WordPress composition screens missing some dynamic style elements

For the past couple weeks, I’ve noticed certain screens of my WordPress sites have lost some of their functionality. For example, the box to the right of the new post screen looks like this:

https://i.imgur.com/xKri4Nf.png (For reference, I’m accustomed to this: https://i.imgur.com/orEDtIR.png)

And the login screen itself looks like this:

View post on imgur.com

I’ve checked this on multiple browsers to make sure it isn’t a plugin blocking a script, but it does this in both Firefox and Chrome on two different computers. I’ve reinstalled WordPress on both sites, but that has not changed the problem.

Any suggestions?