This example renders a responsive smiley face using React and SVG, with the face sized relative to the browser window’s dimensions. The code positions a yellow circle as the head, centered via the `centerX` and `centerY` calculations, and adds two black eye circles offset by `eyeOffsetX` and `eyeOffsetY`. The SVG is generated directly in JSX, with React 16.9 handling the DOM updates and the root element mounted via `ReactDOM.render`. No external data is used; all geometry is derived from the window’s innerHeight and innerWidth.