A while ago, I did something unknowingly (I happenned to some key with Ctrl pressed). First, it did like it was zooming in. Then I tried to zoom out with `Ctrl` + `-` and the next time (now) I opened it it displays just a plain white. I didn't get any options to reset to default settings. I'm using Chrome V19. 

![enter image description here](https://i.stack.imgur.com/72kAn.jpg)