This example shows a React application that renders a simple text message, “Hello React!”, centered on the page. The code uses React and ReactDOM to define a functional component and mount it to the DOM. The styling is set via a CSS class in the HTML file, and the app is built with a bundled JavaScript file. It demonstrates the basic setup for a React visualization gallery starter, relying on React 16.10.0 and the `ReactDOM.render` API.