This choropleth map shows population density across Croatian counties, with the city of Zagreb standing out as the most densely populated area. The visualization uses a red color scale with nine bins to represent density ranges, and hovering over a county reveals its name, population, and density per square kilometer. The map is rendered with SVG and built using D3.js v6, employing `d3.geoMercator` for projection and `d3.geoPath` for drawing the geographic features from TopoJSON data. A color legend is manually constructed using `d3.scaleLinear` and `d3.schemeReds`.