This example shows a horizontal tree diagram of technology domains, with three levels of depth branching from a root "Technology" node into categories like Programming Languages, Web Technologies, and Data & AI, and further into specific tools and languages. The visualization uses D3.js v7 with the `d3.hierarchy` and `d3.tree` layout APIs to compute node positions, and `d3.linkHorizontal` to draw smooth curved links between parent and child nodes. The SVG rendering distinguishes node hierarchy levels through color-coded fills: orange for the root, blue for first-level children, and green for second-level nodes, with each leaf labeled in small text.