This example demonstrates an interactive scatterplot of the classic auto-mpg dataset, plotting horsepower against miles per gallon, with color encoding by origin and size by weight. The visualization is built using the Vega-Lite API, a JavaScript wrapper that constructs Vega-Lite specifications programmatically. The code registers the API with vega and vega-lite, configures a custom tooltip via vega-tooltip’s Handler, and loads the CSV data using d3.csv. The plot renders directly into the document body, sized to the browser window, with stylistic adjustments for axis labels and overall readability.