/* Main CSS for Lernkarte.com */

:root {
    --primary-color: #667eea;
    --primary-light: #764ba2;
    --primary-dark: #5a67d8;
    --secondary-color: #ff6b6b;
    --secondary-light: #ffa726;
    --secondary-dark: #e53e3e;
    --success-color: #4caf50;
    --danger-color: #f44336;
    --warning-color: #ff9800;
    --info-color: #2196f3;
    --light-color: #f8f9fa;
    --dark-color: #2d3748;
    --gray-color: #718096;
    --gray-light: #e9ecef;
    --gray-dark: #4a5568;
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --border-radius: 8px;
    --box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(45deg, #ff6b6b, #ffa726);
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--dark-color);
    background-color: #f5f7fa;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--primary-dark);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    margin-bottom: 1rem;
    font-weight: 500;
    line-height: 1.2;
    color: var(--dark-color);
}

h1 {
    font-size: 2.5rem;
}

h2 {
    font-size: 2rem;
}

h3 {
    font-size: 1.75rem;
}

h4 {
    font-size: 1.5rem;
}

h5 {
    font-size: 1.25rem;
}

h6 {
    font-size: 1rem;
}

p {
    margin-bottom: 1rem;
}

/* Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* Header */
.header {
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--box-shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    display: flex;
    align-items: center;
}

.logo img {
    height: 40px;
    margin-right: 10px;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

/* Navigation */
.nav {
    display: flex;
    align-items: center;
}

.nav-list {
    display: flex;
    list-style: none;
}

.nav-item {
    position: relative;
    margin-left: 1.5rem;
}

.nav-link {
    color: var(--dark-color);
    font-weight: 500;
    padding: 0.5rem 0;
    display: block;
}

.nav-link:hover {
    color: var(--primary-color);
}

.dropdown {
    position: relative;
}

.dropdown-toggle {
    display: flex;
    align-items: center;
    cursor: pointer;
}

.dropdown-toggle::after {
    content: '▼';
    font-size: 0.7rem;
    margin-left: 0.5rem;
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background-color: #fff;
    box-shadow: var(--box-shadow);
    border-radius: var(--border-radius);
    min-width: 200px;
    display: none;
    z-index: 1000;
}

.dropdown:hover .dropdown-menu {
    display: block;
}

.dropdown-item {
    padding: 0.75rem 1rem;
    display: block;
    color: var(--dark-color);
    border-bottom: 1px solid var(--gray-light);
}

.dropdown-item:last-child {
    border-bottom: none;
}

.dropdown-item:hover {
    background-color: var(--gray-light);
    color: var(--primary-color);
}

/* Mobile menu */
.menu-toggle {
    display: none;
    cursor: pointer;
    font-size: 1.5rem;
}

/* Main content */
.main {
    flex: 1;
    padding: 2rem 0;
}

/* Hero section */
.hero {
    background-color: var(--primary-color);
    color: #fff;
    padding: 4rem 0;
    margin-bottom: 2rem;
    border-radius: var(--border-radius);
    background-image: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
}

.hero-content {
    max-width: 600px;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: #fff;
}

.hero p {
    font-size: 1.1rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

/* Cards */
.card {
    background-color: #fff;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    margin-bottom: 1.5rem;
    overflow: hidden;
    transition: var(--transition);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.card-header {
    padding: 1rem;
    background-color: var(--gray-light);
    border-bottom: 1px solid rgba(0, 0, 0, 0.125);
}

.card-body {
    padding: 1.5rem;
}

.card-footer {
    padding: 1rem;
    background-color: var(--gray-light);
    border-top: 1px solid rgba(0, 0, 0, 0.125);
}

/* Features */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.feature {
    text-align: center;
    padding: 1.5rem;
}

.feature-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    text-align: center;
    white-space: nowrap;
    padding: 0.75rem 1.5rem;
    border-radius: 50px;
    transition: all 0.3s ease;
    cursor: pointer;
    vertical-align: middle;
    user-select: none;
    border: 1px solid transparent;
    padding: 0.5rem 1rem;
    font-size: 1rem;
    line-height: 1.5;
    border-radius: var(--border-radius);
    transition: var(--transition);
    cursor: pointer;
}

.btn:focus {
    outline: 0;
    box-shadow: 0 0 0 0.2rem rgba(74, 107, 175, 0.25);
}

.btn-primary {
    background-color: var(--primary-color);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 40px rgba(255, 107, 107, 0.6);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.2);
    color: var(--dark-color);
    border: 2px solid rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-3px);
}

