This network graph visualizes relationships between cardiovascular diseases, with a central node for Cardiovascular Diseases branching into categories like Arrhythmias and Aneurysms, which further connect to specific conditions. The force-directed layout uses `d3.forceSimulation` with `forceLink`, `forceManyBody`, `forceCollide`, and `forceCenter` to position nodes. Data loads from a JSON file, and SVG circles represent nodes while lines with arrow markers show directed links. The code employs D3 v6 methods such as `select`, `scaleOrdinal`, and drag interactions to enable node movement and highlighting on mouseover.