This pie chart visualizes the distribution of employees across departments from an HR dataset loaded via D3's `d3.csv` fetch. The D3 v7 code uses `d3.pie()` and `d3.arc()` to compute and render the chart’s arcs, with a sequential color scale (`d3.scaleOrdinal` with `d3.schemeCategory10`) distinguishing departments. Each slice includes a tooltip showing the department name and count, while a legend on the left uses SVG rectangles and text labels to identify colors. The visualization is rendered entirely as SVG elements.