This example visualizes the top 10 most populous countries in 2020 as a horizontal bar chart using React and D3. The data, loaded via `d3.csv` from a UN population dataset, is rendered as SVG rectangles whose widths encode population values. A `scaleBand` positions countries along the y-axis, while a `scaleLinear` maps population to pixel widths. The chart demonstrates the margin convention by offsetting the render group with `transform` and calculating `innerHeight` and `innerWidth` from fixed margins.