This choropleth map presents world countries colored by economic classification, with an interactive color legend that filters highlighted regions on click and hover. Users can zoom and pan the map, while clicking a legend category dims non-matching countries and re-clicking clears the filter. Built with D3 v5, it uses `d3.geoNaturalEarth1` and `d3.geoPath` for map projection, `d3.zoom` for navigation, and `d3.scaleOrdinal` with `schemeSpectral` for coloring. Data comes from the World Atlas TopoJSON and TSV files, rendered as SVG paths with tooltips.