/* CSS 自定义属性 (CSS Variables) */
:root {
    /* 主色调 */
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --secondary-color: #10b981;
    --accent-color: #f59e0b;
    
    /* 中性色 */
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    
    /* 边框和分割线 */
    --border-color: #e5e7eb;
    --border-light: #f3f4f6;
    
    /* 阴影 */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    /* 字体 */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;
    
    /* 间距 */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    /* 圆角 */
    --border-radius-sm: 0.25rem;
    --border-radius-md: 0.375rem;
    --border-radius-lg: 0.5rem;
    --border-radius-xl: 0.75rem;
    --border-radius-2xl: 1rem;
    
    /* 过渡动画 */
    --transition-fast: 0.15s ease-in-out;
    --transition-normal: 0.3s ease-in-out;
    --transition-slow: 0.5s ease-in-out;
    
    /* 容器最大宽度 */
    --container-max-width: 1200px;
    
    /* 渐变色 */
    --gradient-primary: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-light) 100%);
    --gradient-secondary: linear-gradient(135deg, var(--secondary-color) 0%, #34d399 100%);
    --gradient-hero: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

/* 全局重置和基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px;
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
}

/* 容器布局 */
.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
    .container {
        padding: 0 var(--spacing-xl);
    }
}

/* 通用按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    border: none;
    border-radius: var(--border-radius-lg);
    font-weight: 500;
    text-decoration: none;
    transition: all var(--transition-normal);
    cursor: pointer;
    font-size: var(--font-size-base);
    line-height: 1;
}

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

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

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

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

.btn-full {
    width: 100%;
    justify-content: center;
}

.btn-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border: none;
    border-radius: 50%;
    background: white;
    color: var(--primary-color);
    cursor: pointer;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-md);
}

.btn-icon:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-lg);
}

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-light);
    transition: all var(--transition-normal);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--shadow-md);
}

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

.logo-text {
    font-size: var(--font-size-xl);
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

.nav-link {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition-normal);
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: width var(--transition-normal);
}

.nav-link:hover::after {
    width: 100%;
}

/* 汉堡菜单 */
.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

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

/* 响应式导航 */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: white;
        flex-direction: column;
        justify-content: start;
        align-items: center;
        padding-top: var(--spacing-3xl);
        transition: left var(--transition-normal);
        box-shadow: var(--shadow-lg);
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-item {
        margin: var(--spacing-md) 0;
    }
    
    .hamburger {
        display: flex;
    }
    
    .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);
    }
}

/* 首页/Hero区域 */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-hero);
    z-index: -2;
}

.hero-background::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="1"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    z-index: -1;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-3xl);
    align-items: center;
    width: 100%;
}

@media (min-width: 768px) {
    .hero-content {
        grid-template-columns: 1fr 1fr;
    }
}

.hero-text {
    color: white;
}

.hero-title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-lg);
}

@media (min-width: 768px) {
    .hero-title {
        font-size: var(--font-size-5xl);
    }
}

.title-line {
    display: block;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease-out forwards;
}

.title-line:nth-child(2) {
    animation-delay: 0.2s;
}

.hero-subtitle {
    font-size: var(--font-size-lg);
    opacity: 0.9;
    margin-bottom: var(--spacing-xl);
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease-out 0.4s forwards;
}

.hero-stats {
    display: flex;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease-out 0.6s forwards;
}

.stat {
    text-align: center;
}

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

.stat-label {
    font-size: var(--font-size-sm);
    opacity: 0.8;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease-out 0.8s forwards;
}

/* 浮动卡片动画 */
.hero-visual {
    position: relative;
    height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.floating-cards {
    position: relative;
    width: 300px;
    height: 300px;
}

.card {
    position: absolute;
    background: white;
    border-radius: var(--border-radius-xl);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-xl);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
    animation: float 6s ease-in-out infinite;
    width: 120px;
    height: 100px;
    justify-content: center;
}

.card i {
    font-size: var(--font-size-2xl);
    color: var(--primary-color);
}

.card span {
    font-weight: 500;
    color: var(--text-primary);
    white-space: nowrap;
}

