Why is my display fuzzy and blurry but the mouse and keyboard still work?

Why does my Surface Pro 4's screen suddenly look fuzzy or almost blurry, as if there's some weird motion artifact on it, while the mouse and keyboard still respond normally? It doesn't show up in screenshots, only when I look at the actual display, which is why I had to photograph the screen instead. I'm on Windows 10 Pro, build 19045.6466, and I mostly use Chrome for Netflix, NFL games, and other sports.

I admit I used a mirror site today to watch a game, and it was full of pop-up ads—the most common one kept pushing Opera. That's when I first noticed the fuzzy, blurry, aberrant motion. I already rebooted and cleared temp files, but it's still there. Could this be a driver problem, a display scaling issue, or something that got installed from that site? And how do I tell whether it's a hardware fault on the Surface or something software-related that I can fix?