Two stacked area charts show the S&P 500 price over time, sourced from a CSV file. The upper chart’s x-axis scale is linked to a brush selection on the lower, smaller chart via a Vega-Lite parameter named `brush`, which uses an interval selection over the x-encoding. Dragging across the lower chart updates the upper chart’s displayed date range. The visualization is built with Vega-Lite 5, embedded by vega-embed, and renders area marks for both views.