This example demonstrates how a visualization can dynamically respond to browser window resizing. It uses the CSS `clientWidth` and `clientHeight` properties to extract the current container size and applies these dimensions to an SVG element via the `attr` method. Two diagonal lines are drawn across the SVG to visually confirm the correct sizing, with a resize event listener triggering a full redraw. The code relies on D3 v5’s selection and data join patterns to update the line coordinates.