/* Reset und Basis-Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #1e40af;
    --primary-hover: #1e3a8a;
    --secondary-color: #3b82f6;
    --success-color: #22c55e;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    --neutral-color: #6b7280;
    --bg-color: #f3f4f6;
    --card-bg: #ffffff;
    --text-color: #1f2937;
    --border-color: #e5e7eb;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
header {
    text-align: center;
    color: white;
    margin-bottom: 30px;
    padding: 20px 0;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* Screen Management */
.screen {
    display: none;
}

.screen.active {
    display: block;
}

.hidden {
    display: none !important;
}

/* Buttons */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

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

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

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

.btn-back {
    background-color: var(--neutral-color);
    color: white;
}

.btn-back:hover {
    background-color: #4b5563;
}

.btn-danger {
    background-color: var(--error-color);
    color: white;
}

.btn-danger:hover {
    background-color: #dc2626;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* Mode Selection */
.mode-selection {
    background: var(--card-bg);
    padding: 40px;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
}

.mode-selection h2 {
    text-align: center;
    margin-bottom: 30px;
    color: var(--text-color);
}

.mode-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 20px;
}

.mode-card {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    padding: 30px;
    border-radius: 12px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    color: white;
}

.mode-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.mode-icon {
    font-size: 3rem;
    margin-bottom: 15px;
}

.mode-card h3 {
    margin-bottom: 10px;
    font-size: 1.5rem;
}

.mode-card p {
    opacity: 0.9;
    font-size: 0.95rem;
}

/* Category Selection */
.category-selection {
    background: var(--card-bg);
    padding: 40px;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    margin-top: 20px;
}

.category-selection h2 {
    text-align: center;
    margin-bottom: 30px;
}

.category-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
}

.category-buttons .btn {
    width: 100%;
}

/* Fachkategorien */
.fach-categories-section {
    margin-top: 30px;
    border-top: 2px solid var(--border-color);
    padding-top: 20px;
}

.fach-categories-title {
    text-align: center;
    color: var(--text-color);
    margin-bottom: 20px;
    font-size: 1.1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--neutral-color);
}

.fach-group {
    margin-bottom: 20px;
}

.fach-group-header {
    font-weight: 700;
    font-size: 1rem;
    color: var(--primary-color);
    margin-bottom: 10px;
    padding: 6px 0;
    border-bottom: 1px solid var(--border-color);
}

.fach-section-label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--neutral-color);
    margin: 10px 0 6px 0;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.fach-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 10px;
    margin-bottom: 8px;
}

.btn-fach {
    background-color: #eff6ff;
    color: var(--primary-color);
    border: 2px solid #bfdbfe;
    padding: 10px 14px;
    font-size: 0.9rem;
    font-weight: 500;
    text-align: left;
}

.btn-fach:hover {
    background-color: #dbeafe;
    border-color: var(--secondary-color);
    color: var(--primary-hover);
}

@media (max-width: 768px) {
    .fach-buttons {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 480px) {
    .fach-buttons {
        grid-template-columns: 1fr;
    }
}

/* Progress Bar */
.progress-bar {
    background: var(--card-bg);
    padding: 15px 20px;
    border-radius: 12px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
    position: relative;
    height: 60px;
}

.progress-fill {
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    background: linear-gradient(90deg, var(--success-color), #16a34a);
    border-radius: 12px;
    transition: width 0.3s ease;
    width: 0%;
}

.progress-text {
    position: relative;
    z-index: 1;
    font-weight: 600;
    font-size: 1.2rem;
    color: var(--text-color);
    display: block;
    text-align: center;
    line-height: 30px;
}

/* Question Container */
.question-container {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
}

.question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--border-color);
}

.question-number {
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--primary-color);
}

.question-category {
    background: var(--secondary-color);
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: uppercase;
}

.question-text {
    font-size: 1.2rem;
    font-weight: 500;
    margin-bottom: 25px;
    line-height: 1.8;
    color: var(--text-color);
}

.question-image-container {
    text-align: center;
    margin: 25px 0;
    display: none;
}

.question-image-container.visible {
    display: block;
}

.question-image-container img {
    max-width: 100%;
    max-height: 400px;
    border-radius: 8px;
    box-shadow: var(--shadow);
}

