.header {
    z-index: 99999;
    height: 100px; 
    height: initial;
}

@media (max-width: 800px)
{
	.header {
	    height: 70px;
	    height: initial;
	}
}

@media (max-width: 520px)
{
	.header {
	    height: 50px;
	    height: initial;
	}
}