This example visualizes a hierarchical dataset of food categories—Food, Fruits, Vegetables, and Grains—as a vertical tree. It shows the nested structure with color-coded nodes by depth: blue for the root, orange for first-level children, and green for leaves, with links as curved paths. Built with D3.js v7, it uses `d3.hierarchy` and `d3.tree` to compute the layout, `d3.linkVertical` for the connecting paths, and SVG circles and text for node rendering. The hardcoded data is displayed in a 600×400 SVG.