This stylized bar chart displays the top 10 countries by population using data from the UN Population 2019 CSV. The horizontal bars are rendered as SVG rectangles, with country names along the y-axis and population values on the x-axis, formatted using D3's `format` function to convert values into billions. The chart uses React components for the axes and marks, with D3's `scaleBand` and `scaleLinear` for positioning, and includes a tooltip on each bar showing the population value via a native SVG `<title>` element.