/* ===== CSS变量 ===== */
:root {
    /* 颜色 */
    --color-primary: #00d4ff;
    --color-secondary: #a855f7;
    --color-accent: #00ffff;
    --color-bg-dark: #0a0a0f;
    --color-bg-darker: #06060a;
    --color-bg-card: rgba(26, 26, 46, 0.6);
    --color-bg-card-hover: rgba(26, 26, 46, 0.8);
    --color-text: #ffffff;
    --color-text-secondary: #e5e7eb;
    --color-text-muted: #9ca3af;
    --color-border: rgba(148, 163, 184, 0.1);
    
    /* 渐变 */
    --gradient-primary: linear-gradient(135deg, #00d4ff 0%, #a855f7 100%);
    --gradient-bg: linear-gradient(135deg, #0c0c0c 0%, #1a1a2e 50%, #16213e 100%);
    
    /* 间距 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 4rem;
    
    /* 其他 */
    --border-radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 20px rgba(0, 212, 255, 0.3);
}

/* ===== 基础样式 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'SF Pro Display', Roboto, sans-serif;
    background: var(--gradient-bg);
    color: var(--color-text);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
    position: relative;
}

body.menu-open {
    overflow: hidden;
}

/* ===== 容器 ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(10, 10, 15, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
    transition: var(--transition);
}

.navbar.scrolled {
    background: rgba(10, 10, 15, 0.95);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.navbar.nav-hidden {
    transform: translateY(-100%);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    transition: var(--transition);
}

.logo:hover {
    filter: brightness(1.2);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    list-style: none;
}

.nav-menu a {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

.nav-menu a:not(.btn-primary):hover,
.nav-menu a.active {
    color: var(--color-primary);
}

.nav-menu a:not(.btn-primary)::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: var(--transition);
}

.nav-menu a:not(.btn-primary):hover::after,
.nav-menu a.active::after {
    width: 100%;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    padding: 0.5rem 1.5rem;
    border-radius: 50px;
    font-weight: 600;
    transition: var(--transition);
}

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

/* 移动端菜单按钮 */
.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 2px;
    background: var(--color-text);
    transition: var(--transition);
}

.mobile-menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.mobile-menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
}

/* ===== 英雄区 ===== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 100px var(--spacing-lg) var(--spacing-xxl);
    position: relative;
}

.hero-container {
    max-width: 1200px;
    width: 100%;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xxl);
    align-items: center;
}

.ai-avatar-container {
    display: flex;
    justify-content: center;
    align-items: center;
}

#ai-avatar {
    max-width: 100%;
    height: auto;
    filter: drop-shadow(0 0 40px rgba(0, 212, 255, 0.3));
}

.hero-content {
    text-align: left;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

.gradient-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

.hero-features {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.hero-feature {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--color-text-secondary);
    font-size: 0.95rem;
}

.hero-feature .feature-icon {
    width: 24px;
    height: 24px;
    color: var(--color-primary);
}

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

.btn-hero {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    background: var(--gradient-primary);
    color: white;
    padding: 1rem 2rem;
    border-radius: 50px;
    font-weight: 600;
    font-size: 1.1rem;
    text-decoration: none;
    transition: var(--transition);
}

.btn-hero:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(0, 212, 255, 0.4);
}

.btn-hero svg {
    width: 20px;
    height: 20px;
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    color: white;
    padding: 1rem 2rem;
    border-radius: 50px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    font-weight: 600;
    font-size: 1.1rem;
    text-decoration: none;
    transition: var(--transition);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.3);
    transform: translateY(-3px);
}

/* ===== 功能区 ===== */
.features-section {
    padding: var(--spacing-xxl) 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-md);
}

.section-subtitle {
    text-align: center;
    color: var(--color-text-secondary);
    font-size: 1.1rem;
    margin-bottom: var(--spacing-xxl);
}

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

.feature-card {
    background: var(--color-bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-xl);
    transition: var(--transition);
}

.feature-card:hover {
    background: var(--color-bg-card-hover);
    transform: translateY(-5px);
    box-shadow: var(--shadow);
    border-color: rgba(0, 212, 255, 0.3);
}

.feature-icon-box {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
}

.feature-icon-box svg {
    width: 32px;
    height: 32px;
    color: white;
    stroke-width: 2;
}

