This visualization shows a hierarchical dataset as a radial partition layout, or sunburst diagram, where each arc segment represents a node’s proportional value. Using D3 v5, the code constructs the layout with `d3.hierarchy`, `d3.partition`, and `d3.arc`, rendering SVG paths. The data is embedded directly in `index.js` rather than read from `data.csv`, with arcs styled via the `styles.css` file.