A choropleth map colors countries by economic classification using an ordinal color scale applied via `d3.scaleOrdinal` and `d3.schemeSpectral`. The map renders with `d3.geoPath` and a Natural Earth projection, drawing country boundaries from TopoJSON data loaded from the World Atlas. Hovering highlights a country in red, and a custom color legend built with reusable D3 code shows the category colors. The visualization supports zoom and pan through `d3.zoom`, with all elements rendered as SVG.