This line chart displays temperature readings over time, with each point marked by a circle and connected by a smooth, curved path. Built with React and D3 v5, it uses `scaleTime` and `scaleLinear` for the axes, `line().curve(curveNatural)` for the path, and native SVG `<circle>` elements with `<title>` tooltips. Data comes from a CSV of weekly San Francisco temperatures, loaded via `d3.csv`, with reusable axis and mark components rendering the visualization.