Thanks. Yes, I have done this up to the last part, which is where I took a screenshot of the above Body (All Pages). But I can’t edit anything. It’s just a read-only view of the CSS, as you can see above.
Edit: Actually, I figured it out, I think… I still haven’t been able to solve the problem, but the UI you explained seems to work. It’s extremely confusing. Now I have a bigger problem.