A blank, rounded rectangle fills the browser viewport, adapting to the full dimensions of the window. The visualization is a minimalist canvas, rendered as a single SVG rectangle with no data plotted. It uses D3 v6's `select` and `attr` methods to size the SVG element against the body’s `clientWidth` and `clientHeight`, directly appending a `rect` with rounded corners. The piece demonstrates a foundational, empty state for a data-driven graphic.