This network graph visualizes a hierarchical dataset of global health concerns, grouping diseases by country and category. Force-directed layout positions nodes, revealing clusters while color encodes depth: orange for countries, light blue for categories, and green for diseases. The D3.js v7 simulation uses `d3.forceSimulation`, `d3.forceLink`, `d3.forceManyBody`, and `d3.forceCenter` forces. Nodes are draggable via a custom `drag` function, with SVG `circle`, `line`, and `text` elements updating positions on each tick.