/* 社交软件官网样式文件
   注意：在生产环境中，请对CSS进行压缩以提高加载速度 */

/* CSS变量定义 - 方便主题维护 */
:root {
    --primary-color: #3498db;
    --primary-dark: #2980b9;
    --secondary-color: #e74c3c;
    --text-primary: #2c3e50;
    --text-secondary: #7f8c8d;
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --border-radius: 10px;
    --box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

/* 全局样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'PingFang SC', 'Microsoft YaHei', -apple-system, BlinkMacSystemFont, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-secondary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 导航栏样式 */
.navbar {
    background-color: #fff;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 15px 0;
}

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

.logo h1 {
    font-size: 24px;
    color: #2c3e50;
    font-weight: 700;
}

.nav-links {
    display: flex;
    gap: 30px;
    align-items: center;
}

.nav-links a {
    color: #34495e;
    text-decoration: none;
    font-size: 16px;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: #3498db;
}

.btn-download {
    background-color: #3498db;
    color: white !important;
    padding: 8px 20px;
    border-radius: 25px;
    font-weight: 600;
    transition: all 0.3s;
}

.btn-download:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
}

.menu-toggle {
    display: none;
    font-size: 24px;
    cursor: pointer;
    color: #34495e;
}

/* 英雄区域样式 */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 150px 0 100px;
    margin-top: 70px;
}

.hero .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
}

.hero-content {
    flex: 1;
    min-width: 300px;
    margin-bottom: 30px;
}

.hero-content h2 {
    font-size: 48px;
    margin-bottom: 20px;
    line-height: 1.2;
}

.hero-content p {
    font-size: 20px;
    margin-bottom: 30px;
    opacity: 0.9;
}

.cta-buttons {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.btn-primary {
    background-color: white;
    color: #3498db;
    padding: 12px 30px;
    border-radius: 25px;
    text-decoration: none;
    font-weight: 600;
    font-size: 16px;
    transition: all 0.3s;
    display: inline-block;
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.btn-secondary {
    background-color: transparent;
    color: white;
    padding: 12px 30px;
    border: 2px solid white;
    border-radius: 25px;
    text-decoration: none;
    font-weight: 600;
    font-size: 16px;
    transition: all 0.3s;
    display: inline-block;
}

.btn-secondary:hover {
    background-color: white;
    color: #3498db;
    transform: translateY(-3px);
}

.hero-image {
    flex: 1;
    min-width: 300px;
    text-align: center;
}

.hero-image img {
    max-width: 100%;
    height: auto;
    border-radius: 10px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
}

/* 通用section样式 */
section {
    padding: 100px 0;
}

.section-title {
    text-align: center;
    font-size: 36px;
    margin-bottom: 60px;
    color: #2c3e50;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 80px;
    height: 4px;
    background-color: #3498db;
    margin: 20px auto 0;
    border-radius: 2px;
}

/* 功能介绍样式 */
.features {
    background-color: white;
}

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

.feature-item {
    text-align: center;
    padding: 30px;
    background-color: #f8f9fa;
    border-radius: 10px;
    transition: all 0.3s;
}

.feature-item:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    width: 80px;
    height: 80px;
    background-color: #3498db;
    color: white;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0 auto 20px;
    font-size: 30px;
}

.feature-item h3 {
    font-size: 20px;
    margin-bottom: 15px;
    color: #2c3e50;
}

.feature-item p {
    color: #7f8c8d;
    font-size: 16px;
}

/* 关于我们样式 */
.about {
    background-color: #f8f9fa;
    text-align: center;
}

.about-content p {
    max-width: 800px;
    margin: 0 auto 20px;
    font-size: 18px;
    color: #555;
    line-height: 1.8;
}

/* 应用截图样式 */
.screenshots {
    background-color: white;
}

.screenshots-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.screenshots-grid img {
    width: 100%;
    height: auto;
    border-radius: 10px;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s;
}

.screenshots-grid img:hover {
    transform: scale(1.05);
}

/* 下载区域样式 */
.download-cta {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 100px 0;
}

.download-cta h2 {
    font-size: 36px;
    margin-bottom: 20px;
}

.download-cta p {
    font-size: 18px;
    margin-bottom: 30px;
    opacity: 0.9;
}

/* 下载页面样式 */
.download-page {
    padding: 120px 0 100px;
    background-color: white;
}

.download-description {
    text-align: center;
    font-size: 18px;
    color: #7f8c8d;
    margin-bottom: 60px;
}

.download-options {
    display: flex;
    justify-content: center;
    gap: 40px;
    flex-wrap: wrap;
    margin-bottom: 80px;
}

.download-card {
    background-color: #f8f9fa;
    border-radius: 15px;
    padding: 40px;
    width: 100%;
    max-width: 350px;
    text-align: center;
    transition: all 0.3s;
    border: 2px solid transparent;
}

