A multi-line chart tracks cumulative COVID-19 deaths over time for each country, using a logarithmic y-axis to accommodate wide numeric ranges. The visualization encodes country data from the Johns Hopkins Coronavirus Dataset as gray SVG paths, with an active line highlighted in black when a user hovers over a data point. Hover detection is implemented via a Voronoi overlay computed with `d3.Delaunay`, which assigns the nearest data point to the mouse cursor. The chart is built with React and D3 v5, using `d3.scaleTime`, `d3.scaleLog`, and `d3.line` for axes and path generation.