United Nations Bar Chart - Refactored
A horizontal bar chart displays the top 10 countries by 2020 population, using United Nations data loaded via D3's `csv` and rendered as SVG through React components. Population values from the CSV are parsed and converted to counts, with a linear scale mapping them to bar widths and a band scale for country positions. The visualization includes formatted axes with tick labels, a population axis label, and tooltips showing abbreviated values via D3's `format`. Custom React components (`AxisBottom`, `AxisLeft`, `Marks`) structure the chart, while D3 v7 handles scales, data loading, and formatting.