This example visualizes music listening habits from a last.fm profile, showing stacked area charts of play counts per genre across the weeks of 2018. A color legend allows clicking to highlight or isolate a single genre, which re-renders the chart with smooth transitions. The visualization uses D3 v5 APIs including `d3.stack`, `d3.area`, `d3.scaleOrdinal`, and `d3.scaleLinear`, with SVG paths and animated transitions for interactivity. Data is loaded from a CSV and a nested JSON genre hierarchy, processed into weekly aggregates.