This example demonstrates a bare-bones HTML page for learning D3, combining vega, vega-lite, and D3 v7 scripts via a React starter template. The code loads multiple visualization libraries and renders a simple body with a root div, while applying custom CSS styling for a tooltip element. The page serves as a minimal foundation for practicing data visualization techniques, with no specific chart or simulation implemented. It primarily shows the setup required to integrate these libraries together in a single document.