This example displays a yellow smiley face in SVG, with black-outlined circular eyes, a smiling mouth arc, and a black stroke, all centered and scaled to the browser window. Built with React and D3 v7, it uses the `d3.arc()` API to generate the mouth’s path, with geometric values like `eyeOffsetX`, `eyeOffsetY`, and `mouthRadius` defining the face’s proportions. The face is rendered reactively using `window.innerWidth` and `window.innerHeight` for full-window sizing, with all elements positioned inside a `g` transform.