This example shows a minimal React-based setup that renders a single circle in an SVG container and logs messages to the console. The page displays a large “Hello HTML!” message alongside the SVG, demonstrating basic DOM manipulation with D3.js. The code uses `d3.select` to target the SVG element and appends a circle with specified `cx`, `cy`, and `r` attributes. A separate CSS file styles the message and removes default body margins, while the HTML file links the stylesheet and loads the bundled JavaScript.