This example demonstrates a full-screen layout divided into four colored panels using Bootstrap’s grid system. The page structure consists of two columns, each containing two rows, with each panel filled by a background color class (danger, info, secondary, warning). The code applies d3.v5’s `select` function from the `d3` module to target the SVG element and sets its width and height to match the browser viewport dimensions. The panel arrangement is entirely static, with the Bootstrap classes defining the visual hierarchy.