A React-based SVG smiley face renders across the full browser window, centered on the viewport. The face consists of a yellow circle with a black stroke, two black eyes positioned symmetrically, and no mouth. Using React 16.9 and ReactDOM, the component computes dimensions from `window.innerWidth` and `window.innerHeight`, then applies a translate transform via SVG `<g>` to center the drawing. All shape properties like radius and offsets are defined as constants.