A choropleth map colors world countries by economy type, with a color legend and hover highlight. It renders GeoJSON country paths using `d3.geoPath` with a `geoNaturalEarth1` projection, and supports pan and zoom via `d3.zoom`. Data comes from TopoJSON world-atlas files and CSV metadata joined by ISO code; `scaleOrdinal` assigns categorical colors from `schemeSpectral`, and the legend is built with D3 selections.