#desktop-fullscreen-btn {
    position: fixed;
    right: 14px;
    bottom: 14px;
    z-index: 9999;
    width: 42px;
    height: 42px;
    border: none;
    border-radius: 12px;
    background: rgba(15, 23, 42, 0.82);
    color: #fff;
    font-size: 1.15rem;
    cursor: pointer;
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.22);
    backdrop-filter: blur(6px);
}

#desktop-fullscreen-btn:hover {
    background: rgba(30, 58, 95, 0.95);
}