This example visualizes bank customer data as an interactive bar chart with five series of ten values each, rendered as SVG rectangles. Users can toggle between grouped and stacked layouts using custom radio buttons built with D3 selections. The chart uses `d3.stack`, `d3.scaleBand`, and `d3.scaleLinear` for layout, with hover tooltips displaying precise values via a D3-managed HTML div. Data comes from a CSV file loaded asynchronously through a custom `useData` React hook, and transitions animate between layout states.