.btn-success {
    background-color: var(--success-color);
    border-color: var(--success-color);
    color: #fff;
}

.btn-danger {
    background-color: var(--danger-color);
    border-color: var(--danger-color);
    color: #fff;
}

.btn-warning {
    background-color: var(--warning-color);
    border-color: var(--warning-color);
    color: #fff;
}

.btn-info {
    background-color: var(--info-color);
    border-color: var(--info-color);
    color: #fff;
}

.btn-light {
    background-color: var(--light-color);
    border-color: var(--light-color);
    color: var(--dark-color);
}

.btn-dark {
    background-color: var(--dark-color);
    border-color: var(--dark-color);
    color: #fff;
}

.btn-outline-primary {
    background-color: transparent;
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-outline-primary:hover {
    background-color: var(--primary-color);
    color: #fff;
}

.btn-lg {
    padding: 0.75rem 1.5rem;
    font-size: 1.25rem;
}

/* --- Admin UI (centralized) --- */
.admin-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    font-family: var(--font-family);
}

.admin-card {
    border-radius: 12px;
    border: 1px solid rgba(102, 126, 234, 0.2);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
    margin-bottom: 25px;
    background: #fff;
    overflow: hidden;
    transition: var(--transition);
}

.admin-card:hover {
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.15);
}

.admin-card-header {
    padding: 15px 20px;
    border-bottom: 1px solid rgba(102, 126, 234, 0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.admin-card-header h2,
.admin-card-header h3 {
    margin: 0;
    font-weight: 400;
    font-size: 1.2rem;
    color: #333;
}

.admin-card-body {
    padding: 20px;
}

.admin-primary {
    background: var(--gradient-primary);
    color: #fff;
}

.admin-secondary {
    background: linear-gradient(135deg, #6a11cb, #2575fc);
    color: #fff;
}

.admin-info {
    background: linear-gradient(135deg, #2193b0, #6dd5ed);
    color: #fff;
}

.admin-warning {
    background: linear-gradient(135deg, #f6d365, #fda085);
    color: #333;
}

/* Specific gradients used in headers */
.admin-gradient-fields {
    background: linear-gradient(135deg, #43c6ac, #191654);
    color: #fff;
}

.admin-gradient-cards {
    background: linear-gradient(135deg, #ff9966, #ff5e62);
    color: #fff;
}

.admin-btn {
    padding: 8px 16px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    font-weight: 500;
    transition: all 0.2s ease;
}

.admin-btn-light {
    background: rgba(255, 255, 255, 0.9);
    color: #333;
}

.admin-btn-light:hover {
    background: #fff;
    box-shadow: 0 3px 8px rgba(0, 0, 0, 0.1);
}

.admin-btn-primary {
    background: var(--primary-color);
    color: #fff;
}

.admin-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    margin-bottom: 1rem;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

.admin-table thead th {
    background: var(--gradient-primary);
    color: #fff;
    padding: 12px 15px;
    font-weight: 600;
    text-align: left;
    border: none;
    font-size: 0.9rem;
}

.admin-table tbody tr {
    background-color: #fff;
    transition: background-color 0.2s;
}

.admin-table tbody tr:nth-child(odd) {
    background-color: rgba(102, 126, 234, 0.05);
}

.admin-table tbody tr:hover {
    background-color: rgba(102, 126, 234, 0.1);
}

.admin-table td {
    padding: 12px 15px;
    border-top: 1px solid #edf2f7;
    vertical-align: middle;
}

.admin-card-content {
    display: flex;
    align-items: flex-start;
    max-height: 100px;
    overflow-y: auto;
}

.admin-btn-group {
    display: flex;
    gap: 5px;
    justify-content: center;
}

.admin-btn-sm {
    padding: 0.25rem 0.5rem;
    font-size: 0.75rem;
    border-radius: 4px;
}

.admin-badge {
    display: inline-flex;
    align-items: center;
    padding: 0.35em 0.65em;
    font-size: 0.75em;
    font-weight: 600;
    line-height: 1;
    text-align: center;
    white-space: nowrap;
    vertical-align: baseline;
}

.admin-empty-center {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    text-align: center;
    border-radius: 8px;
}

/* Card list styling from admin page */
.card-list-header {
    padding: 10px 15px;
    border-bottom: 1px solid #ddd;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-list-stats {
    display: flex;
    gap: 10px;
    font-size: 0.9rem;
    color: #666;
}

.card-list-items {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 12px;
    padding: 12px;
}

.card-item {
    border: 1px solid #eee;
    border-radius: 8px;
    padding: 12px;
    background: #fff;
    box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}

