* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.container {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.content {
    text-align: center;
    background: white;
    padding: 60px 40px;
    border-radius: 15px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
    max-width: 400px;
}

h1 {
    font-size: 48px;
    color: #333;
    margin-bottom: 50px;
    font-weight: 600;
}

.buttons {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.btn {
    padding: 14px 30px;
    font-size: 16px;
    font-weight: 600;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
}

.btn-primary {
    background-color: #667eea;
    color: white;
}

.btn-primary:hover {
    background-color: #5568d3;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    background-color: #764ba2;
    color: white;
}

.btn-secondary:hover {
    background-color: #63408a;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(118, 75, 162, 0.4);
}

/* ============================================
   RESPONSIVE DESIGN - MEDIA QUERIES
   ============================================ */

/* MOBILE DEVICES (Extra Small) - max 576px */
@media (max-width: 576px) {
    body {
        height: 100%;
        min-height: 100vh;
    }

    .container {
        height: auto;
        min-height: 100vh;
        padding: 20px 10px;
    }

    .content {
        padding: 30px 15px;
        max-width: 100%;
    }

    h1 {
        font-size: 28px;
        margin-bottom: 25px;
    }

    .btn {
        padding: 12px 16px;
        font-size: 13px;
        width: 100%;
    }

    /* Form containers on mobile */
    .form-container {
        padding: 25px 15px !important;
        max-width: 100% !important;
        border-radius: 10px;
    }

    .form-group input,
    .form-group select,
    .form-group textarea {
        font-size: 16px !important;
        padding: 10px !important;
    }

    .form-group label {
        font-size: 13px;
    }

    /* Admin panel on mobile */
    .admin-container {
        padding: 20px 12px !important;
        max-width: 100% !important;
    }

    .admin-header {
        flex-direction: column;
        text-align: center;
        gap: 10px;
    }

    /* Ensure buttons are full width on mobile */
    .btn-submit,
    .btn-group {
        width: 100%;
    }

    .btn-group button {
        width: 100% !important;
        margin: 8px 0 !important;
    }

    /* QR Code sizing */
    .qr-code-container {
        width: 100%;
    }

    .qr-code-container img {
        max-width: 100%;
        height: auto;
    }
}

/* MOBILE DEVICES (Small) - 576px to 768px */
@media (min-width: 577px) and (max-width: 768px) {
    .content {
        padding: 40px 25px;
        max-width: 100%;
    }

    h1 {
        font-size: 36px;
        margin-bottom: 30px;
    }

    .btn {
        padding: 12px 24px;
        font-size: 14px;
    }

    .form-container {
        padding: 35px 20px !important;
        max-width: 100% !important;
    }

    .admin-container {
        padding: 30px 20px !important;
        max-width: 100% !important;
    }

    .admin-header {
        flex-direction: column;
        text-align: center;
    }
}

/* TABLETS (Medium) - 769px to 992px */
@media (min-width: 769px) and (max-width: 992px) {
    .content {
        padding: 50px 35px;
        max-width: 95%;
    }

    h1 {
        font-size: 42px;
        margin-bottom: 40px;
    }

    .form-container {
        padding: 40px 25px !important;
        max-width: 90% !important;
    }

    .admin-container {
        padding: 40px 25px !important;
        max-width: 90% !important;
    }

    .admin-header {
        flex-direction: row;
    }
}

/* DESKTOP (Large) - 993px to 1200px */
@media (min-width: 993px) and (max-width: 1200px) {
    .content {
        padding: 60px 40px;
        max-width: 450px;
    }

    .form-container {
        padding: 40px 30px !important;
        max-width: 550px !important;
    }

    .admin-container {
        padding: 40px 30px !important;
        max-width: 950px !important;
    }
}

/* LARGE DESKTOP (XL) - 1201px and above */
@media (min-width: 1201px) {
    .content {
        padding: 60px 40px;
        max-width: 500px;
    }

    .form-container {
        padding: 40px 40px !important;
        max-width: 600px !important;
    }

    .admin-container {
        padding: 40px 40px !important;
        max-width: 1000px !important;
    }
}