World Countries Tree
This visualization presents a hierarchical tree of text labels, rendering world countries and related terms as interconnected nodes. Users can pan and zoom the SVG canvas via mouse events. The code loads hierarchical data from a JSON file, applies D3's `tree` layout and `hierarchy` function, and draws curved links with `linkHorizontal`. Node labels display their `id` values with font sizes that shrink with depth, styled using the Playfair Display font. The visualization omits visual node markers, showing only connecting paths and text labels.