/* Answers */
.answers {
    margin: 25px 0;
}

.answer-option {
    background: var(--bg-color);
    padding: 15px 20px;
    margin-bottom: 12px;
    border-radius: 8px;
    border: 2px solid transparent;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    font-size: 1rem;
}

.answer-option:hover {
    background: #e5e7eb;
    border-color: var(--secondary-color);
}

.answer-option.selected {
    background: #dbeafe;
    border-color: var(--primary-color);
}

.answer-option.correct {
    background: #d1fae5;
    border-color: var(--success-color);
}

.answer-option.incorrect {
    background: #fee2e2;
    border-color: var(--error-color);
}

.answer-option.disabled {
    cursor: not-allowed;
    opacity: 0.7;
}

.answer-id {
    font-weight: 700;
    margin-right: 12px;
    min-width: 25px;
    color: var(--primary-color);
}

.answer-text {
    flex: 1;
}

/* Feedback */
.feedback {
    margin: 20px 0;
    padding: 15px 20px;
    border-radius: 8px;
    font-weight: 500;
    display: none;
}

.feedback.visible {
    display: block;
}

.feedback.success {
    background: #d1fae5;
    color: #065f46;
    border-left: 4px solid var(--success-color);
}

.feedback.error {
    background: #fee2e2;
    color: #991b1b;
    border-left: 4px solid var(--error-color);
}

/* Question Actions */
.question-actions {
    display: flex;
    gap: 15px;
    margin-top: 25px;
    flex-wrap: wrap;
}

.question-actions .btn {
    flex: 1;
    min-width: 150px;
}

/* Exam Mode Specific */
.exam-header {
    background: var(--card-bg);
    padding: 15px 20px;
    border-radius: 12px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

.exam-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    font-size: 1.1rem;
}

.exam-timer {
    color: var(--primary-color);
    font-size: 1.3rem;
}

/* Question Navigator */
.question-navigator {
    background: var(--card-bg);
    padding: 20px;
    border-radius: 12px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

.navigator-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(45px, 1fr));
    gap: 8px;
}

.navigator-item {
    width: 45px;
    height: 45px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
    border: 2px solid var(--border-color);
    background: var(--bg-color);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.navigator-item:hover {
    background: #e5e7eb;
    border-color: var(--secondary-color);
}

.navigator-item.current {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.navigator-item.answered {
    background: #dbeafe;
    border-color: var(--secondary-color);
}

/* Exam Actions */
.exam-actions {
    display: flex;
    gap: 15px;
    margin-top: 25px;
    flex-wrap: wrap;
}

.exam-actions .btn {
    flex: 1;
    min-width: 120px;
}

/* Result Screen */
.result-container {
    background: var(--card-bg);
    padding: 40px;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
}

.result-header {
    text-align: center;
    padding: 30px;
    border-radius: 12px;
    margin-bottom: 30px;
}

.result-header.passed {
    background: linear-gradient(135deg, #d1fae5, #a7f3d0);
}

.result-header.failed {
    background: linear-gradient(135deg, #fee2e2, #fecaca);
}

.result-icon {
    font-size: 4rem;
    margin-bottom: 15px;
}

.result-header h2 {
    font-size: 2rem;
    margin-bottom: 10px;
}

.result-score {
    font-size: 1.5rem;
    font-weight: 600;
}

.result-details {
    margin-bottom: 30px;
}

.result-details p {
    margin-bottom: 20px;
    text-align: center;
    color: var(--neutral-color);
}

.wrong-answers {
    margin-top: 20px;
}

.wrong-answer-item {
    background: var(--bg-color);
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 10px;
    border-left: 4px solid var(--error-color);
}

.wrong-answer-item strong {
    color: var(--primary-color);
}

.result-actions {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

.result-actions .btn {
    flex: 1;
    min-width: 150px;
}

/* Statistics */
.statistics-container {
    background: var(--card-bg);
    padding: 40px;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
}

.statistics-container h2 {
    text-align: center;
    margin-bottom: 30px;
}

.stats-overview {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 40px;
}

.stat-card {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    padding: 25px;
    border-radius: 12px;
    text-align: center;
    color: white;
}

.stat-label {
    font-size: 0.9rem;
    opacity: 0.9;
    margin-bottom: 10px;
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 700;
}

.difficult-questions {
    margin-bottom: 30px;
}

.difficult-questions h3 {
    margin-bottom: 10px;
    color: var(--primary-color);
}

