prova così....

<div id="res" style="position:relative; width:258px; height:172px; z-index:2; visibility: visible;margin-top:0;margin-left:0;">ciao</div> <div id="aves" style="position:relative; width:258px; height:172px; margin-top:-90px;margin-left:-200px; z-index:2; visibility: visible;">ciao</div>

:bubu: