This example shows a bar chart of average sugar levels (in grams) across six fast-food restaurant chains, using data from a Kaggle fast-food nutrition dataset. It uses D3.js version 7.8.5 with `scaleBand` and `scaleLinear` for positioning, and `d3.group` and `d3.mean` to aggregate the data. Hovering over a bar turns it black and displays a tooltip with the exact average value, while a responsive layout is handled by the `observeResize` and `axes` functions from external libraries.