:root {
    --primary-color: #00D4FF;
    --primary-dark: #00A8CC;
    --primary-glow: rgba(0, 212, 255, 0.5);
    --secondary-color: #6c757d;
    --success-color: #00FF88;
    --danger-color: #FF4757;
    --warning-color: #FFD93D;
    --bg-color: #0a0a1a;
    --bg-secondary: #12122a;
    --card-bg: rgba(18, 18, 42, 0.95);
    --text-color: #ffffff;
    --text-light: #a0a0c0;
    --border-color: rgba(0, 212, 255, 0.3);
    --shadow: 0 4px 20px rgba(0, 212, 255, 0.15);
    --shadow-glow: 0 0 30px rgba(0, 212, 255, 0.3);
    --radius: 16px;
    --gradient-primary: linear-gradient(135deg, #00D4FF 0%, #00FF88 100%);
    --gradient-dark: linear-gradient(180deg, #0a0a1a 0%, #12122a 100%);
}

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

body {
    font-family: 'SF Pro Display', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg-color);
    background-image: 
        radial-gradient(ellipse at top, rgba(0, 212, 255, 0.1) 0%, transparent 50%),
        radial-gradient(ellipse at bottom, rgba(0, 255, 136, 0.05) 0%, transparent 50%),
        var(--gradient-dark);
    color: var(--text-color);
    line-height: 1.6;
    min-height: 100vh;
}

#app {
    max-width: 100%;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.header {
    background: rgba(10, 10, 26, 0.9);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    padding: 15px 20px;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow);
}

.header h1 {
    font-size: 1.5rem;
    text-align: center;
    margin-bottom: 15px;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 700;
    letter-spacing: 2px;
    text-shadow: 0 0 30px var(--primary-glow);
}

.nav-tabs {
    display: flex;
    gap: 8px;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
}

.nav-tabs::-webkit-scrollbar {
    display: none;
}

.tab-btn {
    flex: 1;
    min-width: 80px;
    padding: 10px 15px;
    border: 1px solid var(--border-color);
    background: transparent;
    color: var(--text-light);
    border-radius: 12px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
    position: relative;
    overflow: hidden;
}

.tab-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(0, 212, 255, 0.2), transparent);
    transition: left 0.5s ease;
}

.tab-btn:hover::before {
    left: 100%;
}

.tab-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    box-shadow: 0 0 20px rgba(0, 212, 255, 0.2);
}

.tab-btn.active {
    background: var(--gradient-primary);
    border-color: transparent;
    color: #0a0a1a;
    font-weight: 600;
    box-shadow: var(--shadow-glow);
}

.main-content {
    flex: 1;
    padding: 15px;
    padding-bottom: 30px;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
    position: relative;
    overflow: hidden;
}

.btn::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.3s ease, height 0.3s ease;
}

.btn:active::after {
    width: 200px;
    height: 200px;
}

.btn-primary {
    background: var(--gradient-primary);
    color: #0a0a1a;
    box-shadow: 0 4px 15px rgba(0, 212, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(0, 212, 255, 0.4);
}

.btn-large {
    width: 100%;
    padding: 15px 30px;
    font-size: 1.1rem;
    font-weight: 600;
}

.btn-secondary {
    background: rgba(0, 212, 255, 0.1);
    color: var(--primary-color);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: rgba(0, 212, 255, 0.2);
    border-color: var(--primary-color);
}

.btn-success {
    background: linear-gradient(135deg, #00FF88 0%, #00D4FF 100%);
    color: #0a0a1a;
    box-shadow: 0 4px 15px rgba(0, 255, 136, 0.3);
}

.btn-success:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(0, 255, 136, 0.4);
}

.btn-danger {
    background: linear-gradient(135deg, #FF4757 0%, #FF6B7A 100%);
    color: white;
    box-shadow: 0 4px 15px rgba(255, 71, 87, 0.3);
}

.btn-danger:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(255, 71, 87, 0.4);
}

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

.hidden {
    display: none !important;
}

.upload-area {
    background: var(--card-bg);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius);
    padding: 60px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.upload-area::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: conic-gradient(from 0deg, transparent, var(--primary-color), transparent 30%);
    animation: rotate 4s linear infinite;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.upload-area:hover::before {
    opacity: 0.3;
}

@keyframes rotate {
    100% { transform: rotate(360deg); }
}

.upload-area:hover {
    border-color: var(--primary-color);
    background: rgba(0, 212, 255, 0.05);
    box-shadow: var(--shadow-glow);
}

.upload-placeholder .icon {
    font-size: 4rem;
    display: block;
    margin-bottom: 15px;
    filter: drop-shadow(0 0 20px var(--primary-glow));
}

