Radial Tree of Countries Hierarchy
This radial tree visualization displays a hierarchical organization of countries grouped by continent and subregion, with the World at the root and individual nations as leaves. The code uses d3.cluster and d3.hierarchy to compute the radial layout, rendering SVG paths for links and text labels for nodes. Interactive panning and zooming is implemented with d3.zoom, while label rotation and font sizes vary by depth level. The data comes from a JSON file with nested children arrays, and the design includes a subtle glow effect on non-leaf labels.