#back-to-top {
    position: fixed;
    bottom: 70px;
    right: 40px;
    z-index: 9999;
    display: block;
    width: 81px;
    height: 81px;
    background: transparent url("images/top.png") no-repeat scroll 0 0;
    cursor: pointer;
    border: 0;
       /* transition */
	-webkit-transition: 2s;
	-moz-transition: 2s;
	transition: 2s;
}
#back-to-top:hover {
     background: transparent url("images/tophover.png") no-repeat scroll 0 0;
}
#back-to-top.show {
    opacity: 1;
}
#content {
    height: 2000px;
}