This example demonstrates a hierarchical tree visualization of world regions and countries, arranged in a structured layout with labeled nodes. The visualization shows the geographic hierarchy from continents down to individual countries, with each text node sized according to its depth in the tree. The code uses D3.js v5 APIs including `tree()`, `hierarchy()`, `linkHorizontal()`, and `zoom()` to compute the layout, draw the connecting paths, and provide interactive zooming. Data comes from a local `data.json` file with region and country names, rendered as SVG elements with custom text shadow styling.