A stacked bar chart visualizes product sales across four categories, with each bar segment representing a category’s contribution to total sales for a given product. The chart encodes values on a linear x-axis and product names on a categorical y-axis, using color to distinguish categories. Built with D3 v7, it uses `d3.stack()` to compute stacked values, `d3.scaleBand()` for the y-axis, and `d3.scaleLinear()` for the x-axis. Data is loaded via `d3.csv()` from a local CSV file, and SVG rectangles render each segment with mouseover logging to the console.