This choropleth map visualizes the prevalence of HIV/AIDS among adults aged 15–49 by country for the year 2017. The color of each country reflects its value using a sequential yellow-orange-red color scale, with missing data shown in gray. The map is rendered with `d3.geoPath` and `geoNaturalEarth1` projection, while country boundaries and graticules come from a TopoJSON world atlas. React manages the component structure, and the data is loaded from a CSV file using `d3.csv`.