This interactive map shades countries by economic classification using a categorical color scale, with a clickable legend that filters the visible categories. The visualization uses d3.zoom for panning and zooming, d3.geoNaturalEarth1 with d3.geoPath for geographic projection, and SVG paths with title tooltips for hover details. Data comes from the world-atlas TopoJSON dataset joined with TSV metadata via d3.tsv and topojson.feature. The colorLegend module builds a custom SVG legend with circles and text, while CSS hover effects highlight individual countries.