.item-1,
.item-2,
.item-3{
	display:inline-block;
	margin:10px;
	width:100px;
	height:100px;
}
.item-1{
	background-color:red;
}
.item-2{
	background-color:green;
}
.item-3{
	background-color:blue;
}
@media (min-width: 500px) and (max-width: 800px) {
	.item-1{
		opacity:0.3 !important;
	}
	.item-2{
		opacity:0.3 !important;
	}
	.item-3{
		opacity:0.3 !important;
	}
}