This example renders a large, responsive smiley face centered on the screen using React and D3 v7. It shows how D3’s `arc()` generator creates the mouth path, while the eyes and blush are positioned with SVG circles using JSX. The face scales to the browser window’s dimensions, and the body margin is hidden for a full-viewport display. The code explicitly references React 16.9, ReactDOM, and D3’s `line()` generator, though the line is only a minimal placeholder.