This interactive circle packing visualization displays a medical dataset as a hierarchical arrangement of nested circles, where each node represents a category or item and its size corresponds to its value. Users can click on any circle to zoom into that subtree, with the view smoothly animating to focus on the selected level. Built with D3.js v4 and React, the visualization uses the `d3.pack()` layout algorithm, `d3.hierarchy()` for data structuring, and `d3.interpolateZoom()` for the zoom transitions. Node colors are assigned via a linear scale with HCL interpolation based on hierarchy depth. The visualization loads its data from a remote JSON file hosted on GitHub.