I just made the mistake of allowing the upgrade to 2023.3 Build #IU-233.11799.241 to proceed just now.
I find all my colors are gone and I'm left with an unwanted dark view. I know, from having looked from my similarly misfortunate PyCharm upgrade a few weeks back (I'm not currently working in Python, so I didn't take time out to complain), there there are no reliable, easily appliable light themes anymore to get me back to what I want.
What's the shortest way back to sanity? I have actual work to do.