This bubble chart displays hierarchical data as a packed circle layout, with each bubble sized by a logarithmic scale and colored by category. The visualization uses D3 v7’s `d3.hierarchy` and `d3.pack` to compute the layout, rendering SVG circles and text labels for each node. Tooltips show the full ID and category on hover, while a color legend built with a custom `colorScale` function explains the category mapping. Data is loaded from a CSV via `d3.csv`.