This example uses React and ReactDOM to render a scalable SVG smiley face that fills the entire browser window. The face is constructed from three circles—a yellow head with a black outline and two black eyes—positioned relative to the window’s center. The SVG dimensions and all element coordinates are computed dynamically from `window.innerWidth` and `window.innerHeight`, with the mouth commented out in the HTML. The drawing is generated live in the browser, with no external data source.