/* Flashcard Styles */
.flashcard-section {
    padding: var(--spacing-lg) 0;
    min-height: 80vh;
}

.progress-container {
    margin-bottom: var(--spacing-lg);
}

.progress-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
    font-size: 0.9375rem;
    color: var(--text-secondary);
}

.progress-bar {
    height: 8px;
    background-color: var(--light-bg);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-color) 0%, #1e4a5f 100%);
    transition: width 0.3s ease;
}

.flashcard-container {
    max-width: 600px;
    margin: 0 auto var(--spacing-lg);
}

.flashcard {
    perspective: 1000px;
    height: 280px;
    cursor: pointer;
    margin-bottom: var(--spacing-md);
}

.flashcard-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.6s;
    transform-style: preserve-3d;
}

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

.flashcard-front,
.flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: var(--white);
    border-radius: 12px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
    padding: var(--spacing-lg);
}

.flashcard-back {
    transform: rotateY(180deg);
    background: linear-gradient(135deg, var(--accent-color) 0%, #1e4a5f 100%);
    color: var(--white);
}

.card-lang {
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

.card-text {
    font-size: 1.5rem;
    font-weight: 600;
    text-align: center;
    margin: 0;
}

.card-hint {
    margin-top: var(--spacing-md);
    font-size: 0.875rem;
    color: var(--text-secondary);
    opacity: 0.7;
}

.card-category {
    margin-top: var(--spacing-md);
    font-size: 0.9375rem;
    opacity: 0.9;
    padding: 0.25rem 0.75rem;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 20px;
}

.flashcard-controls {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    margin-bottom: var(--spacing-md);
}

.control-btn {
    padding: 0.75rem 1.5rem;
    background-color: var(--white);
    border: 2px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    color: var(--text-primary);
}

.control-btn:hover:not(:disabled) {
    border-color: var(--accent-color);
    color: var(--accent-color);
}

.control-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.flip-btn {
    background-color: var(--accent-color);
    color: var(--white);
    border-color: var(--accent-color);
}

.flip-btn:hover {
    background-color: #23516a;
    border-color: #23516a;
    color: var(--white);
}

.confidence-controls {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    margin-top: var(--spacing-md);
}

.confidence-btn {
    flex: 1;
    max-width: 250px;
    padding: 1rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

.need-practice {
    background-color: #ffc107;
    color: #000;
}

.need-practice:hover {
    background-color: #e0a800;
}

.got-it {
    background-color: #28a745;
    color: var(--white);
}

.got-it:hover {
    background-color: #218838;
}

.flashcard-sidebar {
    max-width: 600px;
    margin: 0 auto;
}

.filter-section,
.search-section {
    margin-bottom: var(--spacing-md);
}

.filter-section h3 {
    font-size: 1.125rem;
    margin-bottom: var(--spacing-sm);
}

.filter-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.filter-btn {
    padding: 0.5rem 1rem;
    background-color: var(--white);
    border: 2px solid var(--border-color);
    border-radius: 20px;
    font-size: 0.875rem;
    cursor: pointer;
    transition: all 0.2s ease;
}

.filter-btn:hover {
    border-color: var(--accent-color);
}

.filter-btn.active {
    background-color: var(--accent-color);
    color: var(--white);
    border-color: var(--accent-color);
}

.search-input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
}

/* Audio pronunciation button */
.audio-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    margin-top: var(--spacing-sm);
    padding: 0.5rem;
    transition: transform 0.2s ease;
}

.audio-btn:hover {
    transform: scale(1.2);
}

.audio-btn:active {
    transform: scale(0.95);
}

/* Leitner Boxes */
.leitner-section {
    margin-bottom: var(--spacing-xl);
}

.box-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: var(--spacing-md);
}

.box-card {
    background: var(--white);
    border-radius: 8px;
    padding: var(--spacing-md);
    cursor: pointer;
    transition: all 0.2s ease;
    border: 2px solid #e0e0e0;
}

.box-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.box-card.box1 {
    border-left: 4px solid #ff6b6b;
}

.box-card.box1:hover {
    border-color: #ff6b6b;
    background: #fff5f5;
}

.box-card.box2 {
    border-left: 4px solid #ffd93d;
}

.box-card.box2:hover {
    border-color: #ffd93d;
    background: #fffef5;
}

.box-card.box3 {
    border-left: 4px solid #6bcf7f;
}

.box-card.box3:hover {
    border-color: #6bcf7f;
    background: #f5fff7;
}

.box-card.mastered {
    border-left: 4px solid #9b59b6;
}

.box-card.mastered:hover {
    border-color: #9b59b6;
    background: #f9f5ff;
}

.box-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: var(--spacing-sm);
}

.box-number {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--accent-color);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1rem;
}

.box-card.box1 .box-number {
    background: #ff6b6b;
}

.box-card.box2 .box-number {
    background: #ffd93d;
    color: #333;
}

.box-card.box3 .box-number {
    background: #6bcf7f;
}

.box-card.mastered .box-number {
    background: #9b59b6;
}

.box-name {
    font-weight: 600;
    font-size: 1rem;
    color: var(--text-primary);
}

.box-count {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--accent-color);
    margin-bottom: 0.25rem;
}

.box-interval {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Quick Actions */
.quick-actions {
    margin-bottom: var(--spacing-xl);
}

.action-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-md);
}

.action-btn {
    background: var(--white);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: var(--spacing-md);
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.action-btn:hover {
    border-color: var(--accent-color);
    background: rgba(43, 104, 131, 0.05);
}

.action-label {
    font-weight: 600;
    color: var(--text-primary);
}

.action-count {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-color);
}

/* Topics */
.topic-section {
    margin-bottom: var(--spacing-xl);
}

.topic-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-sm);
}

.topic-btn {
    background: var(--white);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: var(--spacing-md);
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    justify-content: space-between;
    align-items: center;
    text-align: left;
}

.topic-btn:hover {
    border-color: var(--accent-color);
    background: var(--light-bg);
}

.topic-name {
    font-weight: 500;
    color: var(--text-primary);
}

.topic-count {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Session Summary */
.summary-card {
    background: var(--white);
    border-radius: 8px;
    padding: var(--spacing-xl);
    max-width: 700px;
    margin: 0 auto;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.summary-title {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
    text-align: center;
    font-weight: 600;
}

.summary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.summary-stat {
    padding: var(--spacing-md);
    background: var(--light-bg);
    border-radius: 8px;
    text-align: center;
}

.summary-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.summary-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--accent-color);
}

.summary-value.success {
    color: #28a745;
}

.summary-value.warning {
    color: #f39c12;
}

.summary-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
}

.btn-primary {
    background: var(--accent-color);
    color: white;
    border: none;
    padding: 0.75rem 2rem;
    border-radius: 4px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s ease;
}

.btn-primary:hover {
    background: #23516a;
}

.btn-secondary {
    background: white;
    color: var(--accent-color);
    border: 2px solid var(--accent-color);
    padding: 0.75rem 2rem;
    border-radius: 4px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
}

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

/* Box Badge */
.box-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
    color: white;
    margin-right: var(--spacing-sm);
}

.back-to-deck-btn {
    background: none;
    border: 2px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: 4px;
    font-size: 0.875rem;
    cursor: pointer;
    transition: all 0.2s ease;
    color: var(--text-primary);
    font-weight: 500;
}

.back-to-deck-btn:hover {
    border-color: var(--accent-color);
    color: var(--accent-color);
    background: rgba(43, 104, 131, 0.1);
}