.scroll-up {
    cursor: pointer;
    position: fixed;
    display: none;
    bottom: 24px;
    right: 24px;
    z-index: 999;
}

#scroll-up-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    color: #111;
    background-color: var(--fourth-color);
    box-shadow: var(--shadow-soft);
    transition: background-color .2s ease, transform .15s ease;
}

#scroll-up-btn:hover,
#scroll-up-btn:focus-visible,
#scroll-up-btn:active {
    opacity: 1;
    background-color: var(--accent-warm);
    transform: translateY(-2px);
    color: #111;
}