/* Common styles for all guide pages */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    font-size: 18px;
    background: linear-gradient(120deg, #e0e7ff 0%, #f8fafc 100%);
    color: #222;
    min-height: 100vh;
    letter-spacing: 0.01em;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 32px 20px;
}

.header {
    text-align: center;
    margin-bottom: 36px;
    color: #222;
}

.header h1 {
    font-size: 2.4rem;
    margin-bottom: 12px;
    text-shadow: 0 2px 8px rgba(102,126,234,0.10);
    font-weight: 700;
    letter-spacing: 0.02em;
}

.header p {
    font-size: 1.2rem;
    opacity: 0.85;
}

.guide-section {
    background: linear-gradient(120deg, #fff 60%, #f3f8ff 100%);
    margin-bottom: 32px;
    border-radius: 22px;
    padding: 32px 28px;
    box-shadow: 0 8px 32px rgba(102,126,234,0.10);
    transition: transform 0.3s cubic-bezier(.4,0,.2,1), box-shadow 0.3s;
}

.guide-section:hover {
    transform: translateY(-4px) scale(1.01);
    box-shadow: 0 16px 40px rgba(102,126,234,0.18);
}

.section-title {
    font-size: 1.6rem;
    color: #4f46e5;
    margin-bottom: 22px;
    display: flex;
    align-items: center;
    gap: 14px;
    font-weight: 700;
}

.section-title .icon {
    font-size: 2rem;
}

/* Navigation Menu Styles */
.guide-nav {
    background: linear-gradient(120deg, #f8fafc 60%, #e0e7ff 100%);
    backdrop-filter: blur(12px);
    border-radius: 18px;
    padding: 28px 24px;
    margin-bottom: 38px;
    box-shadow: 0 8px 32px rgba(102,126,234,0.10);
    border: 1.5px solid #e0e7ff;
}

.nav-title {
    font-size: 1.4rem;
    color: #4f46e5;
    margin-bottom: 18px;
    font-weight: 700;
    text-align: center;
    letter-spacing: 0.01em;
}

.nav-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 18px;
}

.nav-item {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 18px 22px;
    background: linear-gradient(120deg, #f3f8ff 60%, #fff 100%);
    border: 2.5px solid transparent;
    border-radius: 14px;
    text-decoration: none;
    color: #222;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all 0.25s cubic-bezier(.4,0,.2,1);
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(102,126,234,0.07);
}

.nav-item:hover, .nav-item.active {
    border-color: #6366f1;
    background: linear-gradient(120deg, #6366f1 60%, #818cf8 100%);
    color: #fff;
    box-shadow: 0 6px 18px rgba(102,126,234,0.18);
    transform: translateY(-2px) scale(1.03);
}

.nav-icon {
    font-size: 1.4rem;
    min-width: 28px;
}

/* Feature list styles */
.feature-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 22px;
    margin-top: 18px;
}

.feature-item {
    background: linear-gradient(120deg, #f8fafc 60%, #e0e7ff 100%);
    padding: 22px 18px;
    border-radius: 14px;
    border-left: 5px solid #6366f1;
    box-shadow: 0 2px 10px rgba(102,126,234,0.07);
}

.feature-item h4 {
    color: #4f46e5;
    margin-bottom: 10px;
    font-size: 1.15rem;
    font-weight: 700;
}

.feature-item p {
    font-size: 1rem;
    line-height: 1.5;
    color: #374151;
}

/* Tip box styles */
.tip-box {
    background: linear-gradient(120deg, #fef9c3 60%, #f3e8ff 100%);
    border: 1.5px solid #fde68a;
    border-radius: 12px;
    padding: 16px 18px;
    margin: 16px 0;
    font-size: 1rem;
    box-shadow: 0 2px 8px rgba(253,230,138,0.10);
}

.tip-box .tip-icon {
    color: #b45309;
    font-size: 1.2rem;
    margin-right: 10px;
    vertical-align: middle;
}

