This example shows a minimal integration of React and D3, displaying the text "Hello D3 & React" in a large, centered message. The code uses a `useRef` hook to attach a D3 selection to a div, then calls `select().text()` inside a `useEffect` to update the DOM. React 19 manages the component lifecycle, while D3 v7 handles the selection and text manipulation, demonstrating a simple pattern for combining the two libraries in a single page.