This area chart displays expense amounts by subcategory, using a steelblue filled area beneath a solid line. The visualization loads a CSV dataset via D3’s `d3.csv` fetch, maps subcategories to a point scale on the x-axis and amounts to a linear scale on the y-axis, and generates the area and line paths with `d3.area` and `d3.line`. Rotated x-axis labels and axis annotations are added with `d3.axisBottom` and `d3.axisLeft`, all rendered as SVG within an HTML canvas.