.popup-container {
    position: fixed;
    left: 20px;
    bottom: 20px;
    background: linear-gradient(to bottom right, #ffffff, #f8f9fa);
    box-shadow: 0 8px 32px rgba(0,0,0,0.15);
    border-radius: 16px;
    width: 320px;
    z-index: 1000;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid rgba(255,255,255,0.18);
}

@media (max-width: 768px) {
    .popup-container {
        width: 90%;
        left: 5%;
        bottom: 15px;
    }
}

.popup-content {
    padding: 20px;
}

.popup-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    border-bottom: 1px solid rgba(0,0,0,0.05);
    padding-bottom: 15px;
}

.popup-header h3 {
    font-size: 1.25rem;
    color: #333;
    margin: 0;
    font-weight: 600;
}

.close-btn {
    background: none;
    border: none;
    font-size: 28px;
    cursor: pointer;
    color: #666;
    transition: color 0.3s ease;
    padding: 0;
    line-height: 1;
}

.close-btn:hover {
    color: #333;
}

.popup-body p {
    color: #666;
    text-align: center;
    margin-bottom: 15px;
    font-size: 1rem;
}

.qr-code {
    max-width: 200px;
    display: block;
    margin: 15px auto;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    transition: transform 0.3s ease;
}

.qr-code:hover {
    transform: scale(1.02);
}

.expand-btn {
    position: fixed;
    left: 20px;
    bottom: 20px;
    background: linear-gradient(135deg, #007bff, #0056b3);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 25px;
    cursor: pointer;
    z-index: 999;
    font-weight: 500;
    box-shadow: 0 4px 15px rgba(0,123,255,0.3);
    transition: all 0.3s ease;
}

.expand-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0,123,255,0.4);
}

.hidden {
    display: none;
    opacity: 0;
    transform: translateY(20px);
}