A choropleth map colors world countries by their economy category using a spectral ordinal color scale, with an interactive color legend rendered as circles and labels. The visualization loads country geometries from TopoJSON and joins them with tabular metadata via a promise-based data pipeline. Rendered as SVG, it uses `d3.geoPath` with a Natural Earth projection and supports zooming through `d3.zoom`. Hovering highlights countries, while the legend is built using the exported `colorLegend` helper, with styling defined in external CSS.