This example displays an animal classification hierarchy as a tidy tree layout, showing the relationships from “Animals” down to individual species such as Dog, Eagle, and Snake. The visualization uses D3 v7’s `d3.stratify` to convert flat CSV data into a hierarchy, then applies the `d3.tree` layout to position nodes. Links are drawn as horizontal paths using `d3.linkHorizontal`, while nodes are rendered as colored circles scaled by depth, with labels adjacent to each circle.