An interactive sunburst chart visualizes Beijing’s daily COVID-19 case increases from February to March. The D3.js partition layout renders hierarchical flare data as radial arcs, colored by category and animated on click to zoom into nested branches. Built with `d3.partition`, `d3.hierarchy`, and `d3.scaleOrdinal`, it uses SVG `path` tweens via `transition.attrTween` for smooth transitions. Font sizes and arc visibility adapt through computed label thresholds, while the top-level root circle resets the view.