This example shows a minimal force-directed graph with three nodes and two links, rendered as SVG circles and lines. The simulation uses `d3.forceSimulation` with `forceManyBody`, `forceLink`, and `forceCenter` to position the nodes, while a `tick` event updates the circle and line coordinates. Data consists of hardcoded node IDs and link indices in `index.js`, styled with a large font size and hidden overflow via `index.css`. The code imports from D3 v6 and runs within a React-free HTML page, using a fixed 960×500 SVG viewport.