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

.feature-card p {
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.7;
}

.btn-preview {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
}

.btn-preview:hover {
    gap: 0.75rem;
}

.btn-preview svg {
    width: 18px;
    height: 18px;
}

/* ===== 页面标题 ===== */
.page-header {
    padding: 120px var(--spacing-lg) var(--spacing-xxl);
    text-align: center;
}

.page-header h1 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: var(--spacing-md);
}

.page-header p {
    font-size: 1.2rem;
    color: var(--color-text-secondary);
}

.update-date {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    margin-top: var(--spacing-sm);
}

/* ===== 功能详情页 ===== */
.features-detail {
    padding: 0 0 var(--spacing-xxl);
}

.feature-detail-card {
    background: var(--color-bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.feature-detail-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.feature-detail-icon {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.feature-detail-icon svg {
    width: 32px;
    height: 32px;
    color: white;
}

.feature-detail-header h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.feature-badge {
    display: inline-block;
    background: rgba(0, 212, 255, 0.2);
    color: var(--color-primary);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.feature-badge.recommended {
    background: rgba(168, 85, 247, 0.2);
    color: var(--color-secondary);
}

.feature-description {
    font-size: 1.1rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.8;
}

.feature-list {
    list-style: none;
    margin-bottom: var(--spacing-lg);
}

.feature-list li {
    padding-left: 1.5rem;
    margin-bottom: 0.75rem;
    position: relative;
    color: var(--color-text-secondary);
    line-height: 1.7;
}

.feature-list li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--color-primary);
    font-weight: bold;
}

.feature-video {
    margin-top: var(--spacing-lg);
    border-radius: var(--border-radius);
    overflow: hidden;
    aspect-ratio: 16/9;
}

.feature-video iframe {
    width: 100%;
    height: 100%;
    border: none;
}

.btn-demo {
    display: inline-flex;
    align-items: center;
    background: rgba(0, 212, 255, 0.1);
    color: var(--color-primary);
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    border: 1px solid rgba(0, 212, 255, 0.3);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
}

.btn-demo:hover {
    background: rgba(0, 212, 255, 0.2);
    border-color: rgba(0, 212, 255, 0.5);
    transform: translateY(-2px);
}

.demo-links {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

/* ===== 安装指南 ===== */
.install-section {
    padding: 0 0 var(--spacing-xxl);
}

.install-method {
    background: var(--color-bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.install-method-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.install-number {
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    flex-shrink: 0;
}

.install-method-header h2 {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
}

.install-badge {
    display: inline-block;
    background: rgba(148, 163, 184, 0.2);
    color: var(--color-text-secondary);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.install-description {
    font-size: 1.1rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-lg);
}

.install-steps {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.step {
    display: flex;
    gap: var(--spacing-md);
}

.step-number {
    width: 40px;
    height: 40px;
    background: rgba(0, 212, 255, 0.2);
    color: var(--color-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    flex-shrink: 0;
}

.step-content {
    flex: 1;
}

.step-content h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
}

.step-content p {
    color: var(--color-text-secondary);
    margin-bottom: 0.75rem;
    line-height: 1.7;
}

.step-note {
    font-size: 0.9rem;
    color: var(--color-text-muted);
    margin-top: 0.5rem;
}

.btn-install {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--gradient-primary);
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    margin-top: 0.5rem;
}

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

.btn-install svg {
    width: 18px;
    height: 18px;
}

.code-block {
    background: rgba(0, 0, 0, 0.5);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: var(--spacing-md);
    margin: var(--spacing-sm) 0;
    overflow-x: auto;
}

.code-block code {
    font-family: 'Monaco', 'Menlo', 'Courier New', monospace;
    font-size: 0.9rem;
    color: var(--color-primary);
    white-space: pre;
    display: block;
}

.requirements-list,
.numbered-list {
    margin-left: 1.5rem;
    margin-bottom: var(--spacing-md);
}

.requirements-list li,
.numbered-list li {
    color: var(--color-text-secondary);
    margin-bottom: 0.5rem;
    line-height: 1.7;
}

.subsection-title {
    font-size: 1.5rem;
    margin: var(--spacing-lg) 0 var(--spacing-md);
    color: var(--color-primary);
}

.video-tutorials {
    margin-top: var(--spacing-xxl);
}

.video-tutorials h2 {
    font-size: 2rem;
    margin-bottom: var(--spacing-lg);
}

.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--spacing-lg);
}

.video-card {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
}

.video-card h3 {
    margin-bottom: var(--spacing-md);
}

.video-container {
    border-radius: 8px;
    overflow: hidden;
    aspect-ratio: 16/9;
}

