This example demonstrates how to load and parse an external CSV file using D3.js, rendering the resulting data as an interactive bar chart. The visualization uses `d3.csv()` to fetch the dataset and `d3.rollup()` to aggregate values by category. Each bar is drawn as an SVG rect, with its height and position calculated using D3's linear scale for the y-axis and band scale for the x-axis. The chart includes axes with tick labels, and a hover effect highlights individual bars while displaying the corresponding data value in a tooltip. The design uses a clean white background with colored bars, making the data easy to compare at a glance. This example demonstrates D3's data loading, parsing, and binding workflow.