This multiline chart compares profit across product sub-categories for different regions, using color to distinguish each region. Built with D3 v5, it renders an SVG with a time-scaled x-axis, linear y-axis, and a legend via the custom `colorLegend` function. Data is loaded from a CSV file and processed with `d3.nest()`, then lines are drawn using `d3.line()` with `curveBasis` smoothing.