Let's make a map with D3.js!
This example shows a simple world map rendered as an SVG, with countries filled in light green against a blue ocean sphere. The code uses D3 v5’s `geoMercator` projection and `geoPath` to draw geographic features, while TopoJSON’s `feature` method extracts country boundaries from the world-atlas dataset. Country paths are appended dynamically after loading the 110m resolution GeoJSON via a promise, with styling applied through CSS classes.