This example demonstrates a zoomable, hover-highlighted world map using D3 v5. It renders country boundaries and a blue sphere backdrop via `d3.geoPath` with a Natural Earth projection, pulling geometry from the world-atlas TopoJSON dataset. The visualization supports interactive pan and zoom through `d3.zoom`, applying transforms to an SVG group, and changes country fill to red on hover via CSS. Country names are joined from a TSV file using ISO numeric IDs.