This visualization displays fluctuations in the S&P 500 stock index over time, with a line chart showing price changes along a temporal axis. The example uses Vega-Lite’s JSON specification format to declare the chart, which is rendered through the vega-embed library within a minimal HTML page. The chart encodes dates on the x-axis and quantitative price values on the y-axis, while the mark type is set to "area" to fill the region beneath the line. The underlying data is fetched from a remote CSV hosted in a GitHub gist.