World Countries Tree
This visualization presents a hierarchical tree of world countries, organized by region and subregion, using a left-to-right layout where each node is labeled with its region or country name. The tree is rendered as SVG with horizontal curved links, and labels scale in font size based on depth, from large root text to smaller country names. Built with D3 v5, it uses the `tree` and `hierarchy` layouts, `linkHorizontal` for path generation, and a `zoom` behavior for panning and scaling the view. Data comes from a local `data.json` file.