This horizontal bar chart displays the top 30 countries by 2020 population, using green bars to compare values across a blue-ticked axis. The visualization loads CSV data from a GitHub gist, parses the population column, and renders an SVG using D3 v7's `scaleLinear`, `scaleBand`, and `d3.axisBottom`/`axisLeft`. Custom ES6 modules (`Marks.js`, `AxisBottom.js`, `AxisLeft.js`) encapsulate the bar drawing and axis formatting, with tick labels formatted in compact notation (e.g., "1.2B").