This example displays a large, centered “Hello React!” message rendered as plain text. It demonstrates the minimal setup for a React application, using React 16.10.0 and ReactDOM to mount a functional component called `App` into a `div` with the ID `root`. The component returns a `div` with a CSS class that sets the font size to 13em and centers the text. The rendering approach relies on the production builds of `react` and `react-dom` loaded from unpkg, with `bundle.js` executing the render call.