:root {
    --primary-color: #007AFF;
    --secondary-color: #5856D6;
    --accent-color: #34C759;
    --text-color: #333;
    --light-gray: #f5f5f5;
    --medium-gray: #e5e5e5;
    --dark-gray: #333;
    --white: #fff;
    --transition: all 0.3s ease;
    --border-radius: 12px;
    --shadow: 0 4px 20px rgba(0,0,0,0.1);
    --section-padding: 80px 20px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    overflow-x: hidden;
}

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    z-index: 1000;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: var(--text-color);
    text-decoration: none;
    transition: var(--transition);
    font-weight: 500;
}

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

/* 语言切换过渡动画 */
.language-transition {
    transition: all 0.3s ease;
}

.language-transition * {
    transition: all 0.3s ease;
}

/* 语言切换器样式 */
.language-switcher {
    position: relative;
    margin-left: 20px;
}

.lang-btn {
    background: transparent;
    border: 1px solid var(--primary-color);
    color: var(--primary-color);
    padding: 8px 15px;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
    min-width: 120px;
    justify-content: space-between;
}

.lang-btn:hover {
    background: var(--primary-color);
    color: var(--white);
}

.lang-btn .lang-arrow {
    font-size: 0.8em;
    transition: transform 0.3s ease;
}

.lang-dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--white);
    border: 1px solid var(--primary-color);
    border-radius: 10px;
    margin-top: 5px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    z-index: 1000;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.language-switcher:hover .lang-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.language-switcher:hover .lang-btn .lang-arrow {
    transform: rotate(180deg);
}

.lang-option {
    padding: 10px 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.lang-option:hover {
    background: var(--primary-color);
    color: var(--white);
}

.lang-option.active {
    background: var(--primary-color);
    color: var(--white);
}

/* 头部区域 */
.header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
    padding: 120px 20px 80px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('../assets/pattern.svg') repeat;
    opacity: 0.1;
}

.header h1 {
    font-size: 3.5em;
    margin-bottom: 10px;
    animation: fadeInUp 1s ease;
}

.header .subtitle {
    font-size: 1.5em;
    margin-bottom: 20px;
    opacity: 0.9;
    animation: fadeInUp 1s ease 0.1s;
    animation-fill-mode: forwards;
}

.header p {
    font-size: 1.2em;
    max-width: 800px;
    margin: 0 auto 40px;
    animation: fadeInUp 1s ease 0.2s;
    opacity: 0;
    animation-fill-mode: forwards;
}

.header-actions {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: 40px;
    animation: fadeInUp 1s ease 0.3s;
    opacity: 0;
    animation-fill-mode: forwards;
}

.btn-primary, .btn-secondary {
    display: inline-block;
    padding: 15px 30px;
    border-radius: 30px;
    text-decoration: none;
    font-weight: bold;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--white);
    color: var(--primary-color);
}

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

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

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

/* 核心功能区域 */
.core-features {
    padding: var(--section-padding);
    max-width: 1400px;
    margin: 0 auto;
}

.core-features h2 {
    text-align: center;
    font-size: 2.5em;
    margin-bottom: 60px;
    color: var(--primary-color);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 40px;
}

.feature-card {
    background: var(--white);
    padding: 40px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 8px 30px rgba(0,0,0,0.15);
}

.feature-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.feature-card h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.3em;
}

.feature-card p {
    margin-bottom: 20px;
    color: var(--text-color);
}

.feature-card ul {
    list-style: none;
    padding: 0;
}

.feature-card li {
    padding: 8px 0;
    padding-left: 20px;
    position: relative;
    color: var(--text-color);
}

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

/* 使用场景区域 */
.use-scenarios {
    background: var(--light-gray);
    padding: var(--section-padding);
}

.use-scenarios h2 {
    text-align: center;
    font-size: 2.5em;
    margin-bottom: 60px;
    color: var(--primary-color);
}

.scenarios-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 40px;
    max-width: 1200px;
    margin: 0 auto;
}

.scenario-card {
    background: var(--white);
    padding: 40px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
    text-align: center;
}

.scenario-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(0,0,0,0.15);
}

.scenario-icon {
    font-size: 2.5rem;
    color: var(--secondary-color);
    margin-bottom: 20px;
}

.scenario-card h3 {
    color: var(--primary-color);
    margin-bottom: 20px;
    font-size: 1.3em;
}

.scenario-content h4 {
    color: var(--secondary-color);
    margin: 20px 0 10px;
    font-size: 1.1em;
}

.scenario-content p {
    color: var(--text-color);
    margin-bottom: 15px;
    text-align: left;
}

/* 技术特性区域 */
.tech-features {
    padding: var(--section-padding);
    max-width: 1200px;
    margin: 0 auto;
}

.tech-features h2 {
    text-align: center;
    font-size: 2.5em;
    margin-bottom: 60px;
    color: var(--primary-color);
}

.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: 40px;
}

.tech-card {
    background: var(--white);
    padding: 40px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.tech-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(0,0,0,0.15);
}

.tech-icon {
    font-size: 2.5rem;
    color: var(--accent-color);
    margin-bottom: 20px;
}

.tech-card h3 {
    color: var(--primary-color);
    margin-bottom: 20px;
    font-size: 1.3em;
}

.tech-card ul {
    list-style: none;
    padding: 0;
}

.tech-card li {
    padding: 10px 0;
    padding-left: 25px;
    position: relative;
    color: var(--text-color);
}

