This example displays the text “Hello React!” centered in a large font size. It serves as a minimal starter template for integrating React with a visualization environment. The application uses React and ReactDOM to render a single functional component, `App`, into the root DOM element. The page loads React and ReactDOM from external UMD scripts and mounts the component via `ReactDOM.render`, with styling applied through a CSS class. The code does not include any data visualization or interactive behavior.