This example demonstrates the simplest possible setup for a data visualization using HyperText Markup Language (HTML), Cascading Style Sheets (CSS), and JavaScript. It renders an empty Scalable Vector Graphics (SVG) element and then uses the d3-selection module, via the `select` function from D3 v6, to change the SVG's background color to blue. The visualization shows how a basic web page can be structured with a separate stylesheet and script, providing a foundation for building more complex projects.