This example demonstrates a minimal integration of React and D3, rendering the text "Hello D3 & React" as a large, centered message. The code uses React's `useRef` and `useEffect` hooks to access the DOM node, then applies D3's `select` function to update its text content. It imports React 19 and D3 v7 via an import map, and renders the app through `react-dom/client`'s `createRoot`. The visualization serves as a starter template for combining React's declarative UI with D3's imperative DOM manipulation.