Get your own React server
main.jsx
index.html
 
import { createRoot } from 'react-dom/client';
import styled from 'styled-components';

const MyHeader = styled.h1`
  padding: 10px 20px;
  background-color: #007bff;
  color: white;
`;

function App() {
  return (
    <>
      <MyHeader>Welcome!</MyHeader>
    </>
  );
}

createRoot(document.getElementById('root')).render(
  <App />
);

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

                    
localhost:5173