stylesheet not working on Firefox

[biojohn]

I recently integrated several Zencart downloads to my site (http://www.bioland-sci.com). Now the stylesheet.css doesn't work for Firefox (FF) but still OK for IE. For example, after I modified color code of #mainwrapper, #NavCatTabs, the display on IE changed correspondently but nothing happened on FF. The ultimate purpose is that I want to make the header layout on FF the same as on IE. I appreciate if someone could help me do it.

[usernamenone]

It is always a good idea to validate your stylesheets and while I checked it for errors I found several that can cause browser issues.

http://jigsaw.w3.org/css-validator/v...usermedium=all

[biojohn]

Thanks for the reply. I'll try it.

[biojohn]

The CSS validation program is really helpful. I corrected all the stylesheet.css errors. But I still have two errors of the same problem, I don't know how to correct them:
1. /CUSTOM/css/stylesheet_categories_menu.css
Property behavior doesn't exist : url(./csshover.htc)
2./CUSTOM/css/stylesheet_header_menu.css
body Property behavior doesn't exist : url(includes/csshover.htc)