This area chart visualizes insurance charges across different ages, using data fetched from a GitHub-hosted CSV file. The chart displays age on the x-axis and charges on the y-axis, with axis labels included for clarity. Built with D3 v7 and rendered as SVG, the visualization uses `d3.area()` to create the filled region and `d3.axisBottom` and `d3.axisLeft` for the axes. A tooltip, implemented with D3's selection and pointer methods, appears on mouseover to show the age and charges of the nearest data point.