/* ===== AI学习平台样式 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* AI主题色彩 */
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary-color: #7c3aed;
    --accent-color: #06b6d4;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    
    /* 渐变色 */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-ai: linear-gradient(135deg, #2563eb 0%, #7c3aed 100%);
    --gradient-neural: linear-gradient(135deg, #06b6d4 0%, #3b82f6 100%);
    
    /* 背景色 */
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: #334155;
    --bg-glass: rgba(255, 255, 255, 0.05);
    --bg-hover: rgba(255, 255, 255, 0.1);
    
    /* 文字颜色 */
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --text-accent: #60a5fa;
    
    /* 边框和阴影 */
    --border-color: rgba(255, 255, 255, 0.1);
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-glow: 0 0 20px rgba(37, 99, 235, 0.3);
    
    /* 圆角 */
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    
    /* 间距 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-primary);
    overflow-x: hidden;
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(15, 23, 42, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    padding: 0.75rem 0;
}

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

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.nav-logo i {
    color: var(--primary-color);
    font-size: 1.5rem;
}

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

.nav-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    transition: all 0.3s ease;
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
    background: var(--bg-hover);
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.bar {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: 0.3s;
}

/* ===== 主要内容 ===== */
.main-content {
    margin-top: 80px;
}

/* ===== 英雄区域 ===== */
.hero-section {
    padding: var(--spacing-2xl) 0;
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    position: relative;
    overflow: hidden;
}

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

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    align-items: center;
    min-height: 60vh;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: var(--spacing-md);
}

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

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.6;
}

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

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-lg);
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
}

.btn-primary {
    background: var(--gradient-ai);
    color: white;
    box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 30px rgba(37, 99, 235, 0.4);
}

.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--bg-hover);
    border-color: var(--primary-color);
}

/* ===== AI动画 ===== */
.ai-animation {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 400px;
}

.neural-network {
    position: relative;
    width: 300px;
    height: 300px;
}

.node {
    position: absolute;
    width: 20px;
    height: 20px;
    background: var(--gradient-neural);
    border-radius: 50%;
    animation: pulse 2s infinite;
}

.node:nth-child(1) { top: 50px; left: 50px; animation-delay: 0s; }
.node:nth-child(2) { top: 50px; right: 50px; animation-delay: 0.5s; }
.node:nth-child(3) { bottom: 50px; left: 50px; animation-delay: 1s; }
.node:nth-child(4) { bottom: 50px; right: 50px; animation-delay: 1.5s; }

.connection {
    position: absolute;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--accent-color), transparent);
    animation: flow 3s infinite;
}

.connection:nth-child(5) {
    top: 60px;
    left: 70px;
    width: 160px;
    transform: rotate(0deg);
}

.connection:nth-child(6) {
    top: 140px;
    left: 60px;
    width: 180px;
    transform: rotate(45deg);
}

.connection:nth-child(7) {
    top: 140px;
    left: 60px;
    width: 180px;
    transform: rotate(-45deg);
}

@keyframes pulse {
    0%, 100% { opacity: 0.6; transform: scale(1); }
    50% { opacity: 1; transform: scale(1.2); }
}

@keyframes flow {
    0% { opacity: 0; }
    50% { opacity: 1; }
    100% { opacity: 0; }
}

/* ===== 学习路径区域 ===== */
.learning-paths {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-secondary);
}

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

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-2xl);
    color: var(--text-primary);
}

.paths-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.path-card {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.path-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

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

.path-icon i {
    font-size: 1.5rem;
    color: white;
}

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

.path-card p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.path-progress {
    margin-top: var(--spacing-md);
}

.progress-text {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
    display: block;
}

.progress-bar {
    width: 100%;
    height: 6px;
    background: var(--bg-primary);
    border-radius: 3px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--gradient-ai);
    border-radius: 3px;
    transition: width 0.3s ease;
}

/* ===== 特色功能区域 ===== */
.features-section {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.feature-card {
    text-align: center;
    padding: var(--spacing-xl);
    background: var(--bg-glass);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
    background: var(--bg-hover);
}

.feature-icon {
    width: 80px;
    height: 80px;
    background: var(--gradient-neural);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-md);
}

.feature-icon i {
    font-size: 2rem;
    color: white;
}

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

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* ===== 页脚 ===== */
.footer {
    background: var(--bg-secondary);
    padding: var(--spacing-2xl) 0 var(--spacing-lg);
    border-top: 1px solid var(--border-color);
}

