This example shows smoothed daily death counts over time for the top 50 countries, using a log-scaled y-axis. Each country is rendered as a line, and hovering over any data point highlights the corresponding line and displays a tooltip with the country name, date, and total deaths. The data comes from the Johns Hopkins COVID-19 dataset. The visualization uses React with D3 v5 for scaling, line generation, and axis construction, while a Voronoi overlay built with `d3.delaunay` handles hover detection. The smoothing is applied via a Gaussian kernel blur.