This example demonstrates a minimal React application that renders a static "Hello React!" message centered on the page. The code imports React and ReactDOM, defines a simple functional component returning a div with the message, and mounts it to the root element via `ReactDOM.render`. It uses the production builds of React 16.10.0 and ReactDOM, with styling handled by a CSS class in the HTML file. No data or external libraries are involved beyond the core React APIs.