Move some styles to the Apex theme

Change-Id: Ifb3fed191cb2f98e386fdff8cb3cdad4c74a301a
Add basic styling for Agora theme

It will be first used in mobile link inspector and contains only the
styles needed for link inspector (for now).

Change-Id: Ife4086319c82f49de8fc7d5bcd6f3563c161fff9
Merge "Move some styles to the Apex theme"
Merge "Add basic styling for Agora theme"