This chart visualizes project progress as an S-curve, comparing planned versus actual cumulative values over time, with milestone markers and a bar chart of monthly increments. It uses D3 v7 to render SVG elements including lines, areas, and rectangles. The implementation supports synchronized zooming and panning on both axes through d3.zoom, with separate zoom behaviors for X and Y. The data loads from a CSV file containing plan, actual, and date fields.