Blank pages in Safari and in Word

I have an intermittent display bug. Here's how it manifested today: I was working in Word and all the text in the document went invisible. I could click in parts of the document and the new cursor location would be reflected in the comments sidebar. In other words, the text was still there, I just couldn't see it. I was thinking it was a Microsoft issue and went to Safari to google it. Only when the page loaded, it was all black. And then when I clicked on other working tabs in Safari, parts of those pages started turning black, too. I'm using Sonoma 14.6.1. Any ideas on what's causing this?