This example presents a minimalist blank canvas: a single, large rounded rectangle that fills the entire browser window. The visualization demonstrates a foundational D3 setup, using the `select` method to target an SVG element and dynamically setting its width and height attributes based on the viewport dimensions. It relies on the SVG rendering approach, appending a rectangle with `rx` for rounded corners. The code uses D3 v5, and the simple styles.css configures the body for a fixed, edge-to-edge display.