Fork of Fork of Fork of A7: Line Chart
This multi-line chart displays average horsepower trends from 2010 onward for four car brands—Audi, BMW, Toyota, and Ford—using data from a CSV file. The visualization uses D3 v6 with an SVG rendering approach, applying `d3.rollup` to compute yearly averages per make and `d3.line` to draw the paths. It incorporates a categorical color scale via `d3.scaleOrdinal` and a legend generated by the d3-legend plugin. Axes are built with `d3.axisBottom` and `d3.axisLeft`, and missing data values are handled using the line generator’s `.defined` method.