This stacked bar chart visualizes sales costs aggregated by department, item category, and sales type using a hardcoded dataset. The chart groups bars by department, with sub-bars representing item categories and segments distinguishing domestic versus international sales. It uses D3.js v7 with SVG rendering, leveraging `d3.group` for data aggregation and `d3.scaleBand` and `d3.scaleLinear` for positioning. Color scales differentiate departments across sales types, while axes and labels clarify the department and cost dimensions, though international segments are stacked alongside domestic totals.