.video-container iframe {
    width: 100%;
    height: 100%;
    border: none;
}

.faq-section {
    margin-top: var(--spacing-xxl);
}

.faq-section h2 {
    font-size: 2rem;
    margin-bottom: var(--spacing-lg);
}

.faq-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.faq-item {
    background: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
}

.faq-item h3 {
    font-size: 1.3rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

.faq-item p {
    color: var(--color-text-secondary);
    line-height: 1.7;
}

/* ===== 隐私政策 ===== */
.privacy-section {
    padding: 0 0 var(--spacing-xxl);
}

.privacy-highlight {
    background: rgba(168, 85, 247, 0.1);
    border: 2px solid var(--color-secondary);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.privacy-highlight h2 {
    color: var(--color-secondary);
    margin-bottom: var(--spacing-sm);
}

.privacy-highlight p {
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: 0.5rem;
}

.privacy-card {
    background: var(--color-bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-lg);
}

.privacy-card h2 {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.8rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-primary);
}

.privacy-card h2 svg {
    width: 28px;
    height: 28px;
}

.privacy-card p {
    color: var(--color-text-secondary);
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
}

.privacy-card ul {
    list-style: none;
    margin: var(--spacing-md) 0;
}

.privacy-card ul li {
    padding-left: 1.5rem;
    margin-bottom: 0.75rem;
    position: relative;
    color: var(--color-text-secondary);
    line-height: 1.7;
}

.privacy-card ul li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--color-primary);
    font-weight: bold;
}

.privacy-card a {
    color: var(--color-primary);
    text-decoration: none;
    transition: var(--transition);
}

.privacy-card a:hover {
    text-decoration: underline;
}

/* ===== CTA区域 ===== */
.cta-section {
    padding: var(--spacing-xxl) 0;
    text-align: center;
}

.cta-section h2 {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-md);
}

.cta-section p {
    font-size: 1.2rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xl);
}

/* ===== 底部 ===== */
.footer {
    background: rgba(6, 6, 10, 0.8);
    backdrop-filter: blur(20px);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-xxl) 0 var(--spacing-lg);
    margin-top: var(--spacing-xxl);
}

.footer-content {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-brand h3 {
    margin-bottom: var(--spacing-sm);
}

.footer-brand p {
    color: var(--color-text-secondary);
}

.footer-column h4 {
    margin-bottom: var(--spacing-md);
    color: var(--color-primary);
}

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

.footer-column ul li {
    margin-bottom: 0.5rem;
}

.footer-column a {
    color: var(--color-text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

.footer-column a:hover {
    color: var(--color-primary);
}

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

/* ===== 语言切换按钮 ===== */
.lang-toggle {
    display: flex;
    align-items: center;
}

.lang-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    padding: 0.5rem 1rem;
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: var(--transition);
}

.lang-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.2);
    color: var(--color-primary);
}

.lang-btn svg {
    width: 18px;
    height: 18px;
}

.lang-text {
    font-weight: 600;
    font-size: 0.9rem;
}

/* ===== 返回顶部按钮 ===== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    opacity: 0;
    visibility: hidden;
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-glow);
}

.back-to-top svg {
    width: 24px;
    height: 24px;
    color: white;
}

/* ===== 动画 ===== */
.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-on-scroll.animate-in {
    opacity: 1;
    transform: translateY(0);
}

/* ===== 响应式设计 ===== */
@media (max-width: 1024px) {
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-content {
        text-align: center;
    }
    
    .hero-cta {
        justify-content: center;
    }
    
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: rgba(10, 10, 15, 0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: var(--spacing-lg);
        transform: translateX(100%);
        transition: var(--transition);
        border-top: 1px solid var(--color-border);
        max-height: calc(100vh - 70px);
        overflow-y: auto;
    }
    
    .nav-menu.active {
        transform: translateX(0);
    }
    
    .lang-toggle {
        width: 100%;
    }
    
    .lang-btn {
        width: 100%;
        justify-content: center;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-features {
        grid-template-columns: 1fr;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
    
    .video-grid {
        grid-template-columns: 1fr;
    }
    
    .feature-detail-header {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-lg: 1rem;
        --spacing-xl: 2rem;
        --spacing-xxl: 3rem;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-cta {
        flex-direction: column;
    }
    
    .btn-hero,
    .btn-secondary {
        width: 100%;
        justify-content: center;
    }
    
    .page-header h1 {
        font-size: 2rem;
    }
}