.section-description {
    color: var(--neutral-color);
    font-size: 0.9rem;
    margin-bottom: 20px;
}

.difficult-question-item {
    background: var(--bg-color);
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 10px;
    border-left: 4px solid var(--warning-color);
}

.difficulty-stats {
    display: flex;
    gap: 15px;
    margin-top: 8px;
    font-size: 0.9rem;
    color: var(--neutral-color);
}

.statistics-actions {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

.statistics-actions .btn {
    flex: 1;
    min-width: 150px;
}

/* Category Statistics Table */
.category-stats-section {
    margin-bottom: 30px;
}

.category-stats-section h3 {
    margin-bottom: 10px;
    color: var(--primary-color);
}

.category-stats-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.95rem;
}

.category-stats-table thead tr {
    background: var(--primary-color);
    color: white;
}

.category-stats-table th,
.category-stats-table td {
    padding: 10px 12px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.category-stats-table tbody tr:hover {
    background: var(--bg-color);
}

.rate-good { color: #16a34a; font-weight: 600; }
.rate-ok   { color: var(--warning-color); font-weight: 600; }
.rate-bad  { color: var(--error-color); font-weight: 600; }

.perfect-badge {
    background: #fef9c3;
    color: #854d0e;
    padding: 2px 8px;
    border-radius: 12px;
    font-weight: 700;
    font-size: 0.9rem;
}

.zero-badge {
    color: var(--neutral-color);
}

/* Learning Result Screen */
.result-category-label {
    margin-top: 8px;
    font-size: 1rem;
    opacity: 0.8;
}

.result-header:not(.passed):not(.failed) {
    background: linear-gradient(135deg, #dbeafe, #bfdbfe);
}

/* Authentication Forms */
.auth-container {
    max-width: 500px;
    margin: 0 auto;
}

.auth-form {
    background: var(--card-bg);
    padding: 40px;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    display: none;
}

.auth-form.active {
    display: block;
}

.auth-form h2 {
    text-align: center;
    margin-bottom: 30px;
    color: var(--text-color);
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-color);
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.error-message {
    color: var(--error-color);
    font-size: 0.9rem;
    margin: 15px 0;
    min-height: 20px;
}

.auth-switch {
    text-align: center;
    margin-top: 20px;
    color: var(--neutral-color);
}

.auth-switch a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
}

.auth-switch a:hover {
    text-decoration: underline;
}

.auth-form .btn {
    width: 100%;
    margin-top: 10px;
}

/* User Info in Header */
.user-info {
    background: var(--card-bg);
    padding: 15px 20px;
    border-radius: 12px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-color);
}

.user-info .username {
    font-weight: 600;
    font-size: 1.1rem;
}

.user-info .logout-btn {
    padding: 8px 16px;
    font-size: 0.9rem;
}

/* Admin Dashboard */
.users-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--card-bg);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: var(--shadow);
    margin-bottom: 20px;
}

.users-table thead {
    background: var(--primary-color);
    color: white;
}

.users-table th,
.users-table td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.users-table tbody tr:hover {
    background: var(--bg-color);
}

.users-table tbody tr:last-child td {
    border-bottom: none;
}

.loading {
    text-align: center;
    padding: 40px;
    font-size: 1.2rem;
    color: var(--neutral-color);
}

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 1.8rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .mode-cards {
        grid-template-columns: 1fr;
    }

    .category-buttons {
        grid-template-columns: 1fr;
    }

    .question-container {
        padding: 20px;
    }

    .question-text {
        font-size: 1.1rem;
    }

    .stats-overview {
        grid-template-columns: 1fr 1fr;
    }

    .stat-value {
        font-size: 2rem;
    }

    .navigator-grid {
        grid-template-columns: repeat(auto-fill, minmax(40px, 1fr));
    }

    .navigator-item {
        width: 40px;
        height: 40px;
        font-size: 0.9rem;
    }

    .question-actions,
    .exam-actions,
    .result-actions,
    .statistics-actions {
        flex-direction: column;
    }

    .question-actions .btn,
    .exam-actions .btn,
    .result-actions .btn,
    .statistics-actions .btn {
        width: 100%;
        min-width: auto;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 10px;
    }

    .mode-selection,
    .category-selection,
    .question-container,
    .result-container,
    .statistics-container {
        padding: 20px;
    }

    .stats-overview {
        grid-template-columns: 1fr;
    }
}