The jQuery example is good, but the "vanilla" example is cleaner and simpler: the class name isn't decorated with a dot, the CSS property name is not quoted, $

The jQuery example is good, but the "vanilla" example is cleaner and simpler: the class name isn't decorated with a dot, the CSS property name is not quoted, $ might be hijacked or overloaded, it is not obvious (compared to a plain assignment) that css is a setter and what arguments it takes.