Stacked bar chart displays sales totals per product sub-category, segmented by customer segment. The visualization uses D3.js with SVG and animated transitions. Data comes from a CSV file containing order records. Hovering over the color legend highlights a specific segment by dimming other layers with a semi-transparent overlay. Tooltips, powered by d3-tip, show exact values for each bar segment. Axis formatting and legend rendering use D3's SVG axis and d3-legend APIs.