I see what you mean but, it looks OK in either browser, something to consider before knocking one's self out trying to get them to look identical in both browsers. I had some ideas but they all flew out the window when I downloaded your frameset page and displayed it in FF without any content pages, the borders were there! I tried a bunch of other things:
- remove !doctype
- remove margins
- put style on content pages
The last showed some promise but essentially only changed the problem. The rest did nothing useful.
I've got it. You need this on the style for the content page's body (left frame) in place of the background or background-color statement (whichever you used):
and add the 'background: #e0ffe7;' to the frame tag's style as well, while losing the margin attributes there. Do this across all the pages and frame tags using the appropriate colors and you will have it.
margin: 10px!important; margin: 5px; background:none!important; background: #e0ffe7;