This circle-packing diagram visualizes the hierarchical structure of the Flare dataset, with nested circles representing categories and subcategories. Circle size encodes the summed value of each node. The visualization uses D3 v5’s `d3.stratify` and `d3.pack` to compute the layout, and `d3.scaleSequential` with `d3.interpolateMagma` to color circles by depth. Hovering highlights a node’s ancestors using the `d3.selectAll` and class toggling. SVG renders all elements, with leaf labels clipped via `clipPath`.