.download-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}

.download-card.ios:hover {
    border-color: #000;
}

.download-card.android:hover {
    border-color: #4caf50;
}

.platform-icon {
    font-size: 60px;
    margin-bottom: 20px;
}

.ios .platform-icon {
    color: #000;
}

.android .platform-icon {
    color: #4caf50;
}

.download-card h3 {
    font-size: 24px;
    margin-bottom: 10px;
    color: #2c3e50;
}

.download-card p {
    color: #7f8c8d;
    margin-bottom: 10px;
}

.version-info {
    font-size: 14px;
    color: #95a5a6;
    margin-bottom: 30px;
}

.btn-download-platform {
    display: block;
    padding: 12px;
    margin-bottom: 15px;
    border-radius: 25px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
    font-size: 16px;
}

.ios .btn-download-platform {
    background-color: #000;
    color: white;
}

.ios .btn-download-platform:hover {
    background-color: #333;
    transform: translateY(-3px);
}

.android .btn-download-platform {
    background-color: #4caf50;
    color: white;
}

.android .btn-download-platform:hover {
    background-color: #43a047;
    transform: translateY(-3px);
}

.android .btn-download-platform.apk {
    background-color: #ff9800;
    margin-bottom: 0;
}

.android .btn-download-platform.apk:hover {
    background-color: #f57c00;
}

/* 安装指南样式 */
.download-guide {
    margin-bottom: 80px;
}

.download-guide h3 {
    text-align: center;
    font-size: 28px;
    margin-bottom: 40px;
    color: #2c3e50;
}

.guide-steps {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 20px;
}

.step-item {
    display: flex;
    flex: 1;
    min-width: 250px;
    align-items: flex-start;
}

.step-number {
    width: 50px;
    height: 50px;
    background-color: #3498db;
    color: white;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 24px;
    font-weight: bold;
    margin-right: 20px;
    flex-shrink: 0;
}

.step-content h4 {
    font-size: 20px;
    margin-bottom: 10px;
    color: #2c3e50;
}

.step-content p {
    color: #7f8c8d;
    font-size: 16px;
}

/* 常见问题样式 */
.faq h3 {
    text-align: center;
    font-size: 28px;
    margin-bottom: 40px;
    color: #2c3e50;
}

.faq-item {
    margin-bottom: 20px;
    border-bottom: 1px solid #e0e0e0;
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    cursor: pointer;
    transition: all 0.3s;
}

.faq-question:hover {
    color: #3498db;
}

.faq-question h4 {
    font-size: 18px;
    color: #2c3e50;
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s, padding 0.3s;
}

.faq-answer p {
    padding: 0 0 20px;
    color: #7f8c8d;
}

.faq-item.active .faq-answer {
    max-height: 200px;
}

.faq-item.active .faq-question i {
    transform: rotate(180deg);
}

/* 页脚样式 */
.footer {
    background-color: #2c3e50;
    color: white;
    padding: 60px 0 30px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-info h3 {
    font-size: 24px;
    margin-bottom: 10px;
}

.footer-info p {
    opacity: 0.8;
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.footer-links a {
    color: white;
    text-decoration: none;
    opacity: 0.8;
    transition: all 0.3s;
}

.footer-links a:hover {
    opacity: 1;
    color: #3498db;
}

.footer-social {
    display: flex;
    gap: 20px;
}

.footer-social a {
    color: white;
    font-size: 24px;
    opacity: 0.8;
    transition: all 0.3s;
}

.footer-social a:hover {
    opacity: 1;
    color: #3498db;
    transform: translateY(-3px);
}

.footer-copyright {
    text-align: center;
    opacity: 0.7;
    font-size: 14px;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* 响应式设计 */
@media (max-width: 992px) {
    .hero-content h2 {
        font-size: 40px;
    }
    
    .guide-steps {
        flex-direction: column;
        align-items: center;
    }
    
    .step-item {
        max-width: 500px;
    }
}

@media (max-width: 768px) {
    .nav-links {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background-color: white;
        flex-direction: column;
        padding: 20px 0;
        box-shadow: 0 5px 10px rgba(0, 0, 0, 0.1);
        transform: translateY(-150%);
        transition: transform 0.3s;
        z-index: 999;
    }
    
    .nav-links.active {
        transform: translateY(0);
    }
    
    .menu-toggle {
        display: block;
    }
    
    .hero {
        padding: 100px 0 80px;
    }
    
    .hero-content h2 {
        font-size: 32px;
    }
    
    .cta-buttons {
        justify-content: center;
    }
    
    .footer-content {
        justify-content: center;
        text-align: center;
    }
    
    .footer-links {
        align-items: center;
    }
}

@media (max-width: 576px) {
    .section-title {
        font-size: 28px;
    }
    
    .hero-content h2 {
        font-size: 28px;
    }
    
    .feature-item {
        padding: 20px;
    }
    
    .download-card {
        padding: 30px 20px;
    }
    
    .step-number {
        width: 40px;
        height: 40px;
        font-size: 20px;
    }
}