W3Schools Tryit Editor

main.jsx

index.html

import React from 'react';
import ReactDOM from 'react-dom/client';
import styles from './mystyle.module.css'; 

class Car extends React.Component {
  render() {
    return <h1 className={styles.bigblue}>Hello Car!</h1>;
  }
}

export default Car;

<!doctype html>
<html lang="en">
  <body>
    <div id="root"></div>
    <script type="module" src="/src/main.jsx"></script>
  </body>
</html>