a.scroll-top {
    position: fixed;
    right: 1rem;
    bottom: 1rem;
    display: none;
    width: 2.75rem;
    height: 2.75rem;
    text-align: center;
    color: #fff;
    background: rgba(90,92,105,.5);
    line-height: 46px;
}
a.scroll-top i {
  position: relative;
  top: 2px;
}