我自己做了一个很简单的布局,其中有几处问题。有可运行代码,请指教!!
我是初学布局的新手,今天做了一个布局,可是为什么中间的span部分都变成隐藏的了?   
 这三个span应该是中间平行的三列。可是现在都显示不出来 
                       <span   class= "c3 "   id= "searchspan ">  </span>  
                       <span   class= "c4 "   id= "centerspan ">  </span>  
                       <span   class= "c5 "   id= "loginspan ">  </span>      
 求解!     
 代码如下:   
  <!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> xxxx </title>  
  <style   type= "text/css ">  
 *   { 
 	margin:   0;   padding:0 
 } 
 body   { 
 	margin-top:   10px; 
 	margin-right:   auto; 
 	margin-bottom:   10px; 
 	margin-left:   auto; 
 	text-align:   center; 
 	height:   auto; 
 	width:   auto; 
 	background-color:   #666666; 
 	font-size:   12px; 
 	color:   #000000; 
 } 
 .blank2{   height:2px;   clear:both;   font-size:1px;overflow:hidden;} 
 .blank3{   height:3px;   clear:both;   font-size:1px;overflow:hidden;} 
 .blank5{height:6px;   font-size:1px;   clear:both;overflow:hidden;} 
 .blank9{   height:9px;   font-size:1px;   clear:both;overflow:hidden;} 
 .logobar   { 
 	margin:0   auto; 
 	width:   760px; 
 	height:   80px; 
 } 
 .navigate   { 
 	margin:0   auto;    
 	width:760px;    
 	height:40px; 
 } 
 .adbar   { 
 	margin:0   auto; 
 	width:760px; 
 	height:70px; 
 } 
 .mainbody   { 
 	margin:0   auto; 
 	width:760px; 
 	height:600px; 
 } 
 #searchspan   { 
 	width:160px; 
 	height:200px; 
 } 
 #centerspan   { 
 	margin:1px   1px 
 	width:500px; 
 	height:200px; 
 } 
 #loginspan   { 
 	width:   190px; 
 	height:   200px; 
 } 
 #usershow   { 
 	width:   100%; 
 	height:   300px; 
 } 
 #userlist   { 
 	width:   380%; 
 	height:   100px; 
 } 
 #articlelist   { 
 	margin:   2px; 
 	width:   380px; 
 	height:   100px; 
 } 
 .footer   { 
 	margin:0   auto; 
 	width:   760px; 
 	height:   100px; 
 } 
 .c0   { 
 	background:red; 
 } 
 .c1   { 
 	background:orange; 
 } 
 .c2   { 
 	background:#F0B6A8; 
 } 
 .c3   { 
 	background:#F4F6E8; 
 } 
 .c4   { 
 	background:#B8A8F1; 
 } 
 .c5   { 
 	background:#D6E296; 
 } 
 .c6   { 
 	background:#C3D4CE; 
 } 
  </style>  
  </head>  
  <body> 	 
  <div   class= "logobar   c1 ">  
  </div>  
  <div   class= "blank3   c0 ">  
  </div>  
  <div   class= "navigate   c2 ">  
  </div>  
  <div   class= "blank3   c0 ">  
  </div>