Customizing Axes
This bar chart displays the population of the ten most populous countries, with populations formatted in billions using a custom tick formatter. The visualization uses `d3.scaleBand` for the categorical y-axis and `d3.scaleLinear` for the numeric x-axis. It customizes both axes by removing domain lines, adding a horizontal grid via `tickSize(-innerHeight)`, and appending axis labels. The chart is rendered with SVG elements and loads data from a CSV file using `d3.csv`.