This example presents a blank, rounded-corner rectangular canvas that fills the entire browser viewport. The visualization uses D3 v5 to create a single SVG `rect` element, with dimensions dynamically calculated from the `document.body.clientWidth` and `clientHeight` properties. The canvas is styled with a fixed, full-screen layout, and the D3 `select` function targets the SVG element to set its width and height, demonstrating a minimal setup for responsive SVG rendering.