This visualization displays monthly car sales data as a combined line and area chart, using a smoothed curve to emphasize trends. The chart plots sales volume over time, with the area beneath the curve filled in orange to highlight the magnitude of sales. The implementation uses D3 v5 with `d3.line()` and `d3.area()` generators, both configured with a `curveBasis` interpolation. Scales are created with `d3.scaleTime()` and `d3.scaleLinear()`, while axes are rendered using `d3.axisBottom()` and `d3.axisLeft()`. Data is loaded as CSV from a GitHub gist and parsed with `d3.timeParse()`.