This example presents a minimalist blank canvas: a single rounded rectangle fills the entire browser window as a static SVG shape. The visualization demonstrates the basic setup of an SVG-based D3 scene, sizing the drawing area to the viewport and rendering one straightforward geometric element. The code uses D3 v5's `select` function to target the SVG element, then appends a rectangle with a 40-pixel corner radius, with the page styled to remove margins and prevent scrolling.