This example demonstrates a minimal integration of React and D3, displaying the text "Hello D3 & React" in a large, centered message. The code uses React's `useRef` and `useEffect` hooks to manage a DOM reference, then calls D3's `select` method to update the text content of that element. It loads React 19 and D3 v7 via import maps and renders the application through `createRoot`. The visualization shows how to combine React's component-based rendering with D3's DOM manipulation utilities.