#scrollToTopArrow {
    position: fixed;
    bottom: 20px;
    right: 20px;
    width: 40px;
    height: 40px;
    background-color: rgba(0,0,0,.4);
    color: #fff;
    text-align: center;
    line-height: 40px;
    font-size: 24px;
    cursor: pointer;
    z-index: 1000;
    border-radius: 2px;
    display: flex;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity .2s ease-in-out;
}
#scrollToTopArrow.active{
    visibility: visible;
    opacity: 1;
}
#scrollToTopArrow:hover {
    background-color: rgba(0,0,0,.8);
}

#scrollToTopArrow img{
    width: 28px;
}