.tech-card li::before {
    content: '⚡';
    position: absolute;
    left: 0;
    color: var(--accent-color);
}

/* 优势区域 */
.advantages {
    background: var(--light-gray);
    padding: var(--section-padding);
}

.advantages h2 {
    text-align: center;
    font-size: 2.5em;
    margin-bottom: 60px;
    color: var(--primary-color);
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    max-width: 1200px;
    margin: 0 auto;
}

.advantage-card {
    background: var(--white);
    padding: 30px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    text-align: center;
    transition: var(--transition);
}

.advantage-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(0,0,0,0.15);
}

.advantage-icon {
    font-size: 2rem;
    color: var(--secondary-color);
    margin-bottom: 20px;
}

.advantage-card h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.2em;
}

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

/* 演示区域 */
.demo-section {
    padding: var(--section-padding);
    max-width: 1200px;
    margin: 0 auto;
}

.demo-section h2 {
    text-align: center;
    font-size: 2.5em;
    margin-bottom: 60px;
    color: var(--primary-color);
}

.demo-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.step {
    text-align: center;
    padding: 30px 20px;
    background: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.step:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(0,0,0,0.15);
}

.step-number {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: var(--primary-color);
    color: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: bold;
    margin: 0 auto 20px;
}

.step h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.2em;
}

.step p {
    color: var(--text-color);
}

/* 下载区域 */
.download-section {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
    padding: var(--section-padding);
    text-align: center;
    position: relative;
}

.download-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('../assets/pattern.svg') repeat;
    opacity: 0.1;
}

.download-section h2 {
    font-size: 2.5em;
    margin-bottom: 20px;
}

.download-section p {
    font-size: 1.2em;
    margin-bottom: 20px;
    opacity: 0.9;
}

.download-btn {
    display: inline-block;
    background: var(--white);
    color: var(--primary-color);
    padding: 15px 30px;
    border-radius: 30px;
    text-decoration: none;
    font-weight: bold;
    margin: 20px 0;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.download-btn::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255,255,255,0.2);
    transform: translateX(-100%);
    transition: transform 0.6s ease;
}

.download-btn:hover {
    background: var(--accent-color);
    color: var(--white);
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.2);
}

.download-btn:hover::after {
    transform: translateX(100%);
}

.download-note {
    font-size: 0.9em;
    opacity: 0.8;
    font-style: italic;
}

/* 系统要求 */
.requirements {
    max-width: 800px;
    margin: 80px auto;
    padding: 0 20px;
}

.requirements h2 {
    text-align: center;
    margin-bottom: 40px;
    font-size: 2.5em;
    color: var(--primary-color);
}

.requirements ul {
    list-style: none;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.requirements li {
    background: var(--light-gray);
    padding: 20px;
    border-radius: var(--border-radius);
    display: flex;
    align-items: center;
    gap: 15px;
    transition: var(--transition);
}

.requirements li:hover {
    background: var(--white);
    box-shadow: var(--shadow);
}

.requirements li i {
    color: var(--accent-color);
    font-size: 1.2rem;
}

/* 页脚 */
footer {
    background: var(--dark-gray);
    color: var(--white);
    padding: 40px 20px 20px;
    text-align: center;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 30px;
}

.footer-section h3 {
    margin-bottom: 20px;
    color: var(--primary-color);
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-top: 20px;
}

.social-links a {
    color: var(--white);
    font-size: 1.5rem;
    transition: var(--transition);
}

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

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.icp-info {
    font-size: 0.9em;
    opacity: 0.7;
    color: var(--white);
}

/* 动画 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 可访问性优化 */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* 焦点样式优化 */
*:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* 跳过链接 */
.skip-link {
    position: absolute;
    top: -40px;
    left: 6px;
    background: var(--primary-color);
    color: var(--white);
    padding: 8px;
    text-decoration: none;
    border-radius: 4px;
    z-index: 1001;
}

.skip-link:focus {
    top: 6px;
}

/* 高对比度模式支持 */
@media (prefers-contrast: high) {
    :root {
        --text-color: #000;
        --light-gray: #fff;
        --medium-gray: #ccc;
    }
}

/* 打印样式 */
@media print {
    .navbar,
    .header-actions,
    .language-switcher,
    .download-btn {
        display: none !important;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.4;
    }
    
    .header {
        background: none !important;
        color: #000 !important;
        padding: 20px 0;
    }
    
    .feature-card,
    .scenario-card,
    .tech-card,
    .advantage-card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ccc;
    }
}

/* 响应式设计优化 */
@media (max-width: 1024px) {
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .tech-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    :root {
        --section-padding: 60px 20px;
    }
    
    .navbar {
        padding: 1rem;
    }
    
    .nav-links {
        display: none;
    }
    
    .header h1 {
        font-size: 2.5em;
    }
    
    .header .subtitle {
        font-size: 1.2em;
    }
    
    .header p {
        font-size: 1em;
    }
    
    .header-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .features-grid,
    .scenarios-grid,
    .advantages-grid,
    .demo-steps {
        grid-template-columns: 1fr;
    }
    
    .language-switcher {
        margin-left: 10px;
    }
    
    .lang-btn {
        padding: 6px 12px;
        min-width: 100px;
    }
    
    .core-features h2,
    .use-scenarios h2,
    .tech-features h2,
    .advantages h2,
    .demo-section h2,
    .download-section h2,
    .requirements h2 {
        font-size: 2em;
    }
    
    .footer-bottom {
        gap: 15px;
    }
    
    .icp-info {
        font-size: 0.8em;
    }
}