Fork of Smiley Face Part II
This example displays a friendly yellow smiley face that fills the entire browser window, scaling its size responsively to the viewport dimensions. The face is constructed using React components that render SVG circles for the head, eyes, and facial features, with the head positioned at the center of the screen. The code imports the `arc` function from `d3` and uses D3 v7 for mathematical utilities, while React handles the SVG element creation and DOM updates. The implementation uses absolute positioning with `window.innerWidth` and `window.innerHeight` to determine the face’s dimensions, and applies a stroke to outline the head circle.