.card-item .question,
.card-item .answer {
    font-size: 0.95rem;
}

/* Admin list groups */
.admin-list-group {
    border: 1px solid #ddd;
    border-radius: 4px;
}
.admin-list-group-item {
    padding: 12px;
    border-bottom: 1px solid #ddd;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
}
.admin-list-group-item:last-child { border-bottom: none; }
.admin-list-group-item-action { cursor: pointer; text-decoration: none; color: inherit; }
.admin-list-group-item-action:hover { background: #f8f9fa; }
.admin-list-group-item.active { background: var(--primary-color); color: #fff; }

/* Badge variants */
.admin-badge-primary { background: var(--primary-color); color: #fff; border-radius: 999px; padding: 0.25rem 0.5rem; }
.admin-badge-info { background: #2193b0; color: #fff; border-radius: 999px; padding: 0.25rem 0.5rem; }

/* Background helpers */
.bg-primary { background: var(--primary-color) !important; color: #fff !important; }
.bg-info { background: #2193b0 !important; color: #fff !important; }

/* Max-height scroll helpers */
.maxh-300 { max-height: 300px; overflow-y: auto; }
.maxh-500 { max-height: 500px; overflow-y: auto; }
.maxh-600 { max-height: 600px; overflow-y: auto; }

/* Admin search bar */
.admin-search { position: relative; display: flex; align-items: center; }
.admin-search i { position: absolute; left: 10px; color: #888; }
.admin-search input {
    width: 100%;
    padding: 10px 12px 10px 32px;
    border: 1px solid #ddd;
    border-radius: 6px;
}

.admin-search-actions {
    position: absolute;
    right: 5px;
    top: 50%;
    transform: translateY(-50%);
    display: flex;
    gap: 6px;
}

/* Card list items */
.card-list-item { padding: 10px 15px; border-bottom: 1px solid #eee; }
.card-list-item:hover { background-color: #f9f9f9; }

/* Multiple-choice result states (used in dashboard/learn.php) */
.mc-option.selected {
    border-color: #667eea !important;
    box-shadow: 0 2px 8px rgba(102, 126, 234, 0.15) !important;
}
.mc-option.correct {
    border-color: #28a745 !important;
    background: rgba(40, 167, 69, 0.08) !important;
}
.mc-option.incorrect {
    border-color: #dc3545 !important;
    background: rgba(220, 53, 69, 0.08) !important;
}
.card-number { display: inline-block; width: 30px; font-weight: bold; }
.card-actions { float: right; }
.card-actions .btn { margin-left: 5px; }

.btn-sm {
    padding: 0.25rem 0.5rem;
    font-size: 0.875rem;
}

.btn-block {
    display: block;
    width: 100%;
}

/* Layout utilities */
.d-flex { display: flex; }
.align-center { align-items: center; }
.justify-between { justify-content: space-between; }
.flex-1 { flex: 1 1 auto; }
.gap-5 { gap: 5px; }
.gap-10 { gap: 10px; }
.mb-3 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 1.5rem; }
.mt-2 { margin-top: 10px; }
.mb-1 { margin-bottom: 5px; }
.mb-2 { margin-bottom: 10px; }
.m-0 { margin: 0; }
.nowrap { white-space: nowrap; }
.mr-8 { margin-right: 8px; }
.mr-4 { margin-right: 4px; }
.ml-5 { margin-left: 5px; }

/* Typography utilities */
.fs-85 { font-size: 0.85em; }
.fs-24 { font-size: 24px; }
.fs-110 { font-size: 1.1em; }

/* Text color utilities */
.text-333 { color: #333; }
.text-555 { color: #555; }
.text-666 { color: #666; }
.text-999 { color: #999; }
.text-brand { color: #667eea; }

/* Visibility utilities */
.opacity-50 { opacity: 0.5; }

/* Centered panel utility */
.centered-panel {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  text-align: center;
  border-radius: 8px;
}

/* Backward-compatible admin empty state class */
.admin-empty-center {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  text-align: center;
  border-radius: 8px;
}

/* Button utility for gradient primary action */
.btn-gradient {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    border: none;
    border-radius: 12px;
    padding: 8px 20px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}
.btn-gradient:hover { filter: brightness(1.02); }
.btn-gradient:active { transform: translateY(1px); }

/* Utility: gradient background (brand) */
.bg-gradient-primary {
  background: var(--gradient-primary) !important;
}

/* Surface panel container */
.surface-panel {
    background: #fff;
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
    border: 1px solid rgba(240, 240, 240, 0.8);
}

