/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* App Color Palette - Matching Flutter App Theme */
    --primary-blue: #4D9DF6;
    --primary-blue-pressed: #3E86D6;
    --primary-blue-disabled: #2C3B47;
    --accent-color: #50E3C2;
    
    /* Background Colors */
    --bg-primary: #12161C;
    --bg-secondary: #192029;
    --bg-surface: #1F262F;
    --bg-dark: #000000;
    
    /* Text Colors */
    --text-primary: #E8ECEF;
    --text-secondary: #AAB4BE;
    --text-muted: #6A737D;
    --text-white: #FFFFFF;
    
    /* Border Colors */
    --border-color: #2A3138;
    
    /* Emotion Colors (Low Saturation) */
    --emotion-joy: #F6D96A;
    --emotion-trust: #4D9DF6;
    --emotion-fear: #9B7EDE;
    --emotion-surprise: #50E3C2;
    --emotion-sadness: #778CA0;
    --emotion-disgust: #8FA87A;
    --emotion-anger: #E85B5B;
    --emotion-anticipation: #E9955B;
    
    /* Error Color */
    --error-color: #E85B5B;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-2xl: 20px;
    --radius-3xl: 24px;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'WenQuanYi Micro Hei', 'Helvetica Neue', Arial, sans-serif;
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    background: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Navigation - App Style */
.navbar {
    background: rgba(18, 22, 28, 0.95);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: var(--spacing-md) 0;
    border-bottom: 1px solid var(--border-color);
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
    letter-spacing: -0.5px;
    transition: var(--transition-base);
}

.logo:hover {
    color: var(--primary-blue);
    transform: scale(1.02);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition-fast);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-lg);
    position: relative;
}

.nav-links a:hover {
    color: var(--primary-blue);
    background: rgba(77, 157, 246, 0.1);
}

.language-selector {
    display: flex;
    gap: var(--spacing-xs);
    margin-left: var(--spacing-md);
    background: var(--bg-surface);
    padding: 4px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.lang-btn {
    padding: 0.5rem 1rem;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    font-weight: 500;
    transition: var(--transition-fast);
    text-decoration: none;
    display: inline-block;
}

.lang-btn:hover {
    color: var(--primary-blue);
    background: rgba(77, 157, 246, 0.1);
}

.lang-btn.active {
    background: var(--primary-blue);
    color: var(--bg-primary);
    font-weight: 600;
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
    border-radius: var(--radius-lg);
    transition: var(--transition-fast);
}

.mobile-menu-toggle:hover {
    background: rgba(77, 157, 246, 0.1);
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: var(--radius-full);
    transition: var(--transition-fast);
}

/* Hero Section - App Style */
.hero {
    background: var(--bg-primary);
    padding: var(--spacing-2xl) 0;
    min-height: 90vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 20% 50%, rgba(77, 157, 246, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(80, 227, 194, 0.08) 0%, transparent 50%);
    pointer-events: none;
}

.hero .container {
    position: relative;
    z-index: 1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    align-items: center;
}

.hero-content {
    animation: fadeInUp 0.8s ease;
}

.hero-title {
    font-size: 5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    letter-spacing: -0.5px;
    line-height: 1.1;
    position: relative;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.7;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.btn {
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-xl);
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    transition: var(--transition-base);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: none;
    cursor: pointer;
    min-height: 48px;
}

.btn-primary {
    background: var(--primary-blue);
    color: var(--bg-primary);
    font-weight: 600;
}

.btn-primary:hover {
    background: var(--primary-blue-pressed);
    transform: translateY(-1px);
}

.btn-secondary {
    background: transparent;
    color: var(--primary-blue);
    border: 1.5px solid var(--primary-blue);
}

.btn-secondary:hover {
    background: rgba(77, 157, 246, 0.1);
    transform: translateY(-1px);
}

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
    animation: fadeInRight 0.8s ease;
}

