This example demonstrates the simplest possible D3 setup: a web page that displays the text “Hello D3 version 7” in the center of the viewport using a 13em font size. The page loads D3 v7 from a CDN and then runs a separate `bundle.js` file. The core code uses `d3.select('body').text(...)` to select the body element and set its text content, showcasing how to import named functions like `select` from the D3 library in a modular JavaScript file.