/* Forms */
.form-group {
    margin-bottom: 1rem;
}

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

.form-control {
    display: block;
    width: 100%;
    padding: 0.5rem 0.75rem;
    font-size: 1rem;
    line-height: 1.5;
    color: var(--dark-color);
    background-color: #fff;
    background-clip: padding-box;
    border: 1px solid var(--gray-light);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.form-control:focus {
    color: var(--dark-color);
    background-color: #fff;
    border-color: var(--primary-light);
    outline: 0;
    box-shadow: 0 0 0 0.2rem rgba(74, 107, 175, 0.25);
}

/* Accessible focus outlines for interactive elements */
a:focus-visible,
button:focus-visible,
.btn:focus-visible,
[role="button"]:focus-visible,
input[type="checkbox"]:focus-visible,
input[type="radio"]:focus-visible,
select:focus-visible,
textarea:focus-visible {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.25);
}

/* Utility: visually hidden (screen-reader only) */
.visually-hidden,
.sr-only {
    position: absolute !important;
    width: 1px !important;
    height: 1px !important;
    padding: 0 !important;
    margin: -1px !important;
    overflow: hidden !important;
    clip: rect(0 0 0 0) !important;
    white-space: nowrap !important;
    border: 0 !important;
}

/* Make skip link visible when focused */
.skip-link:focus,
.skip-link:focus-visible {
    position: fixed !important;
    top: 10px !important;
    left: 10px !important;
    width: auto !important;
    height: auto !important;
    padding: 10px 14px !important;
    margin: 0 !important;
    clip: auto !important;
    white-space: normal !important;
    background: #2d3748;
    color: #fff;
    border-radius: 6px;
    z-index: 2000;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}

.form-text {
    display: block;
    margin-top: 0.25rem;
    font-size: 0.875rem;
    color: var(--gray-color);
}

/* Alerts */
.alert {
    position: relative;
    padding: 1rem;
    margin-bottom: 1rem;
    border: 1px solid transparent;
    border-radius: var(--border-radius);
}

.alert-success {
    color: #155724;
    background-color: #d4edda;
    border-color: #c3e6cb;
}

.alert-danger {
    color: #721c24;
    background-color: #f8d7da;
    border-color: #f5c6cb;
}

.alert-warning {
    color: #856404;
    background-color: #fff3cd;
    border-color: #ffeeba;
}

.alert-info {
    color: #0c5460;
    background-color: #d1ecf1;
    border-color: #bee5eb;
}

/* Learning Card */
.learning-card {
    perspective: 1000px;
    height: 300px;
    margin-bottom: 2rem;
}

.learning-card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.6s;
    transform-style: preserve-3d;
}

.learning-card.flipped .learning-card-inner {
    transform: rotateY(180deg);
}

.learning-card-front, .learning-card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    background-color: #fff;
}

.learning-card-back {
    transform: rotateY(180deg);
    background-color: var(--primary-light);
    color: #fff;
}

/* Multiple choice */
.multiple-choice {
    margin-bottom: 2rem;
}

.multiple-choice-question {
    font-size: 1.25rem;
    margin-bottom: 1.5rem;
    font-weight: 500;
}

.multiple-choice-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.multiple-choice-option {
    padding: 1rem;
    border: 2px solid var(--gray-light);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
}

.multiple-choice-option:hover {
    border-color: var(--primary-light);
}

.multiple-choice-option.selected {
    border-color: var(--primary-color);
    background-color: rgba(74, 107, 175, 0.1);
}

.multiple-choice-option.correct {
    border-color: var(--success-color);
    background-color: rgba(76, 175, 80, 0.1);
}

.multiple-choice-option.incorrect {
    border-color: var(--danger-color);
    background-color: rgba(244, 67, 54, 0.1);
}

/* Dashboard */
.dashboard-header {
    margin-bottom: 2rem;
}

.dashboard-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background-color: #fff;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 1.5rem;
    text-align: center;
}

.stat-card-icon {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.stat-card-value {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.stat-card-label {
    color: var(--gray-color);
    font-size: 0.9rem;
}

.quick-actions {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.quick-action {
    background-color: #fff;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 1.5rem;
    text-align: center;
    transition: var(--transition);
}

.quick-action:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.quick-action-icon {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

/* Footer */
.footer {
    background: var(--gradient-primary);
    color: white;
    padding: 3rem 0 1rem;
    margin-top: auto;
    position: relative;
    overflow: hidden;
}

.footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="0.5"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.footer-logo {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #fff;
}

