This example shows a responsive smiley face rendered as a single SVG, with a yellow circular head, two black eyes, and a black stroke outline. The face is centered dynamically based on the browser window’s dimensions, and the eye positions and mouth radius are defined as constant offsets. The code uses React and ReactDOM to create SVG elements, with the `width` and `height` set to `window.innerWidth` and `window.innerHeight`. The face is drawn using `<circle>` elements, with the head’s radius dependent on the viewport height, ensuring it scales to fill the screen.