Where is the css and are my edits going there in an Upfront theme?

Ooooookay. So I was experimenting with Scribe, and I added a floating region. Now I can't take it out! It only shows when my mouse is over other regions, and disappears when I try to click on it to take it out. I can find what div it is when I inspect the page, but where do I find it to delete? I see that the stylesheet is incredibly short.

Also, I grouped some elements together in an attempt to keep them in place better for tablet and mobile sizes. However now it's all a jumbled mess and won't let me ungroup the bits so I can remove those as well. Again, wanted to just go delete in the stylesheet, but that's not the right answer. Where does the code go when you edit from the front end?