D3 v5 Zoomable Sunburst
This zoomable sunburst visualization displays the hierarchical Flare dataset, showing the relative sizes of categories and their subcomponents through concentric, color-coded arcs. Users can click on any segment to zoom into that branch, with animated transitions expanding and rotating the view around the central circle. The code uses D3 v5's `d3.hierarchy`, `d3.partition`, and custom `d3.arc` generators to draw SVG paths, while `transition.attrTween` and `d3.interpolate` handle the smooth geometric morphing between views. Data loads from the `@observablehq/flare` package via the Observable stdlib's `require` module.