移到超链接时陷下效果

a:hover {
 
  
 font-family: "微软雅黑", "宋体";
 
  
 font-size: 12px;
 
  
 font-weight: normal;
 
  
 color: #006704;
 
  
 text-decoration: none;
 
position : relative;
  top : 1px;
  left : 1px;
 
 }