This choropleth map colors countries by their economy category using a spectral color scale, with a legend that filters the map by clicking on a category. The map renders with SVG paths via `d3.geoPath` and the Natural Earth projection, while the legend uses `d3.scaleOrdinal` and `d3.schemeSpectral` for color assignment. Interactive filtering dims non-selected countries and legend entries, and hovering reveals country names and values through SVG `title` elements. Country boundaries come from the world-atlas TopoJSON dataset merged with TSV metadata.