/* Animation utilities */
.fade-in {
    animation: fadeIn 0.6s ease;
}

.slide-in {
    animation: slideIn 0.5s ease;
}

.pulse {
    animation: pulse 2s infinite;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(15px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes slideIn {
    from { transform: translateX(-100%); }
    to { transform: translateX(0); }
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.03); }
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-8px); }
    60% { transform: translateY(-4px); }
}

/* Home page specific styles */
.home-header {
    padding: 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.profile-avatar {
    width: 35px;
    height: 35px;
    border-radius: 50%;
    background: linear-gradient(45deg, #667eea, #764ba2);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    font-size: 0.9rem;
}

.home-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 30px 15px;
    text-align: center;
}

.main-title {
    font-size: 1.6rem;
    font-weight: bold;
    color: #2c3e50;
    margin-bottom: 15px;
}

.subtitle {
    font-size: 1rem;
    color: #6c757d;
    margin-bottom: 25px;
}

.action-buttons {
    position: absolute;
    bottom: 100px;
    left: 15px;
    right: 15px;
    display: flex;
    gap: 12px;
}

.action-button {
    flex: 1;
    background: rgba(255, 255, 255, 0.9);
    border-radius: 10px;
    padding: 15px;
    text-align: center;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    transition: all 0.3s ease;
    cursor: pointer;
}

.action-button h4 {
    color: #667eea;
    margin-bottom: 6px;
    font-size: 0.9rem;
}

.action-button .value {
    font-size: 1.5rem;
    font-weight: bold;
    color: #2c3e50;
}

.action-button:hover {
    transform: scale(1.03);
}

.bottom-nav {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 70px;
    background: rgba(255, 255, 255, 0.95);
    display: flex;
    align-items: center;
    justify-content: space-around;
    border-top: 1px solid #e9ecef;
}

.nav-icon {
    font-size: 1.3rem;
    color: #6c757d;
}

/* Quiz page specific styles */
.question-area {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 25px 15px;
    text-align: center;
    background: linear-gradient(135deg, #f8f9fa 0%, #ffffff 100%);
}

.question-text {
    font-size: 1.8rem;
    font-weight: 700;
    color: #2c3e50;
    margin-bottom: 6px;
    text-shadow: 0 1px 2px rgba(0,0,0,0.1);
}

.pinyin-text {
    font-size: 1rem;
    color: #6c757d;
    margin-bottom: 20px;
    font-style: italic;
    font-weight: 500;
}

.example-sentence {
    background: linear-gradient(135deg, #e3f2fd 0%, #f3e5f5 100%);
    padding: 15px;
    border-radius: 10px;
    margin-bottom: 15px;
    font-style: italic;
    box-shadow: 0 2px 6px rgba(0,0,0,0.08);
    border: 1px solid rgba(102, 126, 234, 0.15);
    font-size: 0.9rem;
}

.options-container {
    position: absolute;
    bottom: 75px;
    left: 12px;
    right: 12px;
}

.option-button {
    width: 100%;
    padding: 12px 15px;
    margin-bottom: 6px;
    border: 2px solid #e9ecef;
    border-radius: 10px;
    background: linear-gradient(135deg, #ffffff 0%, #f8f9fa 100%);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    font-size: 0.9rem;
    font-weight: 500;
    color: #495057;
    box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}

.option-button:hover {
    border-color: #667eea;
    background: linear-gradient(135deg, #f0f4ff 0%, #e8f2ff 100%);
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(102, 126, 234, 0.15);
}

.option-button.correct {
    border-color: #28a745;
    background: linear-gradient(135deg, #d4edda 0%, #c3e6cb 100%);
    color: #155724;
}

.option-button.wrong {
    border-color: #dc3545;
    background: linear-gradient(135deg, #f8d7da 0%, #f5c6cb 100%);
    color: #721c24;
}

.bottom-bar {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 70px;
    background: linear-gradient(135deg, #ffffff 0%, #f8f9fa 100%);
    display: flex;
    align-items: center;
    justify-content: space-around;
    border-top: 1px solid #e9ecef;
    backdrop-filter: blur(10px);
}

