body {
    font-family: Arial, sans-serif;
    background-color: #eef2f5;
    margin: 0;
    padding: 20px;
    font-size: 18px;
}

.card {
    background-color: #fff;
    border-radius: 10px;
    padding: 30px;
    max-width: 100%;
    margin: 0 auto;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    box-sizing: border-box;
}

.card h2 {
    text-align: center;
    color: #2c3e50;
    margin-bottom: 25px;
    font-size: 24px;
}

.field {
    margin-bottom: 15px;
}

.field strong {
    display: block;
    font-weight: bold;
    color: #333;
    font-size: 18px;
}

.field span {
    display: block;
    color: #555;
    font-size: 17px;
}

#qr-reader {
    width: 100%;
    min-height: 300px;
    margin-bottom: 20px;
}

form {
    margin-top: 10px;
    display: flex;
    flex-direction: column;
}

label {
    margin-top: 12px;
    font-weight: bold;
    color: #333;
    font-size: 18px;
}

input[type="text"] {
    width: 100%;
    padding: 14px;
    margin-top: 8px;
    border: 1px solid #ccc;
    border-radius: 6px;
    box-sizing: border-box;
    font-size: 18px;
}

button {
    background-color: #3498db;
    color: white;
    padding: 14px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    margin-top: 20px;
    width: 100%;
    font-size: 18px;
}

button:hover {
    background-color: #2980b9;
}

.message {
    color: red;
    text-align: center;
    margin-top: 15px;
    font-size: 18px;
}

.spinner {
    border: 6px solid #f3f3f3;
    border-top: 6px solid #3498db;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin: 0 auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@media (max-width: 600px) {
    .card {
        padding: 20px;
        margin: 10px;
    }

    input[type="text"], button {
        font-size: 20px;
        padding: 16px;
    }

    .card h2 {
        font-size: 22px;
    }

    #qr-reader {
        min-height: 250px;
    }
}