* {
	padding:0;
	margin:0;
}


#div_demo {
	width:100%;
	height:640px;
	position: relative;
}

#div_demo span {
	display: block;
	position: relative;
	margin:0 auto;
	color:#fff;
	font-size:3em;
	padding-top:40px;
	font-weight: bold;
	text-align: center;
	width:250px;
	
}

@media only screen and (max-width:1000px) {
	
	#div_demo {
    height: 400px;
    position: relative;
    width: 100%;
}

}

@media only screen and (max-width:650px) {
	
	#div_demo {
    height: 300px;
    position: relative;
    width: 100%;
}

}






@media only screen and (max-width:400px) {
	
	#div_demo {
    height: auto;
    position: relative;
    width: 100%;
}

}