This example greets the viewer with a bold, full-screen “Hello D3 version 7” message in large type. The page uses a minimal setup with an HTML file that loads the D3 v7 library and a JavaScript file that calls `select` from D3 to target the body element. The text is set via the `.text()` method, with styling applied directly in the page’s CSS. No external data is involved; the focus is solely on demonstrating a basic D3 selection and DOM manipulation.