.bottom-button {
    padding: 10px;
    border: none;
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    font-size: 1.2rem;
    cursor: pointer;
    border-radius: 50%;
    width: 42px;
    height: 42px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}

.bottom-button:hover {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 3px 8px rgba(102, 126, 234, 0.25);
}

.progress-bar {
    position: absolute;
    bottom: 0;
    left: 0;
    height: 3px;
    background: linear-gradient(90deg, #667eea 0%, #764ba2 100%);
    transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    border-radius: 0 0 24px 24px;
}

/* Enhanced phone mockup */
.phone-mockup::before {
    content: '';
    position: absolute;
    top: -2px;
    left: 50%;
    transform: translateX(-50%);
    width: 50px;
    height: 2px;
    background: #444;
    border-radius: 2px;
    box-shadow: inset 0 1px 1px rgba(0,0,0,0.4);
}

.phone-mockup::after {
    content: '';
    position: absolute;
    bottom: 6px;
    left: 50%;
    transform: translateX(-50%);
    width: 35px;
    height: 3px;
    background: #333;
    border-radius: 2px;
}

.phone-mockup:hover {
    transform: translateY(-4px) scale(1.02);
    box-shadow: 0 20px 48px rgba(0,0,0,0.28);
}

.phone-screen::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 30% 30%, rgba(255,255,255,0.08) 0%, transparent 70%);
    pointer-events: none;
    z-index: 1;
}

/* Gesture and swipe animations */
.gesture-arrow {
    font-size: 2.5rem;
    margin-bottom: 8px;
    color: #667eea;
    animation: bounce 2s infinite;
}

.swipe-demo {
    position: relative;
    width: 100%;
    height: 180px;
    background: rgba(102, 126, 234, 0.1);
    border-radius: 12px;
    margin: 15px 0;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.swipe-indicator {
    position: absolute;
    width: 45px;
    height: 45px;
    background: #667eea;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.3rem;
}

/* Step indicators and demo controls */
.step-indicator {
    display: flex;
    justify-content: center;
    gap: 8px;
    margin: 15px 0;
}

.step-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #ddd;
    transition: background 0.3s ease;
}

.step-dot.active {
    background: #667eea;
}

.step-dot.completed {
    background: #4caf50;
}

.demo-controls {
    display: flex;
    gap: 8px;
    justify-content: center;
    margin-top: 15px;
    flex-wrap: wrap;
}

.demo-button {
    padding: 8px 16px;
    border: 2px solid #667eea;
    background: white;
    color: #667eea;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
    font-size: 0.85rem;
}

.demo-button:hover {
    background: #667eea;
    color: white;
}

.demo-button.active {
    background: #667eea;
    color: white;
}

/* FAQ Styles */
.faq-section {
    background: linear-gradient(120deg, #f3e8ff 60%, #e0e7ff 100%);
    border-radius: 18px;
    padding: 32px 28px;
    margin-top: 38px;
    border: 1.5px solid #e0e7ff;
    box-shadow: 0 8px 32px rgba(102,126,234,0.10);
}

.faq-title {
    font-size: 1.7rem;
    color: #4f46e5;
    margin-bottom: 24px;
    display: flex;
    align-items: center;
    gap: 14px;
    font-weight: 700;
}

.faq-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 18px;
}

.faq-item {
    background: linear-gradient(120deg, #fff 60%, #f3f8ff 100%);
    border-radius: 14px;
    padding: 20px 18px;
    box-shadow: 0 2px 10px rgba(102,126,234,0.07);
    border-left: 5px solid #6366f1;
    cursor: pointer;
    transition: all 0.25s cubic-bezier(.4,0,.2,1);
}

.faq-item:hover, .faq-item.active {
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 6px 18px rgba(102,126,234,0.13);
    border-left: 5px solid #4f46e5;
}

.faq-question {
    font-weight: 700;
    color: #222;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.08rem;
}

.faq-answer {
    color: #444;
    font-size: 1rem;
    line-height: 1.6;
    display: none;
    padding-top: 10px;
    border-top: 1.5px solid #e0e7ff;
    margin-top: 10px;
}

