This area chart visualizes the relationship between fuel efficiency and engine size for a car dataset loaded from a GitHub-hosted CSV file. The chart uses `d3.area` to generate a filled path, with `d3.scaleLinear` for both axes and `d3.axisBottom`/`d3.axisLeft` for tick marks. The SVG rendering displays a semi-transparent steelblue region, with labeled axes for "Fuel Efficiency" and "Engine Size". Data values are parsed from strings to numbers before domain scaling, and the area’s baseline is set to the chart’s height.