D3 v5 Zoomable Sunburst
This interactive sunburst diagram shows the hierarchical structure of the Flare dataset, with each ring segment representing a category and its value. Users can click on any segment to zoom in and focus on that branch, while clicking the central circle returns to the parent level. Built with D3 v5, the visualization uses `d3.hierarchy`, `d3.partition`, and animated SVG transitions to smoothly interpolate arc paths and labels via `transition.attrTween`. Data is loaded from the `@observablehq/flare` module, and colors are assigned using `d3.scaleOrdinal` with a quantized rainbow palette.