Hello @ll,
I have modify AFP Masthead (Switched Welcome Message Box from menu bar to masthead)
and followed CSS problem now, see Screenshot.
The Welcome Message Box is to high (TOP:5px). Correct will be TOP:10px.
I looking foward to change the Welcome Message CSS properties in Theme Editor but there
i missing the property for TOP. 
Please can somebody help me?
It is possible to add new CSS properties for my Customer Theme?
How can I change this?
Regards
Armin