This example shows the progression of total COVID-19 cases over time using a filled area chart. The chart plots dates on the x-axis and case counts on the y-axis, with a steelblue area beneath the line and circular markers on each data point. The visualization uses d3.csv to load data, d3.scaleTime and d3.scaleLinear for axes, and d3.area to generate the path. Interactive tooltips appear on mouseover via D3's transition and style methods, while the SVG rendering includes rotated tick labels and axis annotations.