This example demonstrates a minimal React application that renders the text “Hello React!” on a blank page. It combines React 17 with D3 v6, loading both libraries in the HTML and creating a root component within the `#root` element. The code illustrates the basic integration setup, where `ReactDOM.render` mounts a simple functional component, and the page’s body is styled with zero margin and hidden overflow. No data visualization or D3 API is used beyond the initial import.