This example visualizes San Francisco temperatures over time for multiple cities using a multi-line chart. The visualization employs D3 v5 APIs including `scaleTime`, `scaleLinear`, `axisLeft`, and `axisBottom` to construct the axes and scales. Data is loaded from a CSV file and grouped by city using `nest`, then each line is rendered via the `line` generator with `curveBasis` smoothing. The SVG render includes gridlines, a rotated y-axis label, and a title, all styled through CSS.