This example demonstrates the margin convention for bar charts by displaying the top 10 countries by population in 2020. The chart uses React to render SVG rectangles, with D3’s `scaleBand` for the y-axis countries and `scaleLinear` for the x-axis population values. Data is loaded via `d3.csv` from a UN population dataset. A `<g>` element applies the margin translation, showing how inner dimensions are computed from the SVG width, height, and margin object.