CodePen

HTML

            
              	


<div id="thewindow">
  <div id="background_blackboards">


</div><!-- END div id blackboard   --> 
 
</div><!-- END div id window  --> 
 

            
          
!

↑ Insert the most common viewport meta tag

CSS

            
              
#thewindow{
            width: 960px;
            margin: 0 auto;			
	}
	
	
#background_blackboards{
	margin-top:65px;
	width:950px;
	height:460px;
	background: url("http://www.babysitter-agency.com/images/blackboard.png");
}


            
          
!
? ?
? ?
Must be a valid URL.
+ add another resource
via CSS Lint

JS

            
              
            
          
!
Must be a valid URL.
+ add another resource
via JS Hint
Loading ..................