This example visualizes the top 30 most populous countries in 2020 using a horizontal bar chart, with each bar’s length encoding population size. The chart is built with React and D3 v7, using `d3.scaleLinear` for the x-axis and `d3.scaleBand` for the y-axis categories. Population data is fetched from a CSV hosted in a GitHub gist, with a hardcoded fallback dataset in case the request fails. The visualization renders as SVG, with custom React components for the axes and marks, and includes styled hover effects and axis labels.