This example demonstrates a minimal React application that renders a centered "Hello React!" message in large text. The app uses React 16.13.1 and ReactDOM to mount a single functional component into a root div. The styling is applied through a CSS class that sets the font size and alignment, while the component itself contains only static text content. The code relies on the production builds of React and ReactDOM loaded via CDN, with the application logic compiled into a separate bundle.js file.