The thing I currently miss most about our old CSS theme is this:

When viewing messages in a flat mode thread, I didn't need to decipher the visual clutter and look for a tiny icon to determine whether a post is "new" or not. Instead, there was a subtle but clear color change in the post header for new posts. Much easier on the eyes.

I hope for a working version of our old style sheet. I wish I had the time to actually help work on it. Sorry.

On the good side, I like how wide posts don't mess up the width of all the other posts in the thread.