.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 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.footer-section p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.footer-link {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.social-links {
    display: flex;
    gap: var(--spacing-sm);
}

.social-link {
    width: 40px;
    height: 40px;
    background: var(--bg-card);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    text-decoration: none;
    transition: all 0.3s ease;
}

.social-link:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

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

.footer-bottom p {
    margin-bottom: var(--spacing-xs);
}

.icp-info {
    font-size: 0.875rem;
    margin-top: var(--spacing-sm);
}

.icp-link {
    color: var(--text-muted);
    text-decoration: none;
    transition: color 0.3s ease;
    border-bottom: 1px solid transparent;
}

.icp-link:hover {
    color: var(--text-secondary);
    border-bottom-color: var(--text-secondary);
}

/* ===== 关于页面样式 ===== */
.about-section {
    padding: var(--spacing-2xl) 0;
}

.about-header {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.about-content {
    max-width: 1200px;
    margin: 0 auto;
}

.intro-card,
.skills-card,
.philosophy-card {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    margin-bottom: var(--spacing-xl);
    border: 1px solid var(--border-color);
    backdrop-filter: blur(10px);
}

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

.card-header i {
    font-size: 1.5rem;
}

.card-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 0;
}

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

.intro-text p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: var(--spacing-md);
    font-size: 1.1rem;
}

.intro-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
}

.stat-item {
    text-align: center;
    padding: var(--spacing-lg);
    background: var(--bg-glass);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: var(--spacing-xs);
}

.stat-label {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.skill-category h3 {
    color: var(--text-primary);
    font-size: 1.2rem;
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.skill-category i {
    color: var(--accent-color);
}

.skill-items {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.skill-tag {
    background: var(--bg-glass);
    color: var(--text-secondary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.skill-tag:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

/* ===== 联系页面样式 ===== */
.contact-section {
    padding: var(--spacing-2xl) 0;
}

.contact-header {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.contact-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-2xl);
    max-width: 1200px;
    margin: 0 auto;
}

.contact-form-card,
.contact-info-card {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    border: 1px solid var(--border-color);
    backdrop-filter: blur(10px);
    height: fit-content;
}

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

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    color: var(--text-primary);
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.form-group label i {
    color: var(--primary-color);
    width: 16px;
}

.form-input,
.form-textarea {
    background: var(--bg-glass);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    color: var(--text-primary);
    font-size: 1rem;
    transition: all 0.3s ease;
    font-family: inherit;
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
    background: rgba(255, 255, 255, 0.05);
}

.form-textarea {
    resize: vertical;
    min-height: 120px;
}

.submit-btn {
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: var(--radius-lg);
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

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

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

.contact-method {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: var(--bg-glass);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.contact-method:hover {
    background: var(--bg-hover);
    transform: translateY(-2px);
}

.method-icon {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    flex-shrink: 0;
}

.method-content h3 {
    color: var(--text-primary);
    font-size: 1.1rem;
    margin-bottom: var(--spacing-xs);
}

.method-content p {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: var(--spacing-xs);
}

.method-desc {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.form-note {
    color: var(--text-muted);
    font-size: 0.9rem;
    text-align: center;
    margin-top: var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
}

.form-note i {
    color: var(--accent-color);
}

/* 表单错误样式 */
.error-message {
    color: #ef4444;
    font-size: 0.8rem;
    margin-top: var(--spacing-xs);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.error-message::before {
    content: "⚠️";
    font-size: 0.9rem;
}

/* 表单错误样式 */
.form-input.error,
.form-textarea.error {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px rgba(239, 68, 68, 0.1);
}

.error-message {
    color: var(--accent-color);
    font-size: 0.875rem;
    margin-top: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.error-message::before {
    content: "⚠";
    font-size: 1rem;
}

/* 加载状态样式 */
.btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
    pointer-events: none;
}

.btn .fa-spinner {
    animation: spin 1s linear infinite;
}

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

/* 懒加载图片样式 */
img.lazy {
    opacity: 0;
    transition: opacity 0.3s ease;
}

img.lazy.loaded {
    opacity: 1;
}

/* 平滑滚动 */
html {
    scroll-behavior: smooth;
}

/* 焦点可见性优化 */
.btn:focus-visible,
.nav-link:focus-visible,
.form-input:focus-visible,
.form-textarea:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* 触摸设备优化 */
@media (hover: none) and (pointer: coarse) {
    .btn:hover,
    .nav-link:hover,
    .path-card:hover,
    .feature-card:hover,
    .contact-method:hover,
    .skill-tag:hover {
        transform: none;
    }
    
