RHP page now 1/3 size, anyone know how to get it back to normal?

It is only RHP, if I go to any other site like just reading email or other sites the pages are full screen but the font size is a lot smaller and more difficult to read, screen literally half the width as before but vertical is still there.
I tried a lot of button pushes to no avail.
Any help would be appreciated.

@sonhouse
System is Windows 10.

Never mind, figured it out. It's back to full size now.

usually ctrl+0 do the trick