This pie chart visualizes total sales by product category using a donut layout. It loads sales data from a remote CSV file via `d3.csv`, aggregates values with `d3.rollup`, and computes arc angles using `d3.pie`. Each slice is rendered as an SVG `path` with `d3.arc`, colored by `d3.scaleOrdinal` with `d3.schemeSet2`, and labeled at the arc centroid. A manual legend maps product names to their corresponding colors. The visualization demonstrates a standard D3 v5 pie chart workflow with external data loading and SVG rendering.