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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background: #f5f5f5;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.navbar {
    background: #2c3e50;
    color: white;
    padding: 1rem 0;
    margin-bottom: 2rem;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.brand {
    font-size: 1.5rem;
    font-weight: bold;
}

.nav-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.nav-links a {
    color: white;
    text-decoration: none;
    transition: opacity 0.2s;
}

.nav-links a:hover {
    opacity: 0.8;
}

.username {
    opacity: 0.8;
}

.alert {
    padding: 1rem;
    border-radius: 4px;
    margin-bottom: 1rem;
}

.alert-error {
    background: #fee;
    border: 1px solid #fcc;
    color: #c33;
}

.alert-success {
    background: #efe;
    border: 1px solid #cfc;
    color: #3c3;
}

.alert-info {
    background: #eef;
    border: 1px solid #ccf;
    color: #33c;
}

.alert-warning {
    background: #ffe;
    border: 1px solid #ffc;
    color: #c93;
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    text-decoration: none;
    transition: background 0.2s;
}

.btn-primary {
    background: #3498db;
    color: white;
}

.btn-primary:hover {
    background: #2980b9;
}

.btn-secondary {
    background: #95a5a6;
    color: white;
    margin-left: 0.5rem;
}

.btn-secondary:hover {
    background: #7f8c8d;
}

.btn-danger {
    background: #e74c3c;
    color: white;
}

.btn-danger:hover {
    background: #c0392b;
}

.btn-info {
    background: #17a2b8;
    color: white;
}

.btn-info:hover {
    background: #138496;
}

.btn-sm {
    padding: 0.4rem 0.8rem;
    font-size: 0.9rem;
}

.login-container {
    max-width: 400px;
    margin: 4rem auto;
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
}

.form-group input:focus {
    outline: none;
    border-color: #3498db;
}

.form-group small {
    display: block;
    margin-top: 0.25rem;
    color: #666;
    font-size: 0.875rem;
}

.upload-container {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.drop-zone {
    border: 3px dashed #3498db;
    border-radius: 8px;
    padding: 3rem;
    text-align: center;
    background: #f8f9fa;
    transition: all 0.2s;
    margin: 2rem 0;
}

.drop-zone.drag-over {
    background: #e3f2fd;
    border-color: #2196F3;
}

.drop-zone-content p {
    margin-bottom: 1rem;
    color: #666;
}

.upload-status {
    padding: 1rem;
    border-radius: 4px;
    margin: 1rem 0;
    text-align: center;
    font-weight: 500;
}

.upload-status.uploading {
    background: #fff3cd;
    color: #856404;
}

.upload-status.success {
    background: #d4edda;
    color: #155724;
}

.upload-status.error {
    background: #f8d7da;
    color: #721c24;
}

.files-list {
    margin-top: 2rem;
}

.files-list h2 {
    margin-bottom: 1rem;
}

.no-files {
    text-align: center;
    color: #999;
    padding: 2rem;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: white;
}

table th,
table td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid #ddd;
}

table th {
    background: #f8f9fa;
    font-weight: 600;
    color: #495057;
}

table tr:hover {
    background: #f8f9fa;
}

.admin-container {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.admin-section {
    margin: 2rem 0;
}

.add-user-form {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 4px;
    margin-bottom: 2rem;
}

.add-user-form h3 {
    margin-bottom: 1rem;
}

.form-row {
    display: flex;
    gap: 1rem;
    align-items: flex-end;
}

.form-row .form-group {
    flex: 1;
    margin-bottom: 0;
}

.totp-setup-container {
    max-width: 600px;
    margin: 2rem auto;
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.totp-instructions h2 {
    margin: 2rem 0 1rem;
}

.qr-code {
    text-align: center;
    padding: 2rem;
    background: #f8f9fa;
    border-radius: 4px;
    margin: 1rem 0;
}

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

.secret-key {
    background: #f8f9fa;
    padding: 1rem;
    border-radius: 4px;
    margin: 1rem 0;
    text-align: center;
}

.secret-key code {
    font-size: 1.2rem;
    font-family: 'Courier New', monospace;
    color: #2c3e50;
}

/* Mobile Responsive Styles */

/* Tablet and below (768px) */
@media (max-width: 768px) {
    .container {
        padding: 0 15px;
    }

