This pie chart visualizes the revenue share of professional sports clubs, grouped by sport, using data from a CSV file loaded via `d3.csv`. Each slice represents the total revenue in USD millions for a sport, with labels showing the sport name and percentage of total revenue, while a legend displays each sport’s combined earnings. The chart is rendered as an SVG using D3 v7, with `d3.pie` and `d3.arc` generators to compute and draw the slices, and `d3.scaleOrdinal` with `d3.schemeTableau10` for color encoding. Data aggregation is performed using `d3.rollup` and `d3.sum`.