[CSS] Wenn man rauszoomt, verschiebt sich die Box?

*{
	box-sizing: border-box;
	-webkit-box-sizing: border-box;
	-moz-box-sizing: border-box;
	font-family: 'Open Sans', sans-serif;
	font-weight: normal;		
}


body{
	margin: 0;
	background-color: #efefef;
	font-size: 13px;
	background-image: url(images/noise.png);	
}


#Banner{	
	float: left;	
	margin-top:5px;
	height: 191px;	
	width: 940px;	
	left: 25%;
	margin-bottom: 5px;
	/*background-image: url(images/header.png);	*/
	position: relative ;
}


#content{		
	float: left;	
	margin-top:10px;
	background: #fff;		
	text-align: center;
	width: 940px;		
	left: 25%;
	box-shadow: 0px 2px 2px rgba(0, 0, 0, 0.2);
	margin-bottom: 10px;
	position: relative ;
}