This area chart visualizes the relationship between screen size and battery life for mobile devices, grouped by category. It uses stacked, semi-transparent areas with a monotone curve to show how battery life varies across screen sizes for each category. The visualization is built with D3 v7, loading CSV data from a GitHub gist and rendering as SVG. It includes axes for screen size and battery life, plus a legend, using `d3.area`, `d3.scaleLinear`, and `d3.schemeTableau10` for coloring.