[Koha] CSS for OPAC login form

[Contact Orielstar]

Hi Folks,

I am trying to put a border around the login form on the OPAC home page 
but when I set my display to 768px wide I see some very strange 
behaviour - well, it seems strange to me.

The form element is <form id="auth", and within this form is a fieldset 
containing the input boxes for username and password. Here's what I am 
struggling with... the fieldset.brief element is wider than the form 
element, even though it's inside it. I can't see why as the width is set 
to auto, but if I try and put a border around the form then the input 
boxes actually poke through the side. If I put a border around the 
fieldset.brief element then it hangs over the side of the page.

I think I've missed something fundamental and it's cooking my head... 
can any of you clever css experts out there explain to me what I have 
missed, and how I can get a box around the login form that looks fine at 
all screen resolutions?

I thank you very much for your help in advance.

Regards,

Dave Jury.