A yellow smiley face is drawn as a full-screen SVG graphic, centered dynamically within the browser window. The face features two black-outlined eyes and a mouth, constructed with precise offsets and radii that scale with the viewport dimensions. Built with React and rendered as an SVG, the code uses ReactDOM to mount the component, calculating circle positions based on `window.innerWidth` and `window.innerHeight` to ensure the face remains centered. The face is defined by a solid yellow circle with a black stroke, with eye and mouth proportions calculated relative to the screen size.