This example displays a choropleth-style map of Swedish counties, with each county filled in aqua and outlined in red, while shared interior borders appear in teal. The visualization uses a geoMercator projection fitted to the geographic data via `projection.fitExtent`. Built with React and D3 v5, it leverages `d3.geoPath` to render SVG paths from TopoJSON data, styled through CSS class selectors and framed by a simple SVG container.