Default Font Size in Desk

Default Font Size in Desk

How do I set my default font size in Desk?  It takes me about 45 minutes to find the place to set it, then, when I sign out of Zoho and log back in, it's back to font 10 again.  Seems like this would be simple, but like everything with Zoho, it's buried in the settings somewhere and I can't find it.  Help!!!