A line chart displays temperature variation across a week in San Francisco, using time on the x-axis and temperature on the y-axis. The visualization renders a smooth, curved line using d3.line with curveBasis, overlaid on axis grids generated by d3.axisBottom and d3.axisLeft. Data is loaded as CSV from a remote GitHub repository, parsed with d3.csv, and mapped using d3.scaleTime and d3.scaleLinear. The SVG output is styled with custom CSS classes for axes, labels, and the line path.