This example visualizes a choropleth map of the United States, displaying state-level unemployment rates with a green color scale derived from a TSV data file. Built with React and D3 v5, it renders state boundaries and graticules using `d3.geoPath` with an Albers projection, pulling TopoJSON data from the US Atlas. The React component hierarchy separates data loading in `useData` from map rendering in `Marks`, though the visualization currently displays a static map without completing the data-to-color binding.