<meta name="viewport" content="width=device-width, initial-scale=1.0" />

#left{
    	width: 600px;
    	float: left;
    	margin-right: 10px;
    	}
    #right{
    	width: 400px;
    	float: right;
    	}	
    	
    @media only screen and (max-width: 1010px){ 
    	#left, #right{
    		width: 98%;
    		float: none;
    		margin: 10px auto;
    		}
    }