Let's make a map with D3.js!
This example shows a world map rendered as SVG, with countries filled in light green and oceans depicted as a blue sphere. It loads GeoJSON country boundaries from the World Atlas TopoJSON dataset via `d3.json` and converts them using the TopoJSON `feature` function. The map is drawn with `d3.geoPath` and a `d3.geoNaturalEarth1` projection, adding a background sphere path for the ocean. Using D3 v5 and SVG, it demonstrates a straightforward choropleth-style basemap without interactivity.