A smiling face is rendered as a fully responsive SVG using React components and D3’s `arc` generator. The face fills the browser window, with yellow circular head, black stroke, two eye circles, and a mouth path created via `d3.arc` with specified inner/outer radii and start/end angles. React handles the SVG element structure, while D3 computes the mouth’s path data. The viewport dimensions determine the head’s radius, centering it dynamically. The example demonstrates combining React’s declarative UI with D3’s geometric utilities for static SVG visualization.