A yellow smiley face rendered as a full-screen SVG, scaled dynamically to fit the browser window. The face uses a large yellow circle with a black outline, two black eye circles, and omits a mouth. Built with React and ReactDOM, the component computes dimensions from `window.innerWidth` and `window.innerHeight` to position elements relative to the viewport center. The SVG uses nested `<circle>` elements within a transformed `<g>` group to handle responsive sizing.