This stylized bar chart visualizes the top 10 countries by population in 2020, sourced from the UN Population 2019 dataset. Horizontal bars display population values, with a linear x-axis formatted to use "B" for billions and a categorical y-axis listing country names. The visualization is built with React, D3 v7 (using `scaleBand`, `scaleLinear`, and `format`), and rendered as SVG. It demonstrates proper margin handling, custom axis components (`AxisBottom`, `AxisLeft`), and a tooltip via `<title>` elements.