#back-top {
    position: fixed;
    bottom: 10px;
    right: 10px;
    z-index: 3;
    display: none;
}
 
#back-top a {
    width: 50px;
    height: 50px;
    display: block;
	transition: background-color .15s;
    -moz-transition: background-color .15s;
    -webkit-transition: background-color .15s;
    -o-transition: background-color .15s;
    -ms-transition: background-color .15s;
}