This visualization displays the top 20 countries by 2010 population as a horizontal bar chart, using a React and D3 v5 setup with SVG rendering. The population data is loaded via `d3.csv` from a GitHub-hosted CSV file, and bars are sized using `scaleLinear` and positioned with `scaleBand`. Axis components are custom React functions rendering tick lines and labels, while a native SVG `<title>` element provides tooltips. Population values are formatted with `d3.format` to show abbreviated labels like “B” for billions. Axes and marks are styled with custom CSS classes.