This example visualizes the Keeling Curve, showing atmospheric CO2 concentration over time as a scatterplot of individual measurements connected by a line. The chart displays each data point as a semi-transparent circle over a gray inner plot area, with time-based axes and labeled axes for year and CO2 concentration in parts per million. It uses D3's `scaleTime`, `scaleLinear`, `line`, and `axisLeft` to render the visualization, with the data imported from the `@subh3ndu/keeling-curve` package.