This example shows a technology learning tree with a root “Tech” node branching into three skill categories—AI, Web Development, and Cybersecurity—each with three leaf skills. It renders a hierarchical tree using the d3.hierarchy and d3.tree layout APIs, drawing links with d3.linkHorizontal and color-coding circles by depth. The SVG is built with D3 v7 and styled with inline attributes, displaying all data from a hardcoded JavaScript object.