.upload-placeholder p {
    color: var(--text-light);
    font-size: 1rem;
}

.capture-btn {
    margin-top: 15px;
    margin-right: 10px;
    padding: 12px 30px;
    font-size: 1rem;
    font-weight: 600;
    color: #fff;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border: none;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 20px rgba(0, 212, 255, 0.4);
}

.capture-btn:active {
    transform: scale(0.95);
    box-shadow: 0 2px 10px rgba(0, 212, 255, 0.3);
}

.capture-btn-secondary {
    background: rgba(0, 212, 255, 0.2);
    border: 1px solid var(--primary-color);
    box-shadow: none;
}

.capture-btn-secondary:active {
    background: rgba(0, 212, 255, 0.3);
}

.upload-hint {
    margin-top: 15px;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.preview-container {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 15px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.subject-bar {
    margin-bottom: 15px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border-color);
}

.subject-bar label {
    display: block;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 1px;
    font-size: 0.85rem;
}

.subject-pills {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.subject-pill {
    padding: 8px 16px;
    border: 1px solid var(--border-color);
    background: transparent;
    border-radius: 20px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.3s ease;
    color: var(--text-light);
}

.subject-pill:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    box-shadow: 0 0 15px rgba(0, 212, 255, 0.2);
}

.subject-pill.active {
    background: var(--gradient-primary);
    border-color: transparent;
    color: #0a0a1a;
    box-shadow: var(--shadow-glow);
}

.image-wrapper {
    position: relative;
    width: 100%;
    overflow: hidden;
    border-radius: 12px;
    background: linear-gradient(135deg, #1a1a2e 0%, #0a0a1a 100%);
    border: 1px solid var(--border-color);
}

.image-wrapper img {
    width: 100%;
    display: block;
}

.crop-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    touch-action: none;
}

.crop-box {
    position: absolute;
    border: 2px solid var(--primary-color);
    background: transparent;
    cursor: move;
    box-shadow: 0 0 0 9999px rgba(0, 0, 0, 0.7), 0 0 20px var(--primary-glow);
    touch-action: none;
}

.crop-box::before,
.crop-box::after {
    content: '';
    position: absolute;
    left: 0;
    right: 0;
    height: 1px;
    background: rgba(0, 212, 255, 0.5);
}

.crop-box::before { top: 33.33%; }
.crop-box::after { top: 66.66%; }

.crop-box .grid-v1,
.crop-box .grid-v2 {
    position: absolute;
    top: 0;
    bottom: 0;
    width: 1px;
    background: rgba(0, 212, 255, 0.5);
}

.crop-box .grid-v1 { left: 33.33%; }
.crop-box .grid-v2 { left: 66.66%; }

.crop-handles {
    position: absolute;
    top: -8px;
    left: -8px;
    right: -8px;
    bottom: -8px;
}

.crop-handle {
    position: absolute;
    width: 16px;
    height: 16px;
    background: var(--primary-color);
    border: 2px solid white;
    border-radius: 50%;
    box-shadow: 0 0 10px var(--primary-glow);
}

.crop-handle.nw { top: 0; left: 0; cursor: nw-resize; }
.crop-handle.ne { top: 0; right: 0; cursor: ne-resize; }
.crop-handle.sw { bottom: 0; left: 0; cursor: sw-resize; }
.crop-handle.se { bottom: 0; right: 0; cursor: se-resize; }
.crop-handle.n { top: 0; left: 50%; transform: translateX(-50%); cursor: n-resize; }
.crop-handle.s { bottom: 0; left: 50%; transform: translateX(-50%); cursor: s-resize; }
.crop-handle.w { top: 50%; left: 0; transform: translateY(-50%); cursor: w-resize; }
.crop-handle.e { top: 50%; right: 0; transform: translateY(-50%); cursor: e-resize; }

.crop-controls {
    display: flex;
    gap: 10px;
    margin-top: 15px;
    justify-content: center;
}

.subject-select {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px;
    margin-top: 15px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.subject-select h3 {
    margin-bottom: 15px;
    color: var(--text-color);
}

.subject-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
}

.subject-btn {
    padding: 15px 10px;
    border: 1px solid var(--border-color);
    background: transparent;
    border-radius: 12px;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all 0.3s ease;
    color: var(--text-light);
}

.subject-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    box-shadow: 0 0 15px rgba(0, 212, 255, 0.2);
}

.subject-btn.active {
    background: var(--gradient-primary);
    border-color: transparent;
    color: #0a0a1a;
    box-shadow: var(--shadow-glow);
}

.ocr-result, .ai-analysis {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px;
    margin-top: 15px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.ocr-result h3, .ai-analysis h3 {
    margin-bottom: 15px;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 10px;
}

