A choropleth map of 2020 US state population estimates uses a linear color scale from light gray to teal to encode population values. The visualization loads state population data from a CSV and US state boundaries from GeoJSON, then merges them by state name. It renders the map using d3.geoPath with the d3.geoAlbersUsa projection, and includes a vertical legend built with d3.legendColor. The SVG output is responsive and styled with a custom CSS file.