Looking for responsive embed Videos? Hier is the CSS only trick. You only have to remove width/height in the <iframe> tag. Thanks to www.andmag.se/2011/11/responsive-embeds

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.embed {
	position: relative;
	overflow: hidden;
	height: 0;
	padding-bottom: 56.25%; /* 16/9 ratio */
	padding-top: 30px; /* IE6 workaround*/
	
	iframe {
	    position: absolute;
	    top: 0;
	    left: 0;
	    width: 100%;
	    height: 100%;
	}
}