This example shows a full-window smiley face rendered with React and SVG. The face adapts to the browser viewport, centering its circular head and positioning two eyes symmetrically around the center using static offset values. The code uses React 16.9.0 to create SVG elements, including a yellow circle with a black stroke for the head and two plain black circles for the eyes. The rendering approach relies on ReactDOM to mount the component into the DOM, with dimensions calculated from `window.innerWidth` and `window.innerHeight`.