This example renders a choropleth-style map of continental Costa Rican cantons using a Mercator projection. It loads GeoJSON data via `d3.json` and draws the geographic features as SVG paths with `d3.geoPath` and `d3.geoMercator`. The code binds the fetched features to path elements, generating each shape’s outline directly from the GeoJSON geometry. The map uses a minimal styling approach with a full-window SVG and no additional data-encoding layers.