.faq-item.active .faq-answer {
    display: block;
    animation: fadeIn 0.3s ease;
}

.faq-toggle {
    color: #6366f1;
    font-size: 1.3rem;
    margin-left: auto;
    transition: transform 0.3s;
}

.faq-item.active .faq-toggle {
    transform: rotate(180deg);
}

/* Quick Help Box */
.quick-help {
    background: linear-gradient(120deg, #e0ffe0 60%, #f0f8ff 100%);
    border: 1.5px solid #4ade80;
    border-radius: 14px;
    padding: 18px 20px;
    margin: 24px 0;
    position: relative;
    box-shadow: 0 2px 10px rgba(16,185,129,0.07);
}

.quick-help::before {
    content: '💡';
    position: absolute;
    top: -12px;
    left: 22px;
    background: #fff;
    padding: 0 10px;
    font-size: 1.3rem;
}

.quick-help-title {
    font-weight: 700;
    color: #059669;
    margin-bottom: 10px;
    margin-left: 24px;
}

.quick-help-content {
    color: #047857;
    font-size: 1rem;
    line-height: 1.6;
}

/* Support Box */
.support-box {
    background: linear-gradient(120deg, #e0f2fe 60%, #f3e8ff 100%);
    border: 1.5px solid #38bdf8;
    border-radius: 14px;
    padding: 28px 22px;
    text-align: center;
    margin: 32px 0;
    box-shadow: 0 2px 10px rgba(59,130,246,0.07);
}

.support-title {
    color: #2563eb;
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 14px;
}

.support-content {
    color: #1e40af;
    font-size: 1rem;
    margin-bottom: 18px;
}

.support-buttons {
    display: flex;
    gap: 14px;
    justify-content: center;
    flex-wrap: wrap;
}

.support-button {
    padding: 10px 22px;
    background: linear-gradient(120deg, #38bdf8 60%, #6366f1 100%);
    color: #fff;
    border: none;
    border-radius: 22px;
    text-decoration: none;
    font-size: 1rem;
    font-weight: 600;
    transition: all 0.25s cubic-bezier(.4,0,.2,1);
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(59,130,246,0.10);
}

.support-button:hover {
    transform: translateY(-2px) scale(1.04);
    box-shadow: 0 6px 18px rgba(59,130,246,0.18);
}

/* Phone mockup styles */
.phone-mockup {
    width: 320px;
    height: 640px;
    background: linear-gradient(145deg, #2c2c2c, #1a1a1a);
    border-radius: 32px; /* giảm từ 38px */
    padding: 8px;        /* giảm từ 10px */
    margin: 18px auto;
    position: relative;
    box-shadow: 0 12px 32px rgba(0,0,0,0.22);
    transition: box-shadow 0.3s, transform 0.3s;
}

.phone-mockup:hover {
    transform: translateY(-4px) scale(1.02);
    box-shadow: 0 20px 48px rgba(0,0,0,0.28);
}

.phone-screen {
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #f8fafc 0%, #e0e7ff 100%);
    border-radius: 26px; /* giảm từ 32px */
    overflow: hidden;
    position: relative;
    box-shadow: 0 2px 10px rgba(102,126,234,0.07);
}

/* Tối ưu hiệu ứng chuyển động và shadow */
.guide-section,
.guide-nav,
.feature-item,
.faq-section,
.faq-item,
.support-box,
.quick-help {
    will-change: transform, box-shadow, opacity;
}

/* Giảm độ mạnh box-shadow để nhẹ hơn */
.guide-section,
.guide-nav,
.faq-section,
.support-box,
.quick-help,
.feature-item,
.faq-item {
    box-shadow: 0 2px 8px rgba(102,126,234,0.06);
    transition: transform 0.18s cubic-bezier(.4,0,.2,1), box-shadow 0.18s;
}

