This visualization displays song popularity and genre using a bubble chart, with each bubble sized by popularity and colored by genre according to a Tableau10 ordinal scale. The chart packs hierarchical leaves via `d3.pack` and renders SVG circles, labels, and tooltips from a CSV dataset. A legend built with custom selection methods shows genre color mappings. The code uses D3 v7 APIs including `d3.hierarchy`, `d3.map`, `d3.InternSet`, and `d3.scaleOrdinal`.