#rtscrolltop{ 
height: 40px; 
width: 40px; 
position:fixed;
bottom:50px;
right:50px;
text-indent:-9999px;
display:none;
background: url("icon_top.png"); 
-webkit-transition-duration: 0.1s; 
-moz-transition-duration: 0.1s; 
transition-duration: 0.1s; 
}