This interactive visualization combines a scatter plot and a categorical color legend to show GDP variation across years for the USA and Germany. Users can click a country in the legend to filter the data, highlighting selected points while dimming others. The project uses D3 v5 with `d3.scaleOrdinal` for color assignment, `d3.scaleLinear` for axes, and `d3.axisBottom`/`d3.axisLeft` for tick marks, rendering as SVG from a CSV dataset.