Trinity Bars Hide during out of combat OR button press

[Hardhead]

Just recently coming back to WoW. With Discord Bars gone, I decided to give Trinity a try. It has pretty much everything I want, with one exception. I like a super-clean interface. With DAB, I used to run with my bars invisible unless I entered combat or was holding down the Alt key.

With Trinity, it seems I can do one or the other, though I don't completely understand the header system. Can someone help me out with this?