Embeded Link Border Issues

Hi guys,

I have a form that is required to be on a black background. I'm using it as an Embed link - but when I do this - Even thought I've set the border colour to black, a white border is appearing around the form and horizontal rule around the submit buttons.

Is there an easy fix to get rid of this?

Link to show what I'm talking about is below:
http://www.adlab.com.au/test/beefystest.html