This example shows a pie chart of CSS named colors, with each slice colored by the RGB hex value loaded from a CSV file. The visualization uses React’s `useState` and `useEffect` hooks to fetch and store the data via `d3.csv`, then computes pie arcs with `d3.arc` and renders the result as SVG paths. While the data loads, a loading message appears; afterward, the full pie chart displays. The code relies on D3 v6 for data parsing and geometry, and React 16.9 for component state and rendering.