This area chart displays CO₂ emissions across countries sorted by GDP per capita for 2025, using a monotone-curved blue fill. The visualization loads CSV data from a GitHub gist via `d3.csv`, then applies `d3.scalePoint` for the categorical x-axis and `d3.scaleLinear` for the y-axis. The `d3.area()` generator with `curveMonotoneX` renders the shaded region, while SVG axes with rotated country labels handle the presentation.