Three Column Dashboard?

I think this thread has now diverged from the original topic – which is one that is related to CSS in WordPress core software. xiexiema, SGallay, and Fashiongeekette – it sounds like your issue is Jetpack-related, and not CSS in WordPress itself (which wouldn’t have just altered itself spontaneously).

I just tested Jetpack myself and it seems to be the issue. Here’s a relevant thread: https://www.ads-software.com/support/topic/plugin-jetpack-by-wordpresscom-problem-with-the-admin-css-jetpack?replies=5

@helenyhou Thanks, this indeed looks more like my problem. I’ll move to the other thread.