A multi-series line chart displays trends for Sales, Revenue, and Profit, plotting lines color-coded by metric. Built with D3.js v7, the code uses `d3.scaleLinear` for axes, `d3.line` for path generation, and `d3.axisBottom`/`d3.axisLeft` for gridlines and ticks. Data is loaded from a CSV file and rendered as SVG, with a legend displaying the color mapping.