A stacked bar chart displays monthly sales across three product categories—Electronics, Clothing, and Groceries—using data from data1.csv. The visualization uses D3.v7 to render SVG rectangles with distinct color encoding per category, and includes interactive tooltips that reveal exact values on hover. Axes are generated with `d3.axisBottom` and `d3.axisLeft`, while the `d3.stack` utility computes cumulative bar heights for the layered presentation, with a legend clarifying category colors.