/* Small faded "back to top" box shown bottom-right once the page has scrolled down */
.stt-button {
    position: fixed;
    right: 14px;
    bottom: 14px;
    width: 34px;
    height: 34px;
    border-radius: 8px;
    background: rgba(30, 30, 30, .45);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    line-height: 1;
    cursor: pointer;
    z-index: 99998;
    opacity: 0;
    pointer-events: none;
    transform: translateY(6px);
    transition: opacity .2s ease, transform .2s ease, background .15s ease;
}
.stt-button.stt-visible {
    opacity: .55;
    pointer-events: auto;
    transform: translateY(0);
}
.stt-button.stt-visible:hover {
    opacity: 1;
    background: rgba(20, 20, 20, .65);
}