.lns_backtop_btn {
    display: none;
    width: 32px;
    height: 32px;
    position: fixed;
    right: 16px;
    bottom: 100px;
    justify-content: center;
    align-items: center;
    z-index: 10;
    opacity: 0.5;
    background: rgba(255, 255, 255, 0.519);
    box-shadow: 0 4px 16px rgba(160, 160, 160, 0.186);
    border-radius: 100%;
    -webkit-border-radius: 100%;
    -moz-border-radius: 100%;
    -ms-border-radius: 100%;
    -o-border-radius: 100%;
    transition: .4s;
    -webkit-transition: .4s;
    -moz-transition: .4s;
    -ms-transition: .4s;
    -o-transition: .4s;
}

.lns_backtop_btn:hover {
    opacity: 1;
}

.lns_backtop_btn svg {
    fill: #000;
    width: 20px;
    height: 20px;
}