CSS Selector for Lumo Variant

Hi, I wanted to ask if there’s a CSS Selector for the currently used Lumo Variant, and if yes how is it called and used?

So I take it you’re referring to the DARK variant of Lumo? If so, you can target that with [theme~="dark"] {...}

so to style e.g. vaadin-buttons in the dark theme, you could do
[theme~="dark"] vaadin-button {...} in your styles.css