This visualization shows Olympic medal counts by country using an interactive stacked bar chart. Hovering over the color legend highlights the corresponding medal category and dims the others. The chart uses D3’s `scaleLinear`, `scaleBand`, and `stack` to create bars, with a `flatRollup` grouping data by country and medal type. A custom `colorLegend` module handles mouse interactions, adjusting opacity and stroke width. The data source is `transformedData` from an external module, rendered responsively with `observeResize`.