    .btn:active,
    .nav-link:active {
        transform: scale(0.98);
    }
    
    /* 增大触摸目标 */
    .btn,
    .nav-link,
    .social-link,
    .footer-link,
    .skill-tag {
        min-height: 44px;
        min-width: 44px;
    }
}

/* 无障碍优化 */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    html {
        scroll-behavior: auto;
    }
}

/* 高对比度模式支持 */
@media (prefers-contrast: high) {
    .btn {
        border: 2px solid currentColor;
    }
    
    .card {
        border: 1px solid rgba(255, 255, 255, 0.3);
    }
}

/* 深色模式偏好 */
@media (prefers-color-scheme: dark) {
    /* 已经是深色主题，保持现有样式 */
}

/* 平板设备 (768px - 1024px) */
@media (max-width: 1024px) {
    .container {
        padding: 0 var(--spacing-md);
    }
    
    .hero-content {
        gap: var(--spacing-xl);
    }
    
    .hero-title {
        font-size: 3rem;
    }
    
    .paths-grid,
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-lg);
    }
    
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-lg);
    }
    
    /* 关于页面平板适配 */
    .intro-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .intro-stats {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .skills-grid {
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    }
    
    /* 联系页面平板适配 */
    .contact-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }
    
    .contact-form-card,
    .contact-info-card {
        padding: var(--spacing-xl);
    }
    
    .form-row {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .contact-methods {
        grid-template-columns: 1fr;
    }
}

/* 移动设备 (最大768px) */
@media (max-width: 768px) {
    /* 导航栏响应式 */
    .hamburger {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: rgba(15, 23, 42, 0.95);
        backdrop-filter: blur(10px);
        flex-direction: column;
        justify-content: flex-start;
        align-items: center;
        padding-top: var(--spacing-xl);
        transition: left 0.3s ease;
        z-index: 999;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-item {
        width: 100%;
        text-align: center;
        margin-bottom: var(--spacing-md);
    }
    
    .nav-link {
        display: flex;
        justify-content: center;
        padding: var(--spacing-md);
        font-size: 1.1rem;
        width: 80%;
        margin: 0 auto;
        border-radius: var(--radius-lg);
    }
    
    /* 汉堡菜单动画 */
    .hamburger.active .bar:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }
    
    .hamburger.active .bar:nth-child(2) {
        opacity: 0;
    }
    
    .hamburger.active .bar:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -6px);
    }
    
    /* 主要内容区域 */
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: var(--spacing-xl);
        padding: var(--spacing-lg) 0;
    }
    
    .hero-title {
        font-size: 2.5rem;
        line-height: 1.2;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
        margin-bottom: var(--spacing-lg);
    }
    
    .hero-buttons {
        justify-content: center;
        flex-direction: column;
        align-items: center;
        gap: var(--spacing-md);
    }
    
    .btn {
        width: 100%;
        max-width: 280px;
        justify-content: center;
        padding: var(--spacing-md) var(--spacing-lg);
        font-size: 1rem;
    }
    
    /* AI动画区域 */
    .ai-animation {
        height: 250px;
        margin-top: var(--spacing-lg);
    }
    
    .neural-network {
        width: 200px;
        height: 200px;
    }
    
    /* 章节标题 */
    .section-title {
        font-size: 2rem;
        text-align: center;
        margin-bottom: var(--spacing-lg);
    }
    
    .section-subtitle {
        font-size: 1rem;
        text-align: center;
        margin-bottom: var(--spacing-xl);
    }
    
    /* 网格布局 */
    .paths-grid,
    .features-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    /* 卡片样式 */
    .path-card,
    .feature-card,
    .contact-card,
    .intro-card,
    .skills-card,
    .philosophy-card {
        padding: var(--spacing-lg);
        margin-bottom: var(--spacing-md);
    }
    
    /* 联系表单 */
    .contact-form {
        padding: var(--spacing-lg);
    }
    
    .form-group {
        margin-bottom: var(--spacing-md);
    }
    
    .form-input,
    .form-textarea {
        font-size: 1rem;
        padding: var(--spacing-md);
    }
    
