.sts-top {
  display: inline-block;
  height: 50px;
  width: 50px;
  position: fixed;
  bottom: 20px;
  right: 20px;
  overflow: hidden;
  background: url(../sts-scrolltotop/pfeil.png) no-repeat center;
  visibility: hidden;
  opacity: 0;
}
.sts-top.sts-visible {
  visibility: visible;
  opacity: 1;
}