D3 v5 Zoomable Sunburst
This zoomable sunburst visualizes hierarchical data from the flare library, displaying nested categories as concentric rings where arc size encodes value. Clicking a node zooms into that subtree, with smooth transitions animated via `d3.transition` and `transition.attrTween`. The chart is built with D3 v5’s `d3.hierarchy`, `d3.partition`, and `d3.arc`, using SVG rendering with rainbow color scales. Labels rotate and fade based on visible arc size, and a central circle returns to the root view.