.phone-mockup {
    width: 320px;
    height: 693px;
    background: var(--bg-secondary);
    border-radius: 40px;
    padding: 10px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5), 0 0 0 2px var(--border-color);
    position: relative;
}

.phone-screen {
    width: 100%;
    height: 100%;
    background: var(--bg-primary);
    border-radius: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-xl);
    overflow: hidden;
    position: relative;
    border: 1px solid var(--border-color);
}

.phone-screen::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 30% 30%, rgba(77, 157, 246, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 70% 70%, rgba(80, 227, 194, 0.08) 0%, transparent 50%);
    z-index: 1;
}

.phone-screenshot {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 24px;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 2;
    display: none;
}

.phone-screenshot[src]:not([src=""]) {
    display: block;
}

.phone-screenshot[src]:not([src=""]) ~ .hexagram-demo,
.phone-screenshot[src]:not([src=""]) ~ .emotion-demo {
    display: none;
}

.hexagram-demo {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    width: 100%;
    position: relative;
    z-index: 1;
}

.hexagram-line {
    height: 12px;
    background: var(--primary-blue);
    border-radius: var(--radius-md);
    animation: pulse 2s ease-in-out infinite;
    box-shadow: 0 2px 12px rgba(77, 157, 246, 0.3), 0 0 20px rgba(77, 157, 246, 0.15);
}

.hexagram-line:nth-child(2n) {
    opacity: 0.8;
    width: 85%;
    margin-left: auto;
    background: rgba(77, 157, 246, 0.6);
}

.hexagram-line:nth-child(1) { animation-delay: 0s; }
.hexagram-line:nth-child(2) { animation-delay: 0.2s; }
.hexagram-line:nth-child(3) { animation-delay: 0.4s; }
.hexagram-line:nth-child(4) { animation-delay: 0.6s; }
.hexagram-line:nth-child(5) { animation-delay: 0.8s; }
.hexagram-line:nth-child(6) { animation-delay: 1s; }

/* Emotion Demo */
.emotion-demo {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    width: 100%;
    position: relative;
    z-index: 1;
    justify-content: center;
    align-items: center;
    padding: var(--spacing-lg);
}

.emotion-circle {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    animation: float 3s ease-in-out infinite;
    box-shadow: 0 4px 20px rgba(77, 157, 246, 0.2), 0 0 30px rgba(77, 157, 246, 0.1);
    backdrop-filter: blur(10px);
}

.emotion-circle:nth-child(1) { animation-delay: 0s; }
.emotion-circle:nth-child(2) { animation-delay: 0.5s; }
.emotion-circle:nth-child(3) { animation-delay: 1s; }
.emotion-circle:nth-child(4) { animation-delay: 1.5s; }

.emotion-joy {
    background: rgba(246, 217, 106, 0.2);
    border: 1px solid rgba(246, 217, 106, 0.4);
}

.emotion-trust {
    background: rgba(77, 157, 246, 0.2);
    border: 1px solid rgba(77, 157, 246, 0.4);
}

.emotion-fear {
    background: rgba(155, 126, 222, 0.2);
    border: 1px solid rgba(155, 126, 222, 0.4);
}

.emotion-surprise {
    background: rgba(80, 227, 194, 0.2);
    border: 1px solid rgba(80, 227, 194, 0.4);
}

/* Features Section - App Style */
.features {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-primary);
}

.section-title {
    font-size: 3rem;
    text-align: center;
    margin-bottom: var(--spacing-xl);
    color: var(--text-primary);
    font-weight: 600;
    letter-spacing: -1px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-lg);
}

.feature-card {
    background: var(--bg-secondary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-2xl);
    text-align: left;
    transition: var(--transition-base);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.feature-card:hover {
    transform: translateY(-4px);
    border-color: var(--primary-blue);
    background: var(--bg-surface);
}

.feature-icon {
    font-size: 3.5rem;
    margin-bottom: var(--spacing-md);
    display: inline-block;
    transform: scale(1);
    transition: var(--transition-base);
}

