This area chart visualizes the total purchase amount in US dollars by customer age, using shopping trends data loaded from a CSV file via `d3.csv`. The chart applies `d3.rollup` to aggregate and sum purchases per age, then renders the result as an SVG path generated with `d3.area`. Axes are drawn using `d3.axisBottom` and `d3.axisLeft`, with linear scales (`d3.scaleLinear`) mapping age and purchase totals. A blue filled area with a darker stroke highlights the distribution, while axis labels clarify the variables.