This example shows a minimal React application that renders the text “Hello React!” in large, centered type. It demonstrates the basic structure of a React component and how to mount it into the DOM. The code uses the React and ReactDOM libraries, with the `App` component defined as a functional component and rendered via `ReactDOM.render` into a root div. The HTML file loads React and ReactDOM from a CDN, while the JavaScript file uses JSX to define the component’s markup.