This scatter plot visualizes the relationship between vehicle weight, horsepower, and miles per gallon using the auto-mpg dataset. Semicircle marks represent individual car models, with color encoding weight and size encoding fuel efficiency, while tooltips display model names. Built with the Vega-Lite API, it registers Vega, Vega-Lite, and Vega-Tooltip to render an interactive SVG visualization. The chart loads CSV data through d3.csv, applies custom axis and label styling from a configuration object, and automatically fits to the browser window dimensions.