This line chart displays weekly temperature readings from San Francisco, sourced from the UCI Machine Learning Repository via a raw CSV file. The visualization uses vega-lite-api to generate a single semi-transparent line, with the x-axis mapped to timestamp and the y-axis to temperature, both with scales that omit zero. The code calls vl.markLine() and vl.encode() to build the chart, while d3.csv fetches the data. Custom axis styling and a 30px title font improve readability.