.ocr-result h3::before, .ai-analysis h3::before {
    content: '';
    width: 4px;
    height: 20px;
    background: var(--gradient-primary);
    border-radius: 2px;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-color);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px 15px;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background: rgba(0, 0, 0, 0.3);
    color: var(--text-color);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 20px rgba(0, 212, 255, 0.2);
}

.form-group textarea {
    resize: vertical;
    min-height: 80px;
}

.form-group select option {
    background: var(--bg-secondary);
    color: var(--text-color);
}

.action-buttons {
    display: flex;
    gap: 10px;
    justify-content: center;
    margin-top: 20px;
}

.analysis-content {
    background: rgba(0, 0, 0, 0.3);
    padding: 15px;
    border-radius: 12px;
    margin-bottom: 15px;
    border: 1px solid rgba(0, 212, 255, 0.1);
}

.analysis-content h4 {
    color: var(--primary-color);
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.analysis-content h4::before {
    content: '▸';
    color: var(--primary-color);
}

.analysis-content p {
    margin-bottom: 10px;
    color: var(--text-color);
}

.analysis-content .answer {
    background: rgba(0, 255, 136, 0.1);
    padding: 12px;
    border-radius: 8px;
    border-left: 3px solid var(--success-color);
}

.analysis-content .explanation {
    background: rgba(0, 212, 255, 0.1);
    padding: 12px;
    border-radius: 8px;
    border-left: 3px solid var(--primary-color);
}

.practice-option {
    margin: 15px 0;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    color: var(--text-color);
}

.checkbox-label input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: var(--primary-color);
}

.practice-questions {
    margin-top: 15px;
    padding: 15px;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 12px;
    border: 1px solid rgba(255, 217, 61, 0.2);
}

.practice-questions h4 {
    margin-bottom: 15px;
    color: var(--warning-color);
}

.practice-item {
    background: rgba(255, 217, 61, 0.05);
    padding: 15px;
    border-radius: 10px;
    margin-bottom: 10px;
    border-left: 3px solid var(--warning-color);
}

.practice-item:last-child {
    margin-bottom: 0;
}

.list-container {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 15px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.filter-bar {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 15px;
}

.filter-bar select,
.filter-bar input {
    padding: 10px 15px;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    font-size: 0.9rem;
    flex: 1;
    min-width: 120px;
    background: rgba(0, 0, 0, 0.3);
    color: var(--text-color);
}

.filter-bar select:focus,
.filter-bar input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 15px rgba(0, 212, 255, 0.2);
}

.question-list {
    min-height: 200px;
}

.question-item {
    background: rgba(0, 0, 0, 0.3);
    border-radius: 12px;
    padding: 15px;
    margin-bottom: 10px;
    display: flex;
    gap: 12px;
    align-items: flex-start;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 1px solid transparent;
}

.question-item:hover {
    transform: translateX(5px);
    border-color: var(--border-color);
    box-shadow: var(--shadow);
}

.question-item .checkbox {
    width: 22px;
    height: 22px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    flex-shrink: 0;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.question-item .checkbox.checked {
    background: var(--gradient-primary);
    border-color: transparent;
    color: #0a0a1a;
    box-shadow: var(--shadow-glow);
}

.question-item .checkbox.checked::after {
    content: '✓';
    font-size: 14px;
    font-weight: bold;
}

.question-item .content {
    flex: 1;
    min-width: 0;
}

.question-item .subject-tag {
    display: inline-block;
    padding: 3px 12px;
    background: var(--gradient-primary);
    color: #0a0a1a;
    border-radius: 15px;
    font-size: 0.75rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.question-item .question-preview {
    font-size: 0.95rem;
    color: var(--text-color);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.question-item .meta {
    display: flex;
    gap: 15px;
    margin-top: 8px;
    font-size: 0.8rem;
    color: var(--text-light);
}

.question-thumb {
    width: 60px;
    height: 60px;
    object-fit: cover;
    border-radius: 8px;
    float: left;
    margin-right: 12px;
    margin-bottom: 8px;
    border: 1px solid var(--border-color);
}

.question-image-preview {
    margin-bottom: 15px;
    text-align: center;
}

.question-image-preview img {
    max-width: 100%;
    max-height: 200px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.question-item .status {
    padding: 2px 10px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 500;
}

.status.new {
    background: rgba(255, 71, 87, 0.2);
    color: var(--danger-color);
}

.status.reviewing {
    background: rgba(255, 217, 61, 0.2);
    color: var(--warning-color);
}

.status.mastered {
    background: rgba(0, 255, 136, 0.2);
    color: var(--success-color);
}

.list-actions {
    display: flex;
    gap: 10px;
    margin-top: 15px;
    justify-content: center;
}

.empty-state {
    text-align: center;
    padding: 40px 20px;
    color: var(--text-light);
}

.empty-state .icon {
    font-size: 4rem;
    margin-bottom: 15px;
    filter: drop-shadow(0 0 20px var(--primary-glow));
}

