.boxgroesse {
    width: 700px;
    height: 350px;
	opacity: 0.7;
	border-radius: 15px;
	

}
 
#box1 {
    background-color: white;
	position: absolute;
    top: 10%;
    left: 5%;
	
    
	}
 


html{
	/* This image will be displayed fullscreen */
	background:url('background.jpg') no-repeat center center;

	/* Ensure the html element always takes up the full height of the browser window */
	min-height:100%;

	/* The Magic */
	background-size:cover;
}

body{
	/* Workaround for some mobile browsers */
	min-height:100%;
}