This example demonstrates a linked dataset of monthly S&P 500 index prices from a CSV file, presented as a brushable area chart. Users can adjust the visible time range by dragging a brush in the lower context panel, which updates the main focus chart’s x-axis domain. The code uses `d3.brushX` for selection, `d3.zoom` for panning, and `d3.area` with `d3.curveMonotoneX` to render the paths. Both charts are drawn in SVG with axes generated by `d3.axisBottom` and `d3.axisLeft`.