A choropleth map colors world countries by economic grouping, using a spectral color scale and an accompanying legend. Built with D3 v5 and TopoJSON, it loads country boundaries and metadata from the world-atlas package. The map renders as SVG paths via `d3.geoPath` with a natural Earth projection, supports zooming through `d3.zoom`, and highlights countries on hover. The color legend is a custom component using `d3.scaleOrdinal` and `d3.schemeSpectral`.