Username and password fields may be missaligned on login form

Username and password fields on login form may go under prompt labels (see screenshot).

In my oppinion, the cause for the issue is usage of absolute and relative units within single form. As result form becomes sensitive to user fornt selection. Out of three browsers on my host (Google Chrome, Rekonq, Mozilla Firefox) I can reproduce issue only in Firefox.

login-form.patch fixes the issue for me.