Background position not working in FireFox

PLEASE DELETE POST - I found the problem to be relating the correct CSS page back to my HTML.

I have a sprite I’m trying to get to work and when I view Firebug it’s completely ignoring the fact that I have a background-position: declaration in my CSS.

(I’m having issues with the “#as span” and the “#iso span”

I did some reading and all I could find was FireFox has issues with background-position-x & -y. This is not my case.

I also tried typing in background-position right into Firebug and it came up crossed out with an “Invalid Property Value”

I’m at a loss here…

	<ul id="certsHeader">
		<li id="ts"><a href="documents/certifications/ISO_TS16949.pdf" target="_blank"><span></span>TS16949 (ISO9001)</a></li>
		<li id="as"><a href="documents/certifications/AS9100.pdf" target="_blank"><span></span>AS9100</a></li>
		<li id="iso"><a href="documents/certifications/ISO14001.pdf" target="_blank"><span></span>ISO14001</a></li>	
	</ul>
	#certsHeader{
		float: left;
		font-size: 11pt;
		margin: 35px 0 0 125px;
		color: #696969;
		font-weight: 600;
		font-style: italic;
		position: relative;
	}

		#certsHeader li{
			display: inline-block;
			margin-left: 75px;
			
		}

		#certsHeader li a, #certsHeader li a:visited{color: #696969;}
		
		#certsHeader li a:hover{color: blue;}

		#ts span{
			background-image: url('images/certIcons.png');
			
			position: absolute;
			top: 0;
			left: 40px;
			
			height: 18px;
			width: 25px;
			
		}
		
		#as span{
			background-image: url('images/certIcons.png');
			background-position: -25px 0px;
			
			height: 18px;
			width: 16px;
		
			position: absolute;
			top: 0;
			left: 270px;

		}
		
		#iso span{
			background-position: -41px 0;
			
			position: absolute;
			top: 0;
			left: 400px;
			
			height: 18px;
			width: 16px;
		}

Hi,

Do you have a link to the page as that code seems to be working? If the site’s not live then perhaps attach the sprite so we can see what we are dealing with.