This interactive pie chart shows the distribution of bike stations by municipality, with each slice labeled and colored. The visualization is built with D3 v6 and uses `d3.rollup` to group and count stations from a CSV file, then `d3.pie` and `d3.arc` to generate the slices. Hovering over a slice reveals a tooltip with the municipality name and station count. The chart renders as SVG with smooth opacity transitions for the tooltip, and the layout is centered using a translation on the SVG group element.