This example displays the text “Hello React!” in a large, centered font on a plain white page. It demonstrates a minimal React setup, using `React` and `ReactDOM` from the React 16.10.0 UMD builds to render a single functional component into a `div` with the ID `root`. The component returns a JSX element styled with a 13em font size via a CSS class, illustrating basic component creation and DOM mounting without additional libraries.