#back-top {
position: fixed;
bottom: 90px;
right: 10px;
z-index: 9999;
display:none;
}
#back-top a {
width: 51px;
display: block;
text-align: center;
font-size: 11px;
line-height: 18px;
font-family: "Trebuchet MS", Arial, Helvetica, sans-serif;
text-transform: none;
text-decoration: none;
color: #6c6c6c;
-webkit-transition: 0.2s;
-moz-transition: 0.2s;
transition: 0.2s;
}
#back-top span {
width: 51px;
height: 51px;
display: block;
margin-bottom: 7px;
background: url(jquery.back-top.png) no-repeat center center;
opacity: 1;
filter: alpha(opacity=100);
-webkit-transition: 0.2s;
-moz-transition: 0.2s;
transition: 0.2s;
}