responsive theme

Hello, I have set a banner instead of title&description. This banners is made out of a few logos. Each logo must display it's title at mouseover and open a new tab with it's address upon click. I've tried to use this code:

<a href="http://www.europa.eu" title="European Union">

            <div style="width:100px; height:100px; position:absolute; background:#555; top:120px; left: 145px;">

            </div>

            </a>

, but the problems is that the position 120 and 145 will remain the same. So if I use a different resolution on PC, on a phone or tablet, the square I made will remain fixed, and will not move with the new resolution, so it's out of place. Any idea how can I make this work? Thank you so much! Regards, Andrei