This example visualizes a network graph of eight named nodes connected by seven links, with two large main nodes and smaller child nodes. A force-directed layout using `d3.forceSimulation` with `forceManyBody`, `forceLink`, and `forceCenter` positions the nodes, while SVG circles, lines, and text labels render the structure. Node colors and sizes are assigned from a separate color module, and dragging is enabled via the D3 drag behavior.