This example shows an interactive family tree diagram for the Kohli family, with nodes representing individuals and links showing parent-child relationships. Users can click on nodes to collapse or expand branches, with animated transitions smoothly repositioning elements. The visualization uses the D3.js library's tree layout and diagonal path generator to structure the SVG rendering, while custom CSS styles green node circles and connecting lines. The tree data is hardcoded in a JavaScript array, and the collapse/expand behavior leverages D3's standard enter-update-exit pattern with transition methods.