This example demonstrates the simplest possible D3 visualization, rendering the text "Hello D3 ver. 6" directly into the page body. It uses D3’s `select` method to target the `body` element and set its text content. The page also includes a separate script that logs "Hello JavaScript!" to the browser console, while CSS centers the text at a large font size. The code relies on the d3.v6 library loaded from a CDN, with the main logic in `index.js`.