/* Giảm hiệu ứng hover cho mobile */
@media (hover: hover) and (pointer: fine) {
    .guide-section:hover {
        transform: translateY(-2px) scale(1.005);
        box-shadow: 0 6px 16px rgba(102,126,234,0.10);
    }
    .nav-item:hover, .nav-item.active {
        border-color: #6366f1;
        background: linear-gradient(120deg, #6366f1 60%, #818cf8 100%);
        color: #fff;
        box-shadow: 0 3px 8px rgba(102,126,234,0.10);
        transform: translateY(-1px) scale(1.01);
    }
    .control-button:hover {
        transform: scale(1.05);
        box-shadow: 0 2px 6px rgba(0,0,0,0.18);
    }
    .action-button:hover {
        transform: scale(1.01);
    }
}

/* Giảm số lượng animation lặp vô hạn */
.gesture-arrow,
.swipe-left,
.swipe-right,
.swipe-up {
    animation-duration: 2.5s;
    animation-iteration-count: 2;
}

/* Tối ưu animation: chỉ chạy khi hiển thị */
.fade-in {
    animation: fadeIn 0.4s cubic-bezier(.4,0,.2,1);
}
.slide-in {
    animation: slideIn 0.35s cubic-bezier(.4,0,.2,1);
}
.pulse {
    animation: pulse 1.2s 2;
}

/* Tối ưu transition cho các nút */
.control-button,
.action-button,
.bottom-button,
.demo-button {
    transition: transform 0.15s cubic-bezier(.4,0,.2,1), box-shadow 0.15s;
}

/* Review guide specific styles */
.card-area {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: linear-gradient(135deg, #f8f9fa 0%, #ffffff 100%);
}

.vocabulary-card {
    width: 250px;
    height: 350px;
    background: linear-gradient(135deg, #ff6b6b 0%, #ee5a52 100%);
    border-radius: 20px;
    padding: 30px;
    color: white;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    box-shadow: 0 15px 35px rgba(0,0,0,0.2);
    position: relative;
    cursor: pointer;
    transition: transform 0.3s ease;
}

.vocabulary-card:hover {
    transform: translateY(-5px);
}

.card-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    text-align: center;
}

.vietnamese-text {
    font-size: 1.8rem;
    font-weight: bold;
    margin-bottom: 15px;
}

.chinese-text {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 10px;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.chinese-text.visible {
    opacity: 1;
}

.example-text {
    font-size: 0.9rem;
    opacity: 0.9;
    margin-top: 15px;
    padding: 10px;
    background: rgba(0,0,0,0.1);
    border-radius: 8px;
}

.card-controls {
    position: absolute;
    bottom: 100px;
    left: 20px;
    right: 20px;
    display: flex;
    justify-content: space-around;
}

.control-button {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    border: none;
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.undo-btn {
    background: linear-gradient(45deg, #3498db, #2980b9);
}

.wrong-btn {
    background: linear-gradient(45deg, #e74c3c, #c0392b);
}

.correct-btn {
    background: linear-gradient(45deg, #27ae60, #229954);
}

.control-button:hover {
    transform: scale(1.1);
    box-shadow: 0 5px 15px rgba(0,0,0,0.3);
}

.button-labels {
    position: absolute;
    bottom: 40px;
    left: 0;
    right: 0;
    display: flex;
    justify-content: space-around;
    padding: 0 20px;
}

.button-label {
    font-size: 0.8rem;
    color: #666;
    text-align: center;
}

.swipe-card {
    width: 80px;
    height: 80px;
    background: linear-gradient(45deg, #667eea, #764ba2);
    border-radius: 10px;
    position: absolute;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
}

.swipe-left {
    animation: swipeLeft 3s infinite;
}

.swipe-right {
    animation: swipeRight 3s infinite;
}

.swipe-up {
    animation: swipeUp 3s infinite;
}

@keyframes swipeLeft {
    0%, 100% { transform: translateX(0) rotate(0deg); opacity: 1; }
    50% { transform: translateX(-60px) rotate(-15deg); opacity: 0.5; }
}

@keyframes swipeRight {
    0%, 100% { transform: translateX(0) rotate(0deg); opacity: 1; }
    50% { transform: translateX(60px) rotate(15deg); opacity: 0.5; }
}

