This example shows a full-screen smiley face rendered as a donut chart, with each slice colored by a hex value loaded from a remote CSV file. The React component uses the `useState` and `useEffect` hooks to fetch the data via `d3.csv`, then applies `d3.pie` and `d3.arc` to generate SVG path elements. The face’s features are implied by the circular pie layout, with the inner radius set to zero and the outer radius matching the viewport width.