This example demonstrates a minimal React application that renders a static message to the DOM. It uses React and ReactDOM to define an `App` component, which returns a div with the text “Hello React!” styled at a large font size. The `ReactDOM.render` method mounts the component into the `#root` element in `index.html`. React is loaded via UMD production builds from unpkg, and the application is bundled into `bundle.js` for execution.