A choropleth map of the world colors each country according to its economic classification, with a color legend on the left. The map uses a natural Earth projection rendered with `d3.geoPath`, and country data comes from the `world-atlas` TopoJSON and TSV files. A sequential color scale based on `d3.scaleOrdinal` and `schemeSpectral` assigns hues, and hovering turns a country red via SVG CSS. The visualization is built with D3 v5 and the `topojson` library's `feature` function, with zoom capability via a custom `zoom` callback.