    /* 页脚 */
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: var(--spacing-xl);
    }
    
    .footer-section {
        margin-bottom: var(--spacing-lg);
    }
    
    .footer-links {
        justify-content: center;
        flex-wrap: wrap;
    }
    
    .social-links {
        justify-content: center;
    }
}

/* 小屏幕移动设备 (最大480px) */
@media (max-width: 480px) {
    /* 基础间距调整 */
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    /* 导航栏 */
    .nav-container {
        padding: 0 var(--spacing-sm);
    }
    
    .nav-logo {
        font-size: 1.1rem;
    }
    
    /* 英雄区域 */
    .hero-title {
        font-size: 2rem;
        line-height: 1.3;
    }
    
    .hero-subtitle {
        font-size: 1rem;
        line-height: 1.5;
    }
    
    /* 关于页面优化 */
    .about-intro {
        margin-bottom: var(--spacing-lg);
    }
    
    .intro-card {
        padding: var(--spacing-md);
    }
    
    .intro-stats {
        grid-template-columns: repeat(3, 1fr);
        gap: var(--spacing-sm);
        margin-top: var(--spacing-md);
    }
    
    .stat-item {
        text-align: center;
        padding: var(--spacing-sm);
        background: var(--bg-glass);
        border-radius: var(--radius-md);
    }
    
    .stat-number {
        font-size: 1.5rem;
        font-weight: 700;
        color: var(--primary-color);
    }
    
    .stat-label {
        font-size: 0.8rem;
        color: var(--text-muted);
    }
    
    .skills-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .skill-category h3 {
        font-size: 1rem;
        margin-bottom: var(--spacing-sm);
    }
    
    .skill-items {
        display: flex;
        flex-wrap: wrap;
        gap: var(--spacing-xs);
    }
    
    .skill-tag {
        font-size: 0.8rem;
        padding: 0.3rem 0.6rem;
        background: var(--bg-glass);
        border-radius: var(--radius-sm);
        color: var(--text-secondary);
    }
    
    /* 联系页面优化 */
    .contact-form-container,
    .contact-info-container {
        width: 100%;
        margin-bottom: var(--spacing-lg);
    }
    
    .contact-form {
        padding: var(--spacing-md);
    }
    
    .form-row {
        flex-direction: column;
        gap: 0;
    }
    
    .form-group {
        margin-bottom: var(--spacing-sm);
    }
    
    .form-input,
    .form-textarea {
        font-size: 16px; /* 防止iOS缩放 */
        padding: var(--spacing-sm);
    }
    
    .submit-btn {
        width: 100%;
        padding: var(--spacing-md);
        font-size: 1rem;
    }
    
    .contact-methods {
        gap: var(--spacing-md);
    }
    
    .contact-method {
        flex-direction: column;
        text-align: center;
        padding: var(--spacing-md);
        background: var(--bg-glass);
        border-radius: var(--radius-md);
    }
    
    .method-icon {
        margin-bottom: var(--spacing-sm);
    }
    
    .method-content h3 {
        font-size: 1rem;
        margin-bottom: var(--spacing-xs);
    }
    
    .method-desc {
        font-size: 0.8rem;
    }
    
    .btn {
        padding: 0.75rem 1.25rem;
        font-size: 0.9rem;
        max-width: 100%;
    }
    
    /* 章节标题 */
    .section-title {
        font-size: 1.75rem;
    }
    
    .section-subtitle {
        font-size: 0.95rem;
    }
    
    /* 卡片内容 */
    .path-card,
    .feature-card,
    .contact-card,
    .intro-card,
    .skills-card,
    .philosophy-card {
        padding: var(--spacing-md);
    }
    
    .card-header h2,
    .card-header h3 {
        font-size: 1.25rem;
    }
    
    /* 技能标签 */
    .skill-tag {
        font-size: 0.8rem;
        padding: 0.4rem 0.8rem;
    }
    
    /* 统计数据 */
    .stat-number {
        font-size: 1.5rem;
    }
    
    .stat-label {
        font-size: 0.8rem;
    }
    
    /* 联系方式 */
    .contact-methods {
        grid-template-columns: 1fr;
    }
    
    .method-icon {
        width: 50px;
        height: 50px;
    }
    
    .method-icon i {
        font-size: 1.2rem;
    }
    
    /* 表单 */
    .contact-form {
        padding: var(--spacing-md);
    }
    
    .form-row {
        flex-direction: column;
    }
    
    .form-group {
        margin-bottom: var(--spacing-sm);
    }
    
    /* 页脚 */
    .footer-section h3 {
        font-size: 1.1rem;
        margin-bottom: var(--spacing-sm);
    }
    
