This example visualizes the counties of Sweden as a choropleth-style map, with each region filled in a muted red and interior boundaries highlighted in teal. Built with React and D3 v5, it loads TopoJSON data from a GitHub gist and converts it to GeoJSON using `feature` and `mesh` from the topojson library. The map is rendered as SVG using `geoMercator` projection and `geoPath`, with a `fitExtent` call to scale the map to fit the viewport.