProvider } from '@master/css.react'
import config from '../master.css'
ReactDOM.createRoot(document.getElementById('root') as HTMLElement).render(
<CSSProvider config={config}>
<App />

Avoid flash of unstyled content

Add display: 'none' in <html> to avoid FOUC caused by the runtime engine not yet injecting CSS rules.

<!DOCTYPE html>
<html lang="en" style="display: none">

Launch server

Run the Vite development server.

npm run dev -- --open

Hello world!

Now style your first element using Master CSS syntax!

export default function App() {
return (
<h1 className="font:40 font:heavy italic m:50 text:center">Hello World</h1>

Open your browser to watch the changes.


Hello World

MIT License © Aoyue Design LLC.