.go-top {
    position: fixed;
    bottom: 0.7em;
    right: 0em;
    text-decoration: none;
    /* color: white; */
   /* background-color: rgba(0, 0, 0, 0.25); */
   /* font-size: 12px; */
     padding-top: 17px;
     padding-bottom: 17px;
     padding-left: 17px;
     padding-right: 17px;
    display: none;
    margin: 0;
    background-image:url("button-back_to_top4.png");
    opacity: 0.7;
}

.go-top:hover {
    background-image:url("button-back_to_top_hover.png");
}