.review-container {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.review-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
}

.stat-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px 15px;
    text-align: center;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-primary);
}

.stat-value {
    display: block;
    font-size: 2rem;
    font-weight: bold;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-top: 5px;
}

.review-today, .review-calendar {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.review-today h3, .review-calendar h3 {
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.review-today h3::before, .review-calendar h3::before {
    content: '';
    width: 4px;
    height: 20px;
    background: var(--gradient-primary);
    border-radius: 2px;
}

.review-list {
    min-height: 100px;
}

.calendar {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 5px;
}

.calendar-day {
    aspect-ratio: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 10px;
    font-size: 0.85rem;
    background: rgba(0, 0, 0, 0.3);
    color: var(--text-light);
}

.calendar-day.today {
    background: var(--gradient-primary);
    color: #0a0a1a;
    font-weight: bold;
    box-shadow: var(--shadow-glow);
}

.calendar-day.has-review {
    background: rgba(0, 212, 255, 0.2);
    color: var(--primary-color);
}

.calendar-day.header {
    background: transparent;
    font-weight: 600;
    color: var(--primary-color);
}

.settings-container {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.settings-group {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.settings-group h3 {
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 10px;
}

.settings-group h3::before {
    content: '';
    width: 4px;
    height: 20px;
    background: var(--gradient-primary);
    border-radius: 2px;
}

.settings-group .form-group {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 10px;
}

.settings-group .form-group label {
    margin-bottom: 0;
}

.settings-group input[type="text"],
.settings-group input[type="password"],
.settings-group input[type="number"],
.settings-group select {
    max-width: 200px;
}

.settings-group button {
    margin-right: 10px;
    margin-bottom: 10px;
}

.hint {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-top: 10px;
}

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

.hint a:hover {
    text-decoration: underline;
}

.ocr-tips {
    margin-top: 15px;
    padding: 15px;
    background: rgba(255, 217, 61, 0.1);
    border-radius: 10px;
    border-left: 3px solid var(--warning-color);
}

.ocr-tips p {
    margin-bottom: 8px;
}

.ocr-tips ul {
    margin: 0;
    padding-left: 20px;
}

.ocr-tips li {
    margin-bottom: 5px;
    font-size: 0.9rem;
    color: var(--text-light);
}

.switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 28px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    transition: 0.4s;
    border-radius: 28px;
    border: 1px solid var(--border-color);
}

.slider:before {
    position: absolute;
    content: "";
    height: 20px;
    width: 20px;
    left: 3px;
    bottom: 3px;
    background: var(--text-light);
    transition: 0.4s;
    border-radius: 50%;
}

input:checked + .slider {
    background: var(--gradient-primary);
    border-color: transparent;
    box-shadow: var(--shadow-glow);
}

input:checked + .slider:before {
    transform: translateX(22px);
    background: white;
}

.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 20px;
}

.modal-content {
    background: var(--card-bg);
    border-radius: var(--radius);
    width: 100%;
    max-width: 500px;
    max-height: 90vh;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-glow);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 1.1rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-light);
    transition: color 0.3s ease;
}

.close-btn:hover {
    color: var(--danger-color);
}

.modal-body {
    padding: 20px;
    overflow-y: auto;
    flex: 1;
}

.modal-footer {
    display: flex;
    gap: 10px;
    padding: 15px 20px;
    border-top: 1px solid var(--border-color);
    justify-content: flex-end;
}

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.9);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 2000;
}

.loading-spinner {
    width: 60px;
    height: 60px;
    border: 3px solid rgba(0, 212, 255, 0.2);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    box-shadow: 0 0 30px var(--primary-glow);
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-overlay p {
    color: var(--primary-color);
    margin-top: 20px;
    font-size: 1rem;
    letter-spacing: 1px;
}

.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--gradient-primary);
    color: #0a0a1a;
    padding: 12px 24px;
    border-radius: 25px;
    font-size: 0.95rem;
    font-weight: 500;
    z-index: 3000;
    animation: fadeInUp 0.3s ease;
    box-shadow: var(--shadow-glow);
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateX(-50%) translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateX(-50%) translateY(0);
    }
}

@media print {
    .header, .nav-tabs, .filter-bar, .list-actions, .modal-footer {
        display: none !important;
    }
    
    .main-content {
        padding: 0;
    }
    
    .question-item {
        break-inside: avoid;
        page-break-inside: avoid;
    }
    
    body {
        background: white;
        color: black;
    }
}

@media (min-width: 768px) {
    .header h1 {
        font-size: 1.8rem;
    }
    
    .subject-grid {
        grid-template-columns: repeat(5, 1fr);
    }
    
    .review-stats {
        max-width: 400px;
    }
}