An interactive choropleth map of European fuel prices lets users hover over countries to view prices, click to pin a country, and edit its price values directly. A fuel-type selector switches between Euro 95, Diesel, and LPG datasets, driving an SVG map built with `d3.geoMercator` and `d3.geoPath`. Country boundaries are filtered from a GeoJSON source, and a custom color scale generated by `d3.scaleLinear` maps prices from green to red, with a legend showing the gradient range.