.feature-card:hover .feature-icon {
    transform: scale(1.05);
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
    font-weight: 600;
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 1rem;
}

/* About Section - App Style */
.about {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-primary);
    position: relative;
    overflow: hidden;
}

.about::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 10% 20%, rgba(77, 157, 246, 0.08) 0%, transparent 40%),
        radial-gradient(circle at 90% 80%, rgba(80, 227, 194, 0.06) 0%, transparent 40%);
    pointer-events: none;
}


.about .container {
    position: relative;
    z-index: 1;
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    align-items: center;
}

.about-text {
    background: var(--bg-secondary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-2xl);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

.about-text .section-title {
    margin-bottom: var(--spacing-lg);
    text-align: left;
}

.about-text p {
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
    line-height: 1.9;
    font-size: 1.125rem;
    position: relative;
    z-index: 1;
}

.about-text p:last-child {
    margin-bottom: 0;
}

.about-image {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

.about-image::before {
    content: '';
    position: absolute;
    width: 400px;
    height: 400px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(77, 157, 246, 0.1) 0%, transparent 70%);
    filter: blur(60px);
    animation: pulse-glow 3s ease-in-out infinite;
}

.about-image::after {
    content: '';
    position: absolute;
    width: 360px;
    height: 360px;
    border-radius: 50%;
    border: 2px solid var(--border-color);
    animation: rotate-reverse 20s linear infinite;
}

.yin-yang-symbol {
    width: 320px;
    height: 320px;
    position: relative;
    z-index: 1;
    filter: drop-shadow(0 0 40px rgba(77, 157, 246, 0.2));
    animation: float 6s ease-in-out infinite;
}

.yin-yang {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    background: linear-gradient(to right, #F8F3DA 50%, #0A0A0A 50%);
    position: relative;
    animation: rotate 30s linear infinite;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5), 0 0 0 4px rgba(248, 243, 218, 0.3);
    overflow: hidden;
}

/* 标准太极图S形曲线的上半部分：覆盖左侧上半部分的白色，使其变成黑色 */
.yin-yang::before {
    content: '';
    position: absolute;
    width: 50%;
    height: 50%;
    top: 0;
    left: 0;
    background: #0A0A0A;
    border-radius: 100% 0 0 100% / 50% 0 0 50%;
}

/* 标准太极图S形曲线的下半部分：覆盖右侧下半部分的黑色，使其变成白色 */
.yin-yang::after {
    content: '';
    position: absolute;
    width: 50%;
    height: 50%;
    bottom: 0;
    right: 0;
    background: #F8F3DA;
    border-radius: 0 100% 100% 0 / 0 50% 50% 0;
}

/* 黑色小圆点（阴眼）- 位于白色区域的中心（上半部分右侧的中心） */
.yin-yang-symbol::before {
    content: '';
    position: absolute;
    width: 12.5%;
    height: 12.5%;
    border-radius: 50%;
    background: #0A0A0A;
    top: 25%;
    right: 25%;
    z-index: 2;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
}

/* Emotion Visualization */
.emotion-visualization {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    width: 100%;
    min-height: 400px;
}

.emotion-wheel {
    position: relative;
    width: 360px;
    height: 360px;
    animation: float 6s ease-in-out infinite;
    overflow: hidden;
}

.emotion-item {
    position: absolute;
    width: 80px;
    height: 80px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    transition: border-color var(--transition-base);
    will-change: transform;
}

.emotion-item:hover {
    border-color: var(--primary-blue);
    z-index: 10;
}

/* 8个情绪围绕中心圆形排列 - 初始位置，JS会覆盖 */
.emotion-item:nth-child(1) {
    top: 0;
    left: 50%;
    transform: translateX(-50%);
}

.emotion-item:nth-child(2) {
    top: 50%;
    right: 0;
    transform: translateY(-50%);
}

