This example adapts the classic smiley face drawing into a responsive React component that fills the browser window. Using React 16.9 and ReactDOM, it renders an SVG with a yellow circle face, two black eye circles, and a mouth outline, all positioned relative to the viewport’s center. The code calculates dimensions dynamically from `window.innerWidth` and `window.innerHeight`, and applies a transform to center the drawing group. It demonstrates React’s declarative approach to SVG composition, with coordinates and radii stored as constants for easy adjustment.