styling a lit element

In Vaadin 14 you could do something like this:
Did this change since vaadin 23? IntelliJ says Incompatible override for member from ReactiveElement on the method

It works, so I guess I can ignore this hint by intellij?

It’s basically the same in Vaadin 23 Styling | Templates | Creating UI | Vaadin Docs

( only the imports are different since it’s lit 2)

Okay thanks. And what about the error IntelliJ gives me? Can I disable that, cause all files are marked as red. Its the “ECMAScript specification is not followed” inspection