#toTop {
    display: none;
    text-decoration: none;
    position: fixed;
    bottom: 10px;
    right: 10px;
    overflow: hidden;
    width: 48px;
    height: 48px;
    border: none;
    text-indent: 100%;
    background: url(../img/back-top.png) no-repeat 14px 16px #ddd;
    border-radius: 100px;
    -webkit-border-radius: 100px;
    -moz-border-radius: 100px;
    -o-border-radius: 100px;
}
#toTop:hover{
    background: url(../img/back-top.png) no-repeat 14px 16px #777;
}