.platzhalter_bg_medium{
z-index:16;
position:relative;
float:left;
width: 610px;
height: 500px;
background: rgba(255, 255, 255, 0.8); 
margin:5px 5px 5px 5px;
}
.platzhalter_medium{
z-index:17;
position:relative;
float:left;
width: 610px;
height: 500px;
margin:0px 0px 0px 0px;
}

@media only screen and (max-width: 1000px) and (orientation : landscape)
{

}
@media only screen and (max-width: 480px)
{
	.platzhalter_bg_medium
	{
		width: 300px;
	}
	.platzhalter_medium
	{
		width: 300px;
	}
}