-moz-transition color on list item
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sorry a bit of a silly question, I'm new to html and css, but I can not work out what is happening here. The page I'm working on is: http://advancebuildingsnew.server105.com

The navigation has a transition for all on hover:

    #mainnav ul li a{
    	text-decoration:none;
    	font-size:13px;
    	color:#333333;
    	transition: all 0.5s;
    	-moz-transition: all 0.5s;	
    	-webkit-transition: all 0.5s; /* Safari and Chrome */
    	-o-transition: all 0.5s; /* Opera */
    }

This works fine on Chrome, however in Firefox affects only the subnavigation...I was wondering if anyone has any ideas as to where I've gone wrong.

Thank you very much!