.footer-links h4 {
    color: #fff;
    margin-bottom: 1rem;
}

.footer-links ul {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
}

.footer-links a:hover {
    color: #fff;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    margin-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.7);
}

/* Utilities */
.text-center {
    text-align: center;
}

.text-right {
    text-align: right;
}

.text-primary {
    color: var(--primary-color);
}

.text-secondary {
    color: var(--secondary-color);
}

.text-success {
    color: var(--success-color);
}

.text-danger {
    color: var(--danger-color);
}

.text-warning {
    color: var(--warning-color);
}

.text-info {
    color: var(--info-color);
}

.bg-primary {
    background-color: var(--primary-color);
    color: #fff;
}

.bg-secondary {
    background-color: var(--secondary-color);
    color: #fff;
}

.bg-success {
    background-color: var(--success-color);
    color: #fff;
}

.bg-danger {
    background-color: var(--danger-color);
    color: #fff;
}

.bg-warning {
    background-color: var(--warning-color);
    color: #fff;
}

.bg-info {
    background-color: var(--info-color);
    color: #fff;
}

.bg-light {
    background-color: var(--light-color);
}

.bg-dark {
    background-color: var(--dark-color);
    color: #fff;
}

.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 1rem; }
.mt-4 { margin-top: 1.5rem; }
.mt-5 { margin-top: 3rem; }

.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 1.5rem; }
.mb-5 { margin-bottom: 3rem; }

.ml-1 { margin-left: 0.25rem; }
.ml-2 { margin-left: 0.5rem; }
.ml-3 { margin-left: 1rem; }
.ml-4 { margin-left: 1.5rem; }
.ml-5 { margin-left: 3rem; }

.mr-1 { margin-right: 0.25rem; }
.mr-2 { margin-right: 0.5rem; }
.mr-3 { margin-right: 1rem; }
.mr-4 { margin-right: 1.5rem; }
.mr-5 { margin-right: 3rem; }

.p-1 { padding: 0.25rem; }
.p-2 { padding: 0.5rem; }
.p-3 { padding: 1rem; }
.p-4 { padding: 1.5rem; }
.p-5 { padding: 3rem; }

.pt-1 { padding-top: 0.25rem; }
.pt-2 { padding-top: 0.5rem; }
.pt-3 { padding-top: 1rem; }
.pt-4 { padding-top: 1.5rem; }
.pt-5 { padding-top: 3rem; }

.pb-1 { padding-bottom: 0.25rem; }
.pb-2 { padding-bottom: 0.5rem; }
.pb-3 { padding-bottom: 1rem; }
.pb-4 { padding-bottom: 1.5rem; }
.pb-5 { padding-bottom: 3rem; }

.pl-1 { padding-left: 0.25rem; }
.pl-2 { padding-left: 0.5rem; }
.pl-3 { padding-left: 1rem; }
.pl-4 { padding-left: 1.5rem; }
.pl-5 { padding-left: 3rem; }

.pr-1 { padding-right: 0.25rem; }
.pr-2 { padding-right: 0.5rem; }
.pr-3 { padding-right: 1rem; }
.pr-4 { padding-right: 1.5rem; }
.pr-5 { padding-right: 3rem; }

.d-none { display: none; }
.d-block { display: block; }
.d-flex { display: flex; }
.d-inline { display: inline; }
.d-inline-block { display: inline-block; }

.flex-row { flex-direction: row; }
.flex-column { flex-direction: column; }
.justify-content-start { justify-content: flex-start; }
.justify-content-end { justify-content: flex-end; }
.justify-content-center { justify-content: center; }
.justify-content-between { justify-content: space-between; }
.justify-content-around { justify-content: space-around; }
.align-items-start { align-items: flex-start; }
.align-items-end { align-items: flex-end; }
.align-items-center { align-items: center; }
.align-items-baseline { align-items: baseline; }
.align-items-stretch { align-items: stretch; }

.w-25 { width: 25%; }
.w-50 { width: 50%; }
.w-75 { width: 75%; }
.w-100 { width: 100%; }

.h-25 { height: 25%; }
.h-50 { height: 50%; }
.h-75 { height: 75%; }
.h-100 { height: 100%; }

.rounded { border-radius: var(--border-radius); }
.shadow { box-shadow: var(--box-shadow); }

/* Utility: Brand gradients and helpers */
.bg-gradient-primary {
    background: var(--gradient-primary) !important;
    color: #fff;
}

