This example demonstrates a minimal D3.js application that renders a text message to the page. It shows how to import functions from the D3 library and from local ES6 modules, using `d3.select` to target a div element and set its text content. The message originates from a separate JavaScript file, while CSS styles center the text and enlarge it to 12em. D3 v5 is loaded via UNPKG, and the code follows a modular structure with separate index and message modules.