.card-1 {
    top: 5%;
    left: 5%;
    animation-delay: 0s;
}

.card-2 {
    top: 15%;
    right: 5%;
    animation-delay: 1.5s;
}

.card-3 {
    bottom: 25%;
    left: 5%;
    animation-delay: 3s;
}

.card-4 {
    bottom: 5%;
    right: 5%;
    animation-delay: 4.5s;
}

/* 响应式优化浮动卡片 */
@media (max-width: 768px) {
    .floating-cards {
        width: 250px;
        height: 250px;
    }
    
    .card {
        padding: var(--spacing-md);
        width: 100px;
        height: 80px;
    }
    
    .card i {
        font-size: var(--font-size-xl);
    }
    
    .card span {
        font-size: var(--font-size-sm);
    }
    
    .card-1 {
        top: 0%;
        left: 0%;
    }

    .card-2 {
        top: 20%;
        right: 0%;
    }

    .card-3 {
        bottom: 30%;
        left: 0%;
    }

    .card-4 {
        bottom: 0%;
        right: 0%;
    }
}

/* 滚动指示器 */
.scroll-indicator {
    position: absolute;
    bottom: var(--spacing-xl);
    left: 50%;
    transform: translateX(-50%);
    color: white;
    animation: bounce 2s infinite;
}

.scroll-arrow {
    width: 24px;
    height: 24px;
    border-right: 2px solid white;
    border-bottom: 2px solid white;
    transform: rotate(45deg);
}

/* 区域通用样式 */
section {
    padding: var(--spacing-3xl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-3xl);
}

.section-tag {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-tertiary);
    color: var(--primary-color);
    font-size: var(--font-size-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-radius: var(--border-radius-md);
    margin-bottom: var(--spacing-md);
}

.section-title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.section-subtitle {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* 技能区域 */
.skills {
    background: var(--bg-secondary);
}

.skills-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
}

@media (min-width: 768px) {
    .skills-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .skills-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.skill-category {
    background: white;
    border-radius: var(--border-radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-normal);
}

.skill-category:hover {
    transform: translateY(-5px);
}

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

.category-header i {
    font-size: var(--font-size-2xl);
    color: var(--primary-color);
}

.category-header h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-primary);
}

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

.skill-item {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.skill-name {
    font-weight: 500;
    color: var(--text-primary);
}

.skill-bar {
    height: 8px;
    background: var(--bg-tertiary);
    border-radius: var(--border-radius-md);
    overflow: hidden;
}

.skill-progress {
    height: 100%;
    background: var(--gradient-primary);
    border-radius: var(--border-radius-md);
    width: 0;
    transition: width 1s ease-out;
}

/* 服务区域 */
.services-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
}

@media (min-width: 768px) {
    .services-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .services-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.service-card {
    background: white;
    border-radius: var(--border-radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
    border: 1px solid var(--border-light);
}

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

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

.service-icon i {
    font-size: var(--font-size-2xl);
    color: white;
}

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

.service-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
}

.service-features {
    list-style: none;
}

.service-features li {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
}

.service-features li::before {
    content: '✓';
    color: var(--secondary-color);
    font-weight: bold;
    width: 16px;
    height: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(16, 185, 129, 0.1);
    border-radius: 50%;
    flex-shrink: 0;
}

/* 应用领域区域 */
.applications {
    background: var(--bg-secondary);
}

.applications-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
}

@media (min-width: 768px) {
    .applications-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .applications-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.application-item {
    background: white;
    border-radius: var(--border-radius-xl);
    padding: var(--spacing-xl);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
    cursor: pointer;
}

.application-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

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

.app-icon i {
    font-size: var(--font-size-3xl);
    color: white;
}

.application-item h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.application-item p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
}

.app-tags {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    flex-wrap: wrap;
}

.tag {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--bg-tertiary);
    color: var(--primary-color);
    font-size: var(--font-size-xs);
    font-weight: 500;
    border-radius: var(--border-radius-md);
}

/* 项目案例区域 */
.projects-filter {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-3xl);
    flex-wrap: wrap;
}

.filter-btn {
    padding: var(--spacing-md) var(--spacing-xl);
    border: 2px solid var(--border-color);
    background: white;
    color: var(--text-secondary);
    border-radius: var(--border-radius-lg);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-normal);
}