.btn-gradient {
    background: var(--gradient-primary);
    color: #fff;
    border: none;
    transition: var(--transition);
}
.btn-gradient:hover {
    filter: brightness(1.03);
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(102, 126, 234, 0.3);
}
.btn-gradient:focus {
    outline: 0;
    box-shadow: 0 0 0 0.2rem rgba(102, 126, 234, 0.35);
}

.text-brand { color: var(--primary-color) !important; }
.align-center { align-items: center; }
.gap-10 { gap: 10px; }
.gap-5 { gap: 5px; }
.flex-1 { flex: 1 1 0%; }
.nowrap { white-space: nowrap; }

/* Utility: Alerts */
.alert {
    padding: 1rem 1.25rem;
    margin-bottom: 1.25rem;
    border-radius: 8px;
    border: none;
}
.alert-danger {
    background: rgba(244, 67, 54, 0.1);
    border-left: 4px solid #f44336;
    color: #d32f2f;
}
.alert-success {
    background: rgba(76, 175, 80, 0.1);
    border-left: 4px solid #4caf50;
    color: #2e7d32;
}
.alert-warning {
    background: rgba(255, 193, 7, 0.1);
    border-left: 4px solid #ffc107;
    color: #f57c00;
}
.alert-info {
    background: #d1ecf1;
    border-left: 4px solid #17a2b8;
    color: #0c5460;
}

/* Utility: Buttons (soft/outline/icon) */
.btn-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: 8px;
}

.btn-soft-success {
    background: rgba(76, 175, 80, 0.1);
    color: #2e7d32;
    border: 1px solid rgba(76, 175, 80, 0.2);
}
.btn-soft-success:hover { background: rgba(76, 175, 80, 0.15); }

.btn-soft-danger {
    background: rgba(244, 67, 54, 0.1);
    color: #d32f2f;
    border: 1px solid rgba(244, 67, 54, 0.2);
}
.btn-soft-danger:hover { background: rgba(244, 67, 54, 0.15); }

.btn-soft-warning {
    background: rgba(255, 152, 0, 0.1);
    color: #f57c00;
    border: 1px solid rgba(255, 152, 0, 0.2);
}
.btn-soft-warning:hover { background: rgba(255, 152, 0, 0.15); }

.btn-outline-brand {
    background: #fff;
    color: var(--primary-color);
    border: 1px solid rgba(102, 126, 234, 0.2);
}
.btn-outline-brand:hover { background: rgba(102, 126, 234, 0.05); }

/* Utility: Pagination */
.pagination { display: flex; gap: 0.5rem; align-items: center; }
.page-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 10px;
    background: #fff;
    color: #333;
    border: 1px solid rgba(102, 126, 234, 0.2);
    transition: var(--transition);
    text-decoration: none;
}
.page-link:hover { background: rgba(102, 126, 234, 0.08); transform: translateY(-2px); }
.page-link-active { background: var(--gradient-primary); color: #fff !important; font-weight: 600; box-shadow: 0 4px 10px rgba(102, 126, 234, 0.2); }

/* Admin: Components migrated from admin/manage_cards.php */
.admin-container { max-width: 1200px; margin: 0 auto; padding: 20px; font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; }
.admin-card { border-radius: 12px; border: 1px solid rgba(102, 126, 234, 0.2); box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05); margin-bottom: 25px; background: #fff; overflow: hidden; transition: var(--transition); }
.admin-card:hover { box-shadow: 0 6px 20px rgba(102, 126, 234, 0.15); }
.admin-card-header { padding: 15px 20px; border-bottom: 1px solid rgba(102, 126, 234, 0.1); display: flex; justify-content: space-between; align-items: center; }
.admin-card-header h2, .admin-card-header h3 { margin: 0; font-weight: 400; font-size: 1.2rem; color: #333; }
.admin-card-body { padding: 20px; }
.admin-primary { background: var(--gradient-primary); color: #fff; }
.admin-secondary { background: linear-gradient(135deg, #6a11cb, #2575fc); color: #fff; }
.admin-info { background: linear-gradient(135deg, #2193b0, #6dd5ed); color: #fff; }
.admin-warning { background: linear-gradient(135deg, #f6d365, #fda085); color: #333; }

.admin-btn { padding: 8px 16px; border: none; border-radius: 6px; cursor: pointer; text-decoration: none; display: inline-block; font-weight: 500; transition: var(--transition); }
.admin-btn-light { background: rgba(255, 255, 255, 0.9); color: #333; }
.admin-btn-light:hover { background: #fff; box-shadow: 0 3px 8px rgba(0, 0, 0, 0.1); }
.admin-btn-primary { background: var(--primary-color); color: #fff; }

