Custom header not working

I’m currently using a Twenty Thirteen child theme and I wanted to overlay four hyperlinked examples of our sponsors on the header as a kind of bang for their buck.

I placed the properly sized sponsor pngs in my twenty thirteen child theme’s image folder and attempted to load the code I tested in dream weaver. The website I’m doing this on is https://www.highcountryrugby.com

What follows is the php and css code that should’ve taken but didn’t. If anyone can point out where I went wrong I’d be grateful.

CSS:

#sponsor1{
	height: 64px;
	width: 100px;
	background: url(../images/sp1.png) no-repeat;
	position: absolute;
	top: 160px;
	left: 480px;
	z-index:500;
}

#sponsor2{
	height: 64px;
	width: 100px;
	background: url(../images/sp2.png) no-repeat;
	position: absolute;
	top: 160px;
	left: 595px;
	z-index:500;
}

#sponsor3{
	height: 64px;
	width: 55px;
	background: url(../images/sp3.png) no-repeat;
	position: absolute;
	top: 160px;
	left: 710px;
	z-index:500;
}

#sponsor4{
	height: 64px;
	width:169px;
	background: url(../images/sp4.png) no-repeat;
	position: absolute;
	top: 160px;
	left: 775px;
	z-index:500;
}

PHP

<a href="www.highcountryoutfitters.com"><div id="sponsor1"></div></a>
<a href="http:\\www.hcrivers.com"><div id="sponsor2"></div></a>
<a href="www.brewhousecafe.com"><div id="sponsor3"></div></a>
<a href="www.carlsberg.com"><div id="sponsor4"></div></a>