This interactive line chart displays the rolling seven-day average of COVID-19 cases in the United States over time. The visualization uses React and D3 v6, with the data sourced from the New York Times’ public COVID-19 repository. The chart plots dates on the x-axis and average cases on the y-axis, rendered as an SVG using custom `AxisBottom`, `AxisLeft`, and `Marks` components. Hovering over data points triggers a `Tooltip` showing the formatted value. The code leverages D3’s `scaleTime`, `scaleLinear`, and `csv` for data parsing and scaling.