This example renders a centered message, “D3 template,” inside a React application. It uses React 16 and ReactDOM to create a single functional component that outputs a styled div. The implementation combines React’s JSX syntax with plain CSS for layout and typography, demonstrating a minimal setup where React manages the DOM while D3 is not yet integrated. The source code relies on UMD builds of react and react-dom loaded from unpkg, with the app bundled into a separate bundle.js file.