A blank canvas fills the browser window, rendered as a single rounded rectangle using D3 v5's `select` and SVG `attr` methods. The visualization displays no data, only an empty, fixed-position SVG that adapts to the viewport's dimensions. The code imports `select` and `arc` from D3, though only `select` is used to create the static shape. The HTML loads `styles.css` for full-bleed layout and `bundle.js` to execute the drawing logic.