This interactive choropleth map colors countries by economic classification, with a hover effect that turns each country red and a custom color legend showing the categorical scale. Built with D3 v5, it uses `geoNaturalEarth1` and `geoPath` for map projections and rendering, while `scaleOrdinal` and `schemeSpectral` assign colors. The map loads world geometry from the world-atlas TopoJSON and TSV files, and supports zooming via the `zoom` event, which updates the SVG group’s transform.