@keyframes swipeUp {
    0%, 100% { transform: translateY(0) rotate(0deg); opacity: 1; }
    50% { transform: translateY(-60px) rotate(5deg); opacity: 0.5; }
}

.stats-display {
    background: rgba(255, 255, 255, 0.9);
    padding: 15px;
    border-radius: 10px;
    margin: 15px 0;
    display: flex;
    justify-content: space-around;
}

/* Enhanced responsive design for new elements */
@media (max-width: 768px) {
    .phone-mockup {
        width: 260px;
        height: 520px;
    }
    
    .container {
        padding: 12px;
    }
    
    .header h1 {
        font-size: 1.6rem;
    }
    
    .header p {
        font-size: 0.9rem;
    }
    
    .guide-section {
        padding: 15px;
        margin-bottom: 15px;
        border-radius: 10px;
        box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    }
    
    .section-title {
        font-size: 1.2rem;
        gap: 8px;
    }
    
    .section-title .icon {
        font-size: 1.3rem;
    }
    
    .feature-list {
        grid-template-columns: 1fr;
        gap: 12px;
    }
    
    .feature-item {
        padding: 12px;
    }
    
    .feature-item h4 {
        font-size: 0.9rem;
    }
    
    .feature-item p {
        font-size: 0.85rem;
    }
    
    .question-text {
        font-size: 1.6rem;
    }
    
    .bottom-button {
        width: 38px;
        height: 38px;
        font-size: 1.1rem;
    }
    
    .demo-controls {
        gap: 6px;
    }
    
    .demo-button {
        padding: 6px 12px;
        font-size: 0.8rem;
    }
    
    .tip-box {
        padding: 10px;
        font-size: 0.85rem;
    }
    
    .animation-demo {
        flex-direction: column;
        gap: 20px;
    }
    
    .guide-nav {
        padding: 15px;
        margin-bottom: 20px;
    }
    
    .nav-grid {
        grid-template-columns: 1fr;
        gap: 8px;
    }
    
    .nav-item {
        padding: 10px 12px;
        font-size: 0.85rem;
    }
    
    .faq-section {
        padding: 20px 15px;
    }
    
    .faq-grid {
        grid-template-columns: 1fr;
        gap: 12px;
    }
    
    .faq-item {
        padding: 12px;
    }
    
    .support-buttons {
        flex-direction: column;
        align-items: center;
    }
}

@media (max-width: 480px) {
    .phone-mockup {
        width: 240px;
        height: 480px;
    }
    
    .header h1 {
        font-size: 1.2rem;
    }
    
    .container {
        padding: 10px;
    }
    
    .guide-section {
        padding: 10px;
        margin-bottom: 10px;
    }
    
    .section-title {
        font-size: 1rem;
    }
    
    .main-title {
        font-size: 1.2rem;
    }
    
    .question-text {
        font-size: 1.2rem;
    }
    
    .guide-nav {
        padding: 12px;
    }
    
    .nav-title {
        font-size: 1.1rem;
    }
    
    .nav-item {
        padding: 8px 10px;
        font-size: 0.8rem;
    }
    
    .faq-section {
        padding: 15px 12px;
    }
    
    .faq-title {
        font-size: 1.3rem;
    }
}

/* Review guide specific styles */
.card-area {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: linear-gradient(135deg, #f8f9fa 0%, #ffffff 100%);
}

.vocabulary-card {
    width: 250px;
    height: 350px;
    background: linear-gradient(135deg, #ff6b6b 0%, #ee5a52 100%);
    border-radius: 20px;
    padding: 30px;
    color: white;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    box-shadow: 0 15px 35px rgba(0,0,0,0.2);
    position: relative;
    cursor: pointer;
    transition: transform 0.3s ease;
}

.vocabulary-card:hover {
    transform: translateY(-5px);
}

.card-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    text-align: center;
}

.vietnamese-text {
    font-size: 1.8rem;
    font-weight: bold;
    margin-bottom: 15px;
}

