I am relatively new to emacs and am liking it... so much so that I'd like to customize the look and feel.
I'm aware the Custom Theme is the new way and is different from Color Theme.
The one thing that gives me pause is that Custom Theme cannot be undone. That freaks me out.
As I understand it, this means that if/when I uninstall Custom Theme 1 and install a new Custom Theme 2, the first one might leave remnants behind that still linger when I use Theme 2. Some of those remnants could conflict and give strange appearances (strange meaning different what Theme 2 intended).
How pervasive is this problem of Custom Themes leaving remnants behind? In practice, are there "good-behaving" Custom Themes that clean up after themselves when uninstalled? If things go bad, is the only option to go nuclear (i.e., re-install emacs, saving my init file)?