This example shows how D3.js can dynamically create and insert HTML elements, demonstrating basic DOM manipulation with a data-driven approach. The code uses `d3.select()` to target the `body` element, then appends a new `div` with `.append()`, and sets its text content with `.text()`. The div is styled using CSS rules embedded in the `<head>` of the document, setting a 40-pixel font size. The example relies on the D3 library loaded from a CDN, and represents a minimal starter template for anyone interested in integrating D3 v7 with a React framework.