This bar chart displays the population of the top 10 most populous U.S. counties, using data from the 2018 United Nations World Population Prospects estimate via a CSV file. The visualization focuses on customizing D3 axes: the y-axis uses `scaleBand` with tick lines removed, while the x-axis uses `scaleLinear` with a custom tick formatter that abbreviates numbers using `d3.format`. The chart also adds an axis label and title, with styling applied through CSS classes.