This interactive donut chart visualizes COVID-19 deaths in US states using React and D3 v4. The pie chart displays state names and death counts with hover tooltips and opacity changes for emphasis. The code loads CSV data from a GitHub gist, parses it with the `csv` function, and renders SVG arcs using `d3.arc` and `d3.pie` within a React component. A legend accompanies the chart, and mouse events trigger tooltip positioning and visual feedback.