D3 v5 Zoomable Sunburst
This zoomable sunburst visualization displays a hierarchical dataset of energy and capital categories, allowing users to click arcs to focus on a child node and its descendants or click the center circle to zoom back out. Rendered as an SVG using D3 v5, the chart uses `d3.partition`, `d3.hierarchy`, `d3.arc`, and a color scale based on `d3.interpolateRainbow`. Transitions between zoom levels are animated via `transition.attrTween` and `d3.interpolate`, with labels and arcs fading based on visibility. The data originates from the Observable `@observablehq/flare` dataset.