求助!把CSS文件放在不同位置~效果为什么不一样
我有一个CSS文件 
 如果把CSS文件的内容放在网页内。可以正常显示,我想要的效果。但是,另存为CSS格式后,在网页内调用,就不能出来效果。 
 CSS内容 
  <style   type= "text/css ">  
 .top1{ 
 	position:absolute; 
 	top:   0px; 
 	height:20px; 
 	width:   1000px; 
 	left:0px; 
 	padding:   1px; 
 	z-index:7; 
 	filter:progid:DXImageTransform.Microsoft.Gradient( 
 	gradientType=1,startColorStr=#FFFFFF,endColorStr=#1E77D3) 
 } 
 .top2{ 
 	position:absolute; 
 	top:   20px; 
 	height:82px; 
 	width:   990px; 
 	left:0px; 
 	padding:   1px; 
 	border-bottom-style:solid; 
 	border-bottom-color:#CCCCCC; 
 	z-index:6; 
 	filter:progid:DXImageTransform.Microsoft.Gradient( 
 	gradientType=1,startColorStr=#0A6CCF,endColorStr=#FFFFFF) 
 } 
 .left{ 
 	position:absolute; 
 	top:   84px; 
 	height:450px; 
 	width:   330px; 
 	left:0px; 
 	padding:   1px; 
 	border-right-style:solid; 
 	border-right-color:#CCCCCC; 
 	z-index:3; 
 	filter:progid:DXImageTransform.Microsoft.Gradient( 
 	gradientType=0,startColorStr=#FEFFFF,endColorStr=#CCDFF4) 
 }   
 #content   { 
 position:absolute; 
 top:84px; 
 left:330px; 
 width:662px; 
 height:450px; 
 background-color:#EFEFF2; 
 border-bottom-color:#FFFFFF; 
 z-index:2; 
 } 
 #dowm   { 
 	position:absolute; 
 	height:90px; 
 	width:   990px; 
 	left:0px; 
 	padding:   1px; 
 	top:   530px; 
 	z-index:3; 
 	border-top-style:solid; 
 	border-top-color:#CCCCCC; 
 	filter:progid:DXImageTransform.Microsoft.Gradient( 
 	gradientType=1,startColorStr=#FCFEFD,endColorStr=#1E77D3) 
 } 
 #by{ 
 	position:absolute; 
 	height:20px; 
 	width:   280px; 
 	left:10px; 
 	padding:   1px; 
 	top:   580px; 
 	z-index:4; 
 	filter:progid:DXImageTransform.Microsoft.Gradient( 
 	gradientType=1,startColorStr=#FCFEFD,endColorStr=#C1DAF2) 
 } 
 #table{ 
 	position:absolute; 
 	left:150px; 
 	top:120px; 
 	height:250px; 
 	width:   200px; 
 	background-color:#EFEFF2; 
 } 
 #msg{ 
 	font-weight:700; 
 	color:#FF0033; 
 }   
  </style>  
 网页内容   
  <!DOCTYPE   html   PUBLIC    "-//W3C//DTD   XHTML   1.0   Transitional//EN "    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd ">  
  <html   xmlns= "http://www.w3.org/1999/xhtml ">  
  <head>  
  <meta   http-equiv= "Content-Type "   content= "text/html;   charset=gb2312 "   />  
  <title> 无标题文档 </title>  
  </head>  
  <body   bgcolor= "#1E77D3 ">  
  <link   rel= "stylesheet "   type= "text/css "   href= "css/login.css "   />  
  <div   class= "top1 ">  </div>  
  <div   class= "top2 ">  </div>  
  <div   class= "left ">  </div>  
  <div   id= "content ">  
  <div   id= "table ">  
  <table   height= "20 "   align= "center ">  
        <form   action= " "   method= "post ">  
              <tr>  
                    <td   colspan= "2 "> 用户名 </td>  
                    <td   colspan= "3 ">  <input