Responding to Resize
This example demonstrates how a D3.js visualization can respond dynamically to browser resizing, drawing a pair of green, semi-transparent diagonal lines that form an X spanning an SVG element. The chart fills the viewport using CSS fixed positioning, and a `redraw` function reads the container’s `clientWidth` and `clientHeight` to update the SVG’s dimensions and line coordinates. The code uses D3 v5 selections and the `window` resize event listener to trigger a redraw whenever the window size changes, ensuring the visual always fits its container.