#go_top {
    width: 42px;
    height: 42px;
    position: fixed;
    background-color: #45b02e;
    bottom: 30px;
    right: 15px;
    display: none;
}
#go_top:before {
    content: "";
    position: Absolute;
    width: 0;
    height: 0;
    border: 11px solid transparent;
    border-bottom: 11px solid white;
    left: 10px;
    top: -4px;
}
#go_top:after {
    content: "";
    position: Absolute;
    width: 10px;
    height: 17px;
    background-color: white;
    left: 16px;
    top: 17px;
}