CSS to li id problems

[luckid]

i have this code but don't work. someone knows why? I don't understand!!! xD The problem is... li#1 show it!CSS Code\[code\]#csscontent { position:relative; float:right; color:#000000;}#csscontent ul { list-style:none;}#csscontent ul li { float:left;}#csscontent ul li#one { display:none !important;}#csscontent ul li#two {}#csscontent ul li:after { content:" | "; padding-left:10px; padding-right:10px; color:#CCCCCC;}#csscontent ul li:last-child:after { content: "";}#csscontent a { color:#000000;}#csscontent:hover { color:#FF0000;}#csscontent a:hover { color:#FF0000;}\[/code\]This is HTML Code\[code\]<div id="csscontent"> <ul> <li id="one"><a href="http://stackoverflow.com/questions/14432944/#" onclick="setActiveStyleSheet('black', 1); return false; actualizar();">NEGRO</a></li> <li id="two"><a href="http://stackoverflow.com/questions/14432944/#" onclick="setActiveStyleSheet('white', 1); return false; actualizar();">BLANCO</a></li> </ul></div>\[/code\]