.emotion-item:nth-child(3) {
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
}

.emotion-item:nth-child(4) {
    top: 50%;
    left: 0;
    transform: translateY(-50%);
}

.emotion-item:nth-child(5) {
    top: 15%;
    right: 15%;
}

.emotion-item:nth-child(6) {
    bottom: 15%;
    right: 15%;
}

.emotion-item:nth-child(7) {
    bottom: 15%;
    left: 15%;
}

.emotion-item:nth-child(8) {
    top: 15%;
    left: 15%;
}

/* 白色小圆点（阳眼）- 位于黑色区域的中心（下半部分左侧的中心） */
.yin-yang-symbol::after {
    content: '';
    position: absolute;
    width: 12.5%;
    height: 12.5%;
    border-radius: 50%;
    background: #F8F3DA;
    bottom: 25%;
    left: 25%;
    z-index: 2;
    box-shadow: 0 0 20px rgba(248, 243, 218, 0.5);
}

/* Account Deletion Notice Section */
.account-deletion-notice {
    padding: var(--spacing-xl) 0;
    background: var(--bg-primary);
    position: relative;
    overflow: hidden;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
}

.account-deletion-notice .container {
    position: relative;
    z-index: 1;
}

.notice-content {
    max-width: 900px;
    margin: 0 auto;
    background: var(--bg-secondary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-2xl);
    border: 1px solid var(--border-color);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.notice-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    display: inline-block;
    animation: float 3s ease-in-out infinite;
}

.notice-content h3 {
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    font-weight: 600;
    position: relative;
    z-index: 1;
}

.notice-content p {
    color: var(--text-secondary);
    line-height: 1.8;
    font-size: 1.0625rem;
    margin: 0;
    position: relative;
    z-index: 1;
}

/* Download Section - App Style */
.download {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-primary);
    color: var(--text-primary);
    text-align: center;
    position: relative;
    overflow: hidden;
    border-top: 1px solid var(--border-color);
}

.download .container {
    position: relative;
    z-index: 1;
}

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

.download-subtitle {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xl);
    color: var(--text-secondary);
    font-weight: 500;
}

.download-buttons {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.download-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-lg) var(--spacing-xl);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    text-decoration: none;
    color: var(--text-primary);
    transition: var(--transition-base);
    min-width: 240px;
}

.download-btn:hover {
    background: var(--bg-surface);
    border-color: var(--primary-blue);
    transform: translateY(-2px);
}

.download-icon {
    font-size: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.download-icon svg {
    width: 2.5rem;
    height: 2.5rem;
    color: var(--primary-blue);
}

.download-text {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
}

.download-label {
    font-size: 1.125rem;
    font-weight: 700;
    margin-bottom: 2px;
}

.download-coming-soon {
    font-size: 0.875rem;
    opacity: 0.9;
    font-weight: 500;
}

/* Footer - App Style */
.footer {
    background: var(--bg-primary);
    color: var(--text-primary);
    padding: var(--spacing-xl) 0 var(--spacing-md);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
    font-weight: 600;
}

.footer-section h3 {
    font-size: 1.5rem;
    color: var(--text-primary);
}

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

.footer-section ul li {
    margin-bottom: var(--spacing-xs);
}

.footer-section a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition-fast);
    font-size: 0.95rem;
}

.footer-section a:hover {
    color: var(--primary-blue);
    padding-left: 4px;
}

.footer-section p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
    font-size: 0.875rem;
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(40px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInRight {
    from {
        opacity: 0;
        transform: translateX(40px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
        transform: scaleX(1);
    }
    50% {
        opacity: 0.7;
        transform: scaleX(0.95);
    }
}

@keyframes rotate {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

@keyframes rotate-slow {
    from {
        transform: translateY(-50%) rotate(0deg);
    }
    to {
        transform: translateY(-50%) rotate(360deg);
    }
}

