Task 1
A horizontal bar chart displays the top 30 countries by population in 2020. React renders the SVG, while D3 v5's `scaleBand` and `scaleLinear` position bars and map values to pixel widths. The chart includes labeled axes with a custom tick formatter converting values to billions. Hovering over each `rect` reveals the population via a native SVG `<title>` tooltip. Data is loaded from a CSV file using D3's `csv` parser.