.filter-btn:hover,
.filter-btn.active {
    border-color: var(--primary-color);
    background: var(--primary-color);
    color: white;
}

.projects-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
}

@media (min-width: 768px) {
    .projects-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .projects-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.project-card {
    background: white;
    border-radius: var(--border-radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.project-image {
    position: relative;
    height: 200px;
    overflow: hidden;
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-normal);
}

.project-card:hover .project-image img {
    transform: scale(1.05);
}

.project-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.project-card:hover .project-overlay {
    opacity: 1;
}

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

.project-content {
    padding: var(--spacing-xl);
}

.project-category {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--bg-tertiary);
    color: var(--primary-color);
    font-size: var(--font-size-xs);
    font-weight: 600;
    text-transform: uppercase;
    border-radius: var(--border-radius-md);
    margin-bottom: var(--spacing-md);
}

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

.project-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
}

.project-tech {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.tech-tag {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-md);
    background: rgba(37, 99, 235, 0.1);
    color: var(--primary-color);
    font-size: var(--font-size-xs);
    font-weight: 500;
    border-radius: var(--border-radius-md);
}

/* 联系区域 */
.contact {
    background: var(--bg-secondary);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-3xl);
}

@media (min-width: 1024px) {
    .contact-content {
        grid-template-columns: 1fr 1fr;
    }
}

.contact-info h3 {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.contact-info > p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.6;
}

.contact-methods {
    margin-bottom: var(--spacing-xl);
}

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

.method-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    border-radius: var(--border-radius-xl);
}

.method-icon i {
    font-size: var(--font-size-xl);
    color: white;
}

.method-info h4 {
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.method-info p {
    color: var(--text-secondary);
}

.contact-availability h4 {
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.availability-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: var(--spacing-sm);
}

.day {
    color: var(--text-secondary);
}

.time {
    color: var(--text-primary);
    font-weight: 500;
}

/* 表单样式 */
.contact-form {
    background: white;
    border-radius: var(--border-radius-xl);
    padding: var(--spacing-3xl);
    box-shadow: var(--shadow-lg);
}

.form-group {
    margin-bottom: var(--spacing-lg);
}

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

@media (min-width: 768px) {
    .form-row {
        grid-template-columns: 1fr 1fr;
    }
}

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

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    font-size: var(--font-size-base);
    transition: border-color var(--transition-normal);
    background: white;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

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

/* 页脚 */
.footer {
    background: var(--text-primary);
    color: white;
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

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

@media (min-width: 768px) {
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .footer-content {
        grid-template-columns: repeat(4, 1fr);
    }
}

.footer-section h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.footer-section p {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.6;
    margin-bottom: var(--spacing-md);
}

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

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    color: white;
    text-decoration: none;
    transition: all var(--transition-normal);
}

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

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: var(--spacing-sm);
}

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color var(--transition-normal);
}

.footer-links a:hover {
    color: white;
}

.contact-info-footer p {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
    color: rgba(255, 255, 255, 0.8);
}

.contact-info-footer i {
    width: 16px;
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-xl);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.6);
}

/* 回到顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    border: none;
    border-radius: 50%;
    color: white;
    cursor: pointer;
    transition: all var(--transition-normal);
    opacity: 0;
    visibility: hidden;
    z-index: 1000;
    box-shadow: var(--shadow-lg);
}

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

.back-to-top:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-xl);
}

/* 动画关键帧 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateX(-50%) translateY(0);
    }
    40% {
        transform: translateX(-50%) translateY(-10px);
    }
    60% {
        transform: translateX(-50%) translateY(-5px);
    }
}

/* 加载动画 */
@keyframes pulse {
    0% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
    100% {
        opacity: 1;
    }
}

/* 工具类 */
.text-center {
    text-align: center;
}

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

.text-right {
    text-align: right;
}

.hidden {
    display: none;
}

.visible {
    display: block;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* 响应式工具类 */
@media (max-width: 767px) {
    .hide-mobile {
        display: none;
    }
}

@media (min-width: 768px) {
    .hide-desktop {
        display: none;
    }
}

/* 打印样式 */
@media print {
    .navbar,
    .back-to-top {
        display: none;
    }
    
    .hero {
        height: auto;
        min-height: auto;
    }
    
    section {
        break-inside: avoid;
    }
}