.chinese-text {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 10px;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.chinese-text.visible {
    opacity: 1;
}

.example-text {
    font-size: 0.9rem;
    opacity: 0.9;
    margin-top: 15px;
    padding: 10px;
    background: rgba(0,0,0,0.1);
    border-radius: 8px;
}

.card-controls {
    position: absolute;
    bottom: 100px;
    left: 20px;
    right: 20px;
    display: flex;
    justify-content: space-around;
}

.control-button {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    border: none;
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.undo-btn {
    background: linear-gradient(45deg, #3498db, #2980b9);
}

.wrong-btn {
    background: linear-gradient(45deg, #e74c3c, #c0392b);
}

.correct-btn {
    background: linear-gradient(45deg, #27ae60, #229954);
}

.control-button:hover {
    transform: scale(1.1);
    box-shadow: 0 5px 15px rgba(0,0,0,0.3);
}

.button-labels {
    position: absolute;
    bottom: 40px;
    left: 0;
    right: 0;
    display: flex;
    justify-content: space-around;
    padding: 0 20px;
}

.button-label {
    font-size: 0.8rem;
    color: #666;
    text-align: center;
}

.swipe-card {
    width: 80px;
    height: 80px;
    background: linear-gradient(45deg, #667eea, #764ba2);
    border-radius: 10px;
    position: absolute;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
}

.swipe-left {
    animation: swipeLeft 3s infinite;
}

.swipe-right {
    animation: swipeRight 3s infinite;
}

.swipe-up {
    animation: swipeUp 3s infinite;
}

@keyframes swipeLeft {
    0%, 100% { transform: translateX(0) rotate(0deg); opacity: 1; }
    50% { transform: translateX(-60px) rotate(-15deg); opacity: 0.5; }
}

@keyframes swipeRight {
    0%, 100% { transform: translateX(0) rotate(0deg); opacity: 1; }
    50% { transform: translateX(60px) rotate(15deg); opacity: 0.5; }
}

@keyframes swipeUp {
    0%, 100% { transform: translateY(0) rotate(0deg); opacity: 1; }
    50% { transform: translateY(-60px) rotate(5deg); opacity: 0.5; }
}

.stats-display {
    background: rgba(255, 255, 255, 0.9);
    padding: 15px;
    border-radius: 10px;
    margin: 15px 0;
    display: flex;
    justify-content: space-around;
}

/* Enhanced responsive design for review guide */
@media (max-width: 768px) {
    .phone-mockup {
        width: 240px;
        height: 480px;
    }
    
    .container {
        padding: 10px;
    }
    
    .header h1 {
        font-size: 1.4rem;
    }
    
    .header p {
        font-size: 0.9rem;
    }
    
    .guide-section {
        padding: 10px;
        margin-bottom: 10px;
    }
    
    .section-title {
        font-size: 1rem;
    }
    
    .main-title {
        font-size: 1.2rem;
    }
    
    .question-text {
        font-size: 1.2rem;
    }
    
    .vocabulary-card {
        width: 200px;
        height: 300px;
        padding: 20px;
    }
    
    .vietnamese-text {
        font-size: 1.4rem;
    }
    
    .chinese-text {
        font-size: 1.8rem;
    }
    
    .control-button {
        width: 50px;
        height: 50px;
        font-size: 1.3rem;
    }
}

@media (max-width: 480px) {
    .phone-mockup {
        width: 200px;
        height: 400px;
    }
    
    .header h1 {
        font-size: 1.2rem;
    }
    
    .guide-section {
        padding: 10px;
        margin-bottom: 10px;
    }
    
    .section-title {
        font-size: 1rem;
    }
    
    .main-title {
        font-size: 1.2rem;
    }
    
    .question-text {
        font-size: 1.2rem;
    }
    
    .vocabulary-card {
        width: 180px;
        height: 260px;
        padding: 15px;
    }
    
    .vietnamese-text {
        font-size: 1.2rem;
    }
    
    .chinese-text {
        font-size: 1.6rem;
    }
    
    .control-button {
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }
}