focus doesn't look sharp through viewfinder

The images through the viewfinder have suddenly become fuzzy although the pictures are actually focused. This is happening no matter which shooting mode I am in. Has anyone else had this problem? I consider myself still a novice and certainly don't know everything about this new camera. I've had it about 6 months but am just now experiencing this problem. Could I have accidentally reset something?

have you tried messing with the tiny black slider underneath the viewfinder?

I didn't find anything under the viewfinder but I did find the diopter control and adjusted it and that seemed to fix the problem. Thanks!

Nothing like a happy ending

A classic case of Move the Diopter setting while he's not looking. I just wish I had a diopter adjustment for my eyes.

uffff... such a relief... I was already thinking my viewfinder was broke after falling (into my feed luckily). The Diopter adjustment did the trick. Thank you guys!