A choropleth map visualizes national happiness scores by coloring countries according to their economy classification from the World Happiness Report CSV. The map uses a natural Earth projection via `d3.geoPath` and `d3.geoNaturalEarth1`, with color mapping through `d3.scaleOrdinal` and the spectral scheme. A custom legend component shows color categories, while zoom functionality is implemented with `d3.zoom`. Countries display tooltips with their name and economy type, and hover states change fill color to red.