This stacked bar chart displays total brand sales in millions of dollars, broken down by region, using a Tableau10 color scheme to distinguish each region. D3.js (v7) loads CSV data from a GitHub gist, groups and aggregates sales per brand and region, then renders the visualization as SVG. The chart uses `d3.stack` for stacking, `d3.scaleBand` for the x-axis, `d3.scaleLinear` for the y-axis, and includes rotated brand labels, axis titles, and a legend.