This chart shows the cumulative engagement of a social media dataset over time, using an area chart to visualize the growing total as a filled region. The visualization is rendered as SVG using D3 v7, with the x-axis representing dates and the y-axis showing the cumulative sum of engagement values. The code loads data from a CSV file, aggregates engagement by day using `d3.rollup` and `d3.sum`, then computes the running total. The area path is drawn with `d3.area` and a monotone curve, styled with a light blue fill and steel blue stroke, alongside axes labeled "Date" and "Cumulative Engagement".