This example visualizes the top 10 most populous countries in 2020 using a horizontal bar chart rendered as SVG. It loads medal data from a CSV via `d3.csv`, slices the first 10 rows, and uses `scaleBand` for the y-axis and `scaleLinear` for the x-axis to map country names and population values. The React app manages data with `useState` and `useEffect`, while custom tick labels and grid lines are generated manually with D3 scales instead of using `axisLeft` or `axisBottom`. Bars are drawn as `<rect>` elements inside a translated `<g>` group.