.admin-table { width: 100%; border-collapse: separate; border-spacing: 0; margin-bottom: 1rem; border-radius: 8px; overflow: hidden; box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05); }
.admin-table thead th { background: var(--gradient-primary); color: #fff; padding: 12px 15px; font-weight: 600; text-align: left; border: none; font-size: 0.9rem; }
.admin-table tbody tr { background-color: #fff; transition: background-color 0.2s; }
.admin-table tbody tr:nth-child(odd) { background-color: rgba(102, 126, 234, 0.05); }
.admin-table tbody tr:hover { background-color: rgba(102, 126, 234, 0.1); }
.admin-table td { padding: 12px 15px; border-top: 1px solid #edf2f7; vertical-align: middle; }

.admin-card-content { display: flex; align-items: flex-start; max-height: 100px; overflow-y: auto; }
.admin-btn-group { display: flex; gap: 5px; justify-content: center; }
.admin-btn-sm { padding: 0.25rem 0.5rem; font-size: 0.75rem; border-radius: 4px; }
.admin-badge { display: inline-flex; align-items: center; padding: 0.35em 0.65em; font-size: 0.75em; font-weight: 600; line-height: 1; white-space: nowrap; }
.admin-badge-primary { background: rgba(102, 126, 234, 0.15); color: var(--primary-color); border: 1px solid rgba(102, 126, 234, 0.2); border-radius: 999px; }
.admin-badge-info { background: rgba(33, 147, 176, 0.15); color: #2193b0; border: 1px solid rgba(33, 147, 176, 0.25); border-radius: 999px; }

.admin-list-group { border: 1px solid rgba(0,0,0,0.08); border-radius: 8px; overflow: hidden; }
.admin-list-group-item { padding: 12px 15px; border-bottom: 1px solid rgba(0,0,0,0.06); display: block; color: inherit; text-decoration: none; }
.admin-list-group-item:last-child { border-bottom: none; }
.admin-list-group-item-action:hover { background: rgba(0,0,0,0.03); }
.admin-list-group-item.active { background: var(--gradient-primary); color: #fff; }
.admin-empty-center { text-align: center; padding: 2rem 1rem; color: #666; }
.maxh-300 { max-height: 300px; overflow: auto; }
.maxh-500 { max-height: 500px; overflow: auto; }
.maxh-600 { max-height: 600px; overflow: auto; }

.admin-alert { padding: 12px 16px; border-radius: 8px; display: flex; align-items: center; }
.admin-alert i { margin-right: 10px; font-size: 18px; }
.admin-alert-info { background: rgba(33, 147, 176, 0.1); color: #2193b0; border-left: 4px solid #2193b0; }
.admin-alert-danger { background: rgba(220, 53, 69, 0.1); color: #dc3545; border-left: 4px solid #dc3545; }

.admin-search { position: relative; margin-bottom: 20px; }
.admin-search input { width: 100%; padding: 10px 15px 10px 40px; border: 1px solid rgba(102, 126, 234, 0.2); border-radius: 8px; font-size: 14px; transition: var(--transition); }
.admin-search input:focus { outline: none; border-color: var(--primary-color); box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.2); }
.admin-search i { position: absolute; left: 15px; top: 50%; transform: translateY(-50%); color: var(--primary-color); }

.card-list-header { padding: 12px 15px; font-weight: 600; border-bottom: 1px solid rgba(0,0,0,0.06); }
.card-list-items { padding: 0; }
.card-list-item { padding: 12px 15px; border-bottom: 1px solid rgba(0,0,0,0.06); display: flex; align-items: center; gap: 12px; }
.card-number { width: 28px; text-align: right; margin-right: 6px; color: #666; }
.card-actions .btn { margin-left: 6px; }

/* Admin search actions */
.admin-search-actions { margin-top: 10px; display: flex; gap: 10px; flex-wrap: wrap; }

/* Additional admin badge variants */
.admin-badge-success { background: rgba(40, 167, 69, 0.12); color: #28a745; border: 1px solid rgba(40, 167, 69, 0.2); border-radius: 999px; }
.admin-badge-warning { background: rgba(253, 126, 20, 0.12); color: #fd7e14; border: 1px solid rgba(253, 126, 20, 0.2); border-radius: 999px; }
.admin-badge-danger { background: rgba(220, 53, 69, 0.12); color: #dc3545; border: 1px solid rgba(220, 53, 69, 0.2); border-radius: 999px; }
.admin-badge-secondary { background: rgba(108, 117, 125, 0.12); color: #6c757d; border: 1px solid rgba(108, 117, 125, 0.2); border-radius: 999px; }

