This example shows a line-area chart of weekly temperature data for San Francisco, with the area fill emphasizing the variation in temperature over time. The visualization is built using the Vega-Lite API, with `vl.markArea()` defining the mark type and `.encode()` mapping the `timestamp` field to the x-axis and `temperature` to the y-axis. Data is loaded asynchronously via `d3.csv` from a GitHub Gist, and the chart is rendered with an SVG view, configured with custom axis styles and tooltips through the `vega-tooltip` handler.