This area chart displays the average age of diabetic patients over time, using a red filled curve to emphasize the trend. The visualization loads CSV data via `d3.csv` and renders an SVG using D3 v5, with `scaleTime` and `scaleLinear` for axes. It employs `d3.area` with a `curveBasis` smoothing function, styled through external CSS. Axis labels and a title are added using SVG text elements, with tick formatting applied via `d3.format`. The data source is a remote gist, and the chart includes custom margins and gridlines.