.stt-top { /* One of these will hide it without using display:none =P */
   display:block;
   text-indent:-9999em;
   font-size:0;
   line-height:0;
   height:0;
   visibility:hidden;
}
.stt-gototop {
   position:fixed;
   z-index:5000;
   bottom:40px;
   right:40px;
   background:url("http://www.mantel-verpackung.de/wp-content/stt-images/dwieeb_arrow_darker.png") no-repeat top left;
   text-indent:-9999em;
   width:30px;
   height:30px;
      display:none;
   }
.stt-gototop:hover,
.stt-gototop:active,
.stt-gototop:focus {
   outline:0;
}