#scrolltop
{
position: fixed;
right: 10px;
bottom: 10px;
width: 38px;
height: 36px;
opacity: 0;
z-index: -1;
filter: alpha(opacity=0);
-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=0)";
-webkit-transition: opacity 400ms ease;
transition: opacity 400ms ease;
background-color: rgba(0, 0, 0, 0.2);
border-radius: 3px;
border:1px solid rgba(100,100,100,0.3);
}

#scrolltop:before
{
color:#FFF;
display: block;
width: 37px;
height: 36px;
content: "";
background-image: url("data:image/gif;base64,R0lGODlhFgAWAMIEAObm5ufn5/f39/j4+P///////////////yH5BAEKAAcALAAAAAAWABYAAANAeLrc/jBGAOQkpNoGMBbb0g0eAW7jgR3keQ3KyprvIs9uQ8A2wZAhlS+oGxJ7R8YtuTw2ic9gNDTdVC2BQJKYAAA7");
background-repeat: no-repeat;
background-position: center center;
}

#scrolltop:hover
{
background-color: rgba(0, 0, 0, 0.5);
}

#scrolltop.on
{
right: 10px;
opacity: 1;
z-index: 109;
filter: alpha(opacity=100);
-ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=100)";
}