2nd Iteration Line Graph: vgsales.csv
This multi-line chart, built with D3 v6, visualizes video game sales from the `vgsales.csv` dataset for five global regions (Global, North America, Japan, EU, and Other), with one small multiple per region. Each line tracks a genre’s sales over time, colored via `d3.schemeSet3`; interacting with the legend (hover or click) highlights or toggles the corresponding series across all charts. The implementation uses `d3.flatRollup` and `d3.sum` for one-time data aggregation, and `d3.scaleLinear`, `d3.axisLeft`, and `d3.axisBottom` to build axes. Users can pan and zoom, and the updated view synchronizes across all multiples.