This fork of D3 v5's area chart displays life expectancy (labeled "cases") in the USA over time, using a green filled area under a basis-smoothed curve. The SVG chart uses `d3.scaleTime` for the x-axis and `d3.scaleLinear` for the y-axis, with axis labels and grid lines via `d3.axisBottom` and `d3.axisLeft`. Data is loaded from a GitHub-hosted CSV file, with the y-axis formatted using `d3.format`.