Entire Site Adjusted In Size & Layout

Drew...I was reviewing a design sent to me and it had a tiny button at the top that said 133%.  The person told me to click on it to make it 100% and when I did, the entire Roundcube screen and layout changed.  The font of everything is very small and rather than having all new e-mails appear on the screen, it's now only 1/3 of the top of the screen with a huge white box with RC+ below it.  Can you please help me so I can return everything to its previous view, size, and layout?  Thanks.