Line Chart with Multiple Lines
This line chart visualizes temperature data from San Francisco over one week, using multiple colored lines to differentiate regions. The chart encodes profit values on the x-axis and segment categories on the y-axis, with color mapping to region through an ordinal scale. Built with D3 v5, the visualization uses `scaleLinear`, `axisBottom`, `axisLeft`, `line` with `curveBasis`, and `nest` to group data by region. A custom `colorLegend` component displays the color scale, while the SVG rendering includes gridlines, axis labels, and a title.