This line chart shows book sales per year, with a green line tracing the trend over time. The chart includes labeled axes, gridlines, and a title, using D3 v5’s `scaleTime`, `scaleLinear`, `line`, `axisBottom`, and `axisLeft` APIs. Data is loaded from a CSV file via `d3.csv`, with year values parsed as dates. The SVG is rendered with margins and axis labels, and gridlines are created by setting negative tick sizes on the axes.