    .navbar .container {
        flex-direction: column;
        gap: 1rem;
    }

    .nav-links {
        flex-wrap: wrap;
        gap: 1rem;
        justify-content: center;
        font-size: 0.9rem;
    }

    .upload-container,
    .admin-container,
    .login-container {
        padding: 1.5rem;
    }

    .drop-zone {
        padding: 2rem 1rem;
    }

    /* Make tables scrollable */
    .files-list {
        overflow-x: auto;
    }

    table {
        min-width: 600px;
    }

    /* Stack form rows */
    .form-row {
        flex-direction: column;
        gap: 0;
    }

    .form-row .form-group {
        margin-bottom: 1rem;
    }

    /* Larger touch targets for buttons */
    .btn {
        padding: 0.85rem 1.5rem;
        min-height: 44px;
    }

    .btn-sm {
        padding: 0.6rem 1rem;
        min-height: 40px;
        font-size: 0.95rem;
    }
}

/* Mobile phones (480px and below) */
@media (max-width: 480px) {
    .brand {
        font-size: 1.2rem;
    }

    .nav-links {
        font-size: 0.85rem;
        gap: 0.75rem;
    }

    .nav-links a {
        padding: 0.5rem;
    }

    h1 {
        font-size: 1.5rem;
    }

    h2 {
        font-size: 1.3rem;
    }

    .upload-container,
    .admin-container,
    .login-container {
        padding: 1rem;
        border-radius: 4px;
    }

    .drop-zone {
        padding: 1.5rem 0.75rem;
        margin: 1rem 0;
    }

    .drop-zone-content p {
        font-size: 0.9rem;
    }

    /* Make action buttons stack vertically on very small screens */
    table td .btn {
        display: block;
        width: 100%;
        margin-bottom: 0.5rem;
        text-align: center;
    }

    table td .btn:last-child {
        margin-bottom: 0;
    }

    /* Compact table cells */
    table th,
    table td {
        padding: 0.5rem;
        font-size: 0.9rem;
    }

    /* Better mobile table layout */
    .files-list table {
        min-width: 100%;
    }

    /* Hide less critical columns on very small screens */
    table th:nth-child(3),
    table td:nth-child(3) {
        display: none;
    }

    /* Alert messages */
    .alert {
        padding: 0.75rem;
        font-size: 0.9rem;
    }

    /* Forms */
    .form-group input {
        padding: 0.85rem;
        font-size: 16px; /* Prevents zoom on iOS */
    }

    .login-container {
        margin: 2rem auto;
    }

    /* Admin forms */
    .add-user-form {
        padding: 1rem;
    }

    .add-user-form h3 {
        font-size: 1.1rem;
    }
}

/* Very small screens (360px and below) */
@media (max-width: 360px) {
    .container {
        padding: 0 10px;
    }

    .upload-container,
    .admin-container,
    .login-container {
        padding: 0.75rem;
    }

    .nav-links {
        gap: 0.5rem;
        font-size: 0.8rem;
    }

    .btn {
        padding: 0.75rem 1rem;
        font-size: 0.9rem;
    }
}

/* Landscape mobile orientation */
@media (max-width: 768px) and (orientation: landscape) {
    .navbar .container {
        flex-direction: row;
    }

    .nav-links {
        gap: 0.75rem;
        font-size: 0.85rem;
    }

    .drop-zone {
        padding: 1.5rem 1rem;
    }
}

/* Touch-specific improvements */
@media (hover: none) and (pointer: coarse) {
    /* Larger tap targets for touch devices */
    .btn,
    .nav-links a,
    table a {
        min-height: 44px;
        display: inline-flex;
        align-items: center;
        justify-content: center;
    }

    /* Remove hover states on touch devices */
    table tr:hover {
        background: white;
    }

    /* Active states instead */
    .btn:active {
        opacity: 0.8;
        transform: scale(0.98);
    }

    table tr:active {
        background: #f0f0f0;
    }
}

/* Table wrapper for horizontal scroll on mobile */
.table-responsive {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

/* Better table layout on all screen sizes */
@media (max-width: 768px) {
    .table-responsive {
        margin: 0 -15px;
        padding: 0 15px;
    }

    /* Make filename column wrap on mobile */
    table td:first-child {
        max-width: 150px;
        word-wrap: break-word;
        overflow-wrap: break-word;
    }
}