A stacked area chart visualizes changes in numerical values across categories over time, using a dataset with multiple numeric columns and a year field. D3 v6 loads the CSV from a GitHub-hosted example, then uses `d3.stack()` to aggregate the series and `d3.area()` with scaleTime and scaleLinear axes to render the SVG paths. Each category is filled with a distinct color from a custom palette, with axes labeled "Year" and "Points??".