Be careful with your attitude is what I would say. Mind your attitude sounds British.
Why not "Watch out for your attitude!"? Another example of inadequate vetting of possible answers, I think!
Yes, and to add insult to injury, it's in the drop-down menu. Not that this is always reliable as we all know, but it has exactly the same meaning, obviously. Not to mention that "mind your attitude," DL's preferred translation is just so British, after saying many times they are focusing on American English. This needs work.