Mapbox Studio Classic, which used classic styles, is no longer in active development. To learn more about our newer mapping tools see Mapbox Studio styles.
In the legacy Mapbox Studio Classic product, a classic style contained CartoCSS stylesheets, thin metadata (name, description, attribution, etc.), and a reference to a source.
Creating a new map? Mapbox Studio is the modern alternative to Mapbox Studio Classic. If you're creating a new map today, you should use Mapbox Studio instead of Mapbox Studio Classic.