/* Generic panel utilities */
.panel { border-radius: 20px; padding: 2rem; position: relative; overflow: hidden; box-shadow: 0 15px 50px rgba(102, 126, 234, 0.2); margin-bottom: 2rem; }
.panel-overlay { position: absolute; inset: 0; background-color: rgba(255, 255, 255, 0.1); opacity: 0.3; }
.text-shadow-soft { text-shadow: 0 2px 10px rgba(0,0,0,0.2); }
.max-w-900 { max-width: 900px; }
.mx-auto { margin-left: auto; margin-right: auto; }

/* Modern form controls */
.input-modern, .select-modern { border-radius: 12px; border: 2px solid rgba(102, 126, 234, 0.2); padding: 12px 16px; transition: var(--transition); }
.input-modern:focus, .select-modern:focus { border-color: var(--primary-color); box-shadow: 0 0 0 0.2rem rgba(102, 126, 234, 0.25); outline: none; }

/* Text utilities */
.text-white-soft { color: rgba(255, 255, 255, 0.9); }

/* Surface card */
.surface-card { background: #fff; border-radius: 16px; padding: 2rem; box-shadow: 0 10px 30px rgba(0,0,0,0.05); border: 1px solid rgba(240, 240, 240, 0.8); }

/* --- Flashcard 3D Flip Animation --- */
.flashcard-3d { position: relative; -webkit-perspective: 1000px; perspective: 1000px; }
.flashcard-3d .flashcard-inner {
  position: relative;
  width: 100%;
  min-height: 220px;
  -webkit-transition: -webkit-transform 0.6s ease; transition: transform 0.6s ease;
  -webkit-transform-style: preserve-3d; transform-style: preserve-3d;
  cursor: pointer;
}
.flashcard-3d.is-flipped .flashcard-inner { -webkit-transform: rotateY(180deg); transform: rotateY(180deg); }
.flashcard-3d .flashcard-face {
  position: absolute; top: 0; left: 0; width: 100%; height: 100%;
  display: flex; flex-direction: column; justify-content: center;
  -webkit-backface-visibility: hidden; backface-visibility: hidden;
}
.flashcard-3d .flashcard-front {
  -webkit-transform: rotateY(0deg);
  transform: rotateY(0deg);
  z-index: 2;
  will-change: transform;
}
.flashcard-3d .flashcard-back-face { -webkit-transform: rotateY(180deg); transform: rotateY(180deg); }
.flashcard-3d .flashcard-content { padding: 1.25rem; }
.flashcard-3d .tap-instruction { border-top: 1px solid rgba(0,0,0,0.06); padding: 0.75rem 1.25rem; font-size: 0.9rem; color: #6b7280; }

/* Z-Index-Umschaltung statt Visibility, um Rendering-Probleme zu vermeiden */
.flashcard-3d .flashcard-front { z-index: 2; }
.flashcard-3d .flashcard-back-face { z-index: 1; }
.flashcard-3d.is-flipped .flashcard-front { z-index: 1; }
.flashcard-3d.is-flipped .flashcard-back-face { z-index: 2; }

/* Responsive */
@media (max-width: 992px) {
    .container {
        max-width: 960px;
    }
}

@media (max-width: 768px) {
    .container {
        max-width: 720px;
    }
    
    .menu-toggle {
        display: block;
    }
    
    .nav-list {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 80%;
        height: calc(100vh - 70px);
        background-color: #fff;
        flex-direction: column;
        align-items: flex-start;
        padding: 1rem;
        transition: var(--transition);
        box-shadow: var(--box-shadow);
        overflow-y: auto;
    }
    
    .nav-list.active {
        left: 0;
    }
    
    .nav-item {
        margin: 0.5rem 0;
        width: 100%;
    }
    
    .dropdown-menu {
        position: static;
        box-shadow: none;
        display: none;
        width: 100%;
        padding-left: 1rem;
    }
    
    .dropdown.active .dropdown-menu {
        display: block;
    }
    
    .dropdown-toggle::after {
        content: '+';
    }
    
    .dropdown.active .dropdown-toggle::after {
        content: '-';
    }
}

@media (max-width: 576px) {
    .container {
        max-width: 100%;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    h2 {
        font-size: 1.75rem;
    }
    
    h3 {
        font-size: 1.5rem;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    .features {
        grid-template-columns: 1fr;
    }
    
    .dashboard-stats,
    .quick-actions {
        grid-template-columns: 1fr;
    }
    
    .multiple-choice-options {
        grid-template-columns: 1fr;
    }
}