This interactive visualization depicts the hierarchical structure of Wikipedia categories and pages as a tree diagram. Nodes are colored on a gradient from white to purple based on a group value, and hovering reveals a node’s name and whether an English version exists. Built with D3 v5, it uses `d3.tree` and `d3.hierarchy` for layout, `d3.zoom` for panning, and SVG circles and paths for rendering. Data is loaded from a local `data.json` file.