Related: please never use red to give me feedback on what I typed into your form. It’s not dangerous if I have skipped filling out a field. And it’s awkward because it’s not clear at what point you should “warn” me about it; after all, the form usually starts out empty, and that’s not considered an error.

By focusing on what I completed you give a much more helpful vibe, and you can reserve red for destructive actions, like permanently deleting something.