    .footer-link {
        font-size: 0.9rem;
        padding: 0.4rem 0.8rem;
    }
    
    .social-link {
        width: 40px;
        height: 40px;
        font-size: 1.1rem;
    }
}

/* 超小屏幕设备 (最大360px) */
@media (max-width: 360px) {
    .hero-title {
        font-size: 1.75rem;
    }
    
    .section-title {
        font-size: 1.5rem;
    }
    
    .btn {
        font-size: 0.85rem;
        padding: 0.7rem 1rem;
    }
    
    .path-card,
    .feature-card,
    .contact-card {
        padding: var(--spacing-sm);
    }
}

/* 触控设备优化 */
@media (hover: none) and (pointer: coarse) {
    /* 增大触控目标 */
    .btn,
    .nav-link,
    .social-link,
    .footer-link {
        min-height: 44px;
        min-width: 44px;
    }
    
    /* 移除悬停效果，使用点击效果 */
    .btn:hover,
    .nav-link:hover,
    .path-card:hover,
    .feature-card:hover {
        transform: none;
    }
    
    .btn:active,
    .nav-link:active {
        transform: scale(0.98);
        transition: transform 0.1s ease;
    }
    
    /* 优化表单输入 */
    .form-input,
    .form-textarea {
        font-size: 16px; /* 防止iOS缩放 */
        min-height: 44px;
    }
}

/* 高分辨率屏幕优化 */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
    /* 优化图标和小元素的显示 */
    .nav-logo i,
    .card-header i,
    .method-icon i {
        -webkit-font-smoothing: antialiased;
        -moz-osx-font-smoothing: grayscale;
    }
}

/* 性能优化 */
/* 关键渲染路径优化 */
.hero,
.navbar {
    contain: layout style paint;
}

/* GPU加速优化 */
.skill-card,
.project-card,
.test-button,
.hamburger {
    will-change: transform;
    transform: translateZ(0);
}

/* 字体加载优化 */
@font-face {
    font-family: 'Inter';
    font-display: swap;
    src: local('Inter'), url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');
}

/* 图片懒加载优化 */
img[loading="lazy"] {
    opacity: 0;
    transition: opacity 0.3s;
}

img[loading="lazy"].loaded {
    opacity: 1;
}

/* 减少重绘和回流 */
.skill-progress {
    transform: translateZ(0);
    backface-visibility: hidden;
}

/* 滚动性能优化 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    transform: translateZ(0);
    backface-visibility: hidden;
}

/* 动画性能优化 */
@media (prefers-reduced-motion: no-preference) {
    .skill-card:hover,
    .project-card:hover {
        transform: translateY(-10px) translateZ(0);
    }
}

/* 内容可见性优化 */
.skills,
.projects,
.about-content {
    content-visibility: auto;
    contain-intrinsic-size: 0 500px;
}

/* 预加载关键资源 */
.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    z-index: -1;
    will-change: transform;
}

/* 优化CSS选择器性能 */
.navbar-nav > li > a {
    display: block;
    padding: 1rem 1.5rem;
    color: #e2e8f0;
    text-decoration: none;
    transition: color 0.3s ease;
    font-weight: 500;
}

/* 减少CSS计算复杂度 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* 优化渐变性能 */
.hero {
    background: #0f172a;
    background-image: 
        radial-gradient(circle at 20% 50%, rgba(100, 255, 218, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(59, 130, 246, 0.1) 0%, transparent 50%);
}

/* 优化阴影性能 */
.skill-card,
.project-card {
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    transition: box-shadow 0.3s ease, transform 0.3s ease;
}

.skill-card:hover,
.project-card:hover {
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

/* 横屏模式优化 */
@media (max-height: 500px) and (orientation: landscape) {
    .hero-section {
        padding: var(--spacing-lg) 0;
    }
    
    .hero-content {
        min-height: auto;
        gap: var(--spacing-lg);
    }
    
    .hero-title {
        font-size: 2rem;
        margin-bottom: var(--spacing-sm);
    }
    
    .hero-subtitle {
        margin-bottom: var(--spacing-md);
    }
    
    .ai-animation {
        height: 200px;
    }
}