Chat scale in 4k

Hi all. Today i was playing the game and i was pretty much pissed. So I smashed the keyboard and got the red boarder around the sceen so i could not move the camera. All i did is reset interface and it did not helped. After the reset i got really small chatbox. And i was unable to change it back to normal. I play in 4k resolution and this is annyoin because i can't really read anythin in chat even if i scale it up to 100. Any solution? Thank you. The bad thing i don't remeber how i made it bigger for some reason. Please help me :)