This stacked bar chart visualizes the sales distribution of office supply subcategories across three market segments (Consumer, Corporate, Home Office). The D3.js visualization uses `d3.layout.stack()` to layer bars by subcategory within each segment, with hover interactions powered by `d3-tip` for tooltips. A color legend highlights individual subcategories on hover, while the axis formatting uses custom SI tick labels. The animated rendering and data aggregation from the CSV files demonstrate hierarchical grouping and stacked layout techniques in D3.