This interactive treemap visualizes stock expiration data from a CSV, using rectangle size to represent quantities and color to encode alert levels. The hierarchical layout, built with `d3.hierarchy` and `d3.treemap`, lets users click through levels from brand to item to lot. A custom tooltip, styled with CSS and shown on hover, displays detailed metrics like remaining days and lot percentages. The chart uses SVG rendering and smooth transitions via D3’s animation capabilities, with color scales defined per hierarchy level.