This example renders the text “Hello React!” centered on the page using a React functional component. The `App` component returns a `<div>` with the message styling defined in the `index.html` stylesheet. ReactDOM’s `render` method mounts the component to the `#root` element, while the UMD builds of React 16.10.0 and ReactDOM are loaded from unpkg. The visualization demonstrates a minimal setup for integrating React with a plain HTML page, relying solely on React’s component-based rendering rather than any data or interactive features.