This example shows the population distribution of countries as a pie chart, with each slice labeled by country in a legend beside the chart. The visualization uses D3 v7 to load CSV data from a GitHub gist, compute pie angles with `d3.pie`, and render slices using `d3.arc` into SVG paths. A tooltip, implemented with HTML overlays, displays the country name and population on hover. Colors are assigned via `d3.scaleOrdinal` with `d3.schemeCategory10`.