:root {
        --primary: #4CAF50;
        --success: #28a745;
        --danger: #dc3545;
        --warning: #ffc107;
        --info: #17a2b8;
        --light: #f8f9fa;
        --dark: #343a40;
    }

    body {
        font-family: 'Roboto', 'Segoe UI', Arial, sans-serif;
        background-color: #f5f5f5;
    }

    .container-fluid {
        max-width: 1000px;
        margin: auto;
        padding: 20px;
    }

    .card {
        border: none;
        border-radius: 16px;
        box-shadow: 0 4px 12px rgba(0,0,0,0.1);
        overflow: hidden;
        margin-bottom: 20px;
    }

    .card-header {
        background: linear-gradient(135deg, var(--primary), #66bb6a);
        color: white;
        padding: 1.5rem;
        text-align: center;
        border-bottom: none;
    }

    .card-header h4 {
        margin: 0;
        font-weight: 600;
        font-size: 1.5rem;
    }

    .form-control, .form-select {
        border-radius: 8px;
        padding: 10px 12px;
        font-size: 14px;
    }

    .form-label {
        font-weight: 600;
        color: #333;
        margin-bottom: 6px;
    }

    .btn-success {
        background-color: var(--success);
        border: none;
        border-radius: 12px;
        padding: 10px 24px;
        font-weight: 500;
        box-shadow: 0 2px 4px rgba(0,0,0,0.2);
        transition: all 0.2s;
    }

    .btn-success:hover {
        background-color: #218838;
        transform: translateY(-1px);
    }

    .btn-warning {
        background-color: #ffc107;
        color: #212529;
        border: none;
        border-radius: 12px;
        padding: 10px 24px;
        font-weight: 500;
    }

    .btn-warning:hover {
        background-color: #e0a800;
    }

    .form-check-label {
        font-weight: normal;
        cursor: pointer;
        user-select: none;
    }

    .highlight {
        color: #d32f2f;
        font-weight: bold;
    }

    .qrcode-container {
        text-align: center;
        margin: 20px 0;
    }

    .qrcode-container img {
        max-width: 180px;
        border: 2px solid #ddd;
        border-radius: 12px;
        padding: 8px;
        background: white;
    }

    .section-title {
        font-size: 1.1rem;
        font-weight: 600;
        color: var(--primary);
        border-bottom: 2px solid var(--primary);
        padding-bottom: 8px;
        margin: 24px 0 16px;
    }

    @media (max-width: 768px) {
        .card-header h4 {
            font-size: 1.3rem;
        }
        .form-control, .form-select {
            font-size: 13px;
        }
        .btn {
            width: 100%;
            margin-bottom: 8px;
        }
    }