This choropleth map shows estimated country populations for 2023, with darker blue-green shades representing higher population counts and gray indicating missing data. It uses a Natural Earth projection via `d3.geoNaturalEarth1` and renders country boundaries with `d3.geoPath` from TopoJSON data loaded with `d3.json`. Population values from a CSV file are mapped to a sequential color scale, and hover tooltips display each country’s name and population. A gradient legend with a linear scale shows the population range, all rendered as SVG using d3.v7.