This example visualizes Bitcoin trading activity using a line chart that plots both trading volume and opening price over time. The visualization is built with the Vega-Lite API, which constructs a specification rendered through Vega and Vega-Lite libraries, with the final output displayed as an SVG. Data is loaded asynchronously from a CSV file using d3.csv, and the chart dynamically sizes to fit the browser window. Custom axis styling and tooltips, powered by vega-tooltip, enhance readability of the time-series data.