css 居中

#index_containner{
    text-align:center;
}
.index{
	text-align:left;
	position:relative;
	margin:0 auto; 
	top:140px;
	clear:both;
	width:1260px;
	height:auto;
	margin:10px;
	border:1px solid #00CED1;
	/*overflow: auto;*/
}

  <div id="index_containner">
  	<div class="index">
         </div>
  </div>