body, html {
    height: 100%;
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #f4f4f9;
}

#qr-container {
    padding: 15px;
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}