A line chart tracks global cumulative COVID-19 deaths over time, with one gray line per country. Hovering over any point highlights that country's entire line in black. The chart uses a log-scaled y-axis and renders as SVG. A Voronoi overlay, built with `d3.Delaunay`, partitions the chart area into mouse-sensitive regions for each data point, enabling easy hover detection without precise cursor targeting. Data comes from the COVID-19 Data Repository by the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University, loaded via `d3.csv`.