This line chart shows smartphone sales in millions from 2012 to 2021, with year on the x-axis and sales on the y-axis. It uses React and D3 v5, loading data from a GitHub-hosted CSV via d3.csv. The SVG rendering uses d3.scaleTime, d3.scaleLinear, d3.axisBottom, d3.axisLeft, and d3.line to draw the path, with grid lines and axis labels styled via CSS.