@keyframes twinkle {
    0%, 100% {
        opacity: 0.4;
        transform: translateY(-50%) scale(1);
    }
    50% {
        opacity: 0.8;
        transform: translateY(-50%) scale(1.2);
    }
}

@keyframes rotate-reverse {
    from {
        transform: rotate(360deg);
    }
    to {
        transform: rotate(0deg);
    }
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-20px);
    }
}

@keyframes pulse-glow {
    0%, 100% {
        opacity: 0.5;
        transform: scale(1);
    }
    50% {
        opacity: 0.8;
        transform: scale(1.1);
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: flex;
    }

    .nav-links {
        position: fixed;
        top: 72px;
        left: -100%;
        width: 100%;
        background: rgba(10, 10, 10, 0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: var(--spacing-xl);
        box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
        transition: var(--transition-base);
        z-index: 999;
        border-top: 1px solid var(--border-color);
    }

    .nav-links.active {
        left: 0;
    }

    .language-selector {
        margin-left: 0;
        margin-top: var(--spacing-md);
        width: 100%;
        flex-direction: column;
        align-items: stretch;
        gap: var(--spacing-xs);
    }
    
    .lang-btn {
        width: 100%;
        text-align: center;
    }

    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-title {
        font-size: 3.5rem;
        letter-spacing: 1px;
    }

    .hero-title::before,
    .hero-title::after {
        display: none;
    }

    .hero-subtitle {
        font-size: 1.25rem;
    }

    .hero-buttons {
        justify-content: center;
    }

    .phone-mockup {
        width: 280px;
        height: 606px;
    }

    .about-content {
        grid-template-columns: 1fr;
    }

    .about-text {
        padding: var(--spacing-lg);
    }

    .about-text .section-title {
        text-align: center;
        font-size: 2rem;
    }

    .about-image::before,
    .about-image::after {
        width: 300px;
        height: 300px;
    }

    .about-image::after {
        width: 280px;
        height: 280px;
    }

    .yin-yang-symbol {
        width: 240px;
        height: 240px;
    }

    .emotion-visualization {
        min-height: 300px;
    }

    .emotion-wheel {
        width: 280px;
        height: 280px;
    }

    .emotion-item {
        width: 60px;
        height: 60px;
        font-size: 2rem;
    }

    .emotion-demo {
        gap: var(--spacing-sm);
        padding: var(--spacing-md);
    }

    .emotion-circle {
        width: 50px;
        height: 50px;
        font-size: 1.5rem;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }

    .download-buttons {
        flex-direction: column;
        align-items: center;
    }

    .download-btn {
        width: 100%;
        max-width: 320px;
        justify-content: center;
    }

    .section-title {
        font-size: 2.25rem;
    }

    .notice-content {
        padding: var(--spacing-lg);
    }

    .notice-icon {
        font-size: 2.5rem;
    }

    .notice-content h3 {
        font-size: 1.25rem;
    }

    .notice-content p {
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 3rem;
        letter-spacing: 0.5px;
    }

    .logo::before,
    .logo::after {
        display: none;
    }

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

    .phone-mockup {
        width: 240px;
        height: 519px;
    }

    .btn {
        padding: 0.875rem 1.5rem;
        font-size: 0.95rem;
        min-height: 48px;
    }

    .feature-card {
        padding: var(--spacing-lg);
    }

    .notice-content {
        padding: var(--spacing-md);
    }

    .notice-icon {
        font-size: 2rem;
    }

    .notice-content h3 {
        font-size: 1.125rem;
    }

    .notice-content p {
        font-size: 0.9375rem;
    }

    .emotion-visualization {
        min-height: 250px;
    }

    .emotion-wheel {
        width: 240px;
        height: 240px;
    }

    .emotion-item {
        width: 50px;
        height: 50px;
        font-size: 1.75rem;
    }

    .emotion-circle {
        width: 40px;
        height: 40px;
        font-size: 1.25rem;
    }
}