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

:root {
    --primary-color: #4f46e5;
    --primary-dark: #4338ca;
    --secondary-color: #6366f1;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-light: #f9fafb;
    --bg-white: #ffffff;
    --border-color: #e5e7eb;
    --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);
}

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

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

/* 导航栏 */
.navbar {
    background: var(--bg-white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 1rem 0;
}

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

.nav-brand h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: color 0.3s;
}

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


/* 可切换内容区域 */
.toggleable-section-content {
    transition: opacity 0.3s ease, display 0.3s ease;
}

.toggleable-section-content.hidden {
    display: none !important;
}

.toggleable-section-content.visible {
    display: block !important;
}

/* 导航栏中可切换的链接默认隐藏（通过JavaScript控制） */
.nav-menu li.toggleable-nav-item {
    display: none;
}

.nav-menu li.toggleable-nav-item.visible {
    display: list-item;
}

/* 语言切换 */
.nav-lang-wrap {
    position: relative;
    list-style: none;
}
.lang-switcher-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.45rem 0.75rem;
    background: var(--bg-light, #f3f4f6);
    border: 1px solid transparent;
    border-radius: 9999px;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-primary);
    cursor: pointer;
    transition: background 0.2s, border-color 0.2s, color 0.2s;
}
.lang-switcher-btn:hover {
    background: var(--border-color, #e5e7eb);
    color: var(--primary-color);
}
.lang-switcher-btn[aria-expanded="true"] {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}
.lang-switcher-btn[aria-expanded="true"] .lang-switcher-icon,
.lang-switcher-btn[aria-expanded="true"] .lang-switcher-chevron {
    color: inherit;
}
.lang-switcher-icon {
    display: flex;
    color: var(--text-secondary);
}
.lang-switcher-current {
    min-width: 4.5rem;
    text-align: left;
}
.lang-switcher-chevron {
    display: flex;
    color: var(--text-secondary);
    transition: transform 0.2s;
}
.lang-switcher-btn[aria-expanded="true"] .lang-switcher-chevron {
    transform: rotate(180deg);
}
.lang-switcher-dropdown {
    position: absolute;
    top: calc(100% + 6px);
    right: 0;
    min-width: 10rem;
    padding: 0.25rem;
    background: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.12);
    list-style: none;
    z-index: 100;
}
.lang-switcher-dropdown[hidden] {
    display: none !important;
}
.lang-switcher-dropdown button {
    display: flex;
    align-items: center;
    width: 100%;
    padding: 0.5rem 0.75rem;
    border: none;
    border-radius: 8px;
    background: none;
    text-align: left;
    font-size: 0.875rem;
    color: var(--text-primary);
    cursor: pointer;
    transition: background 0.15s;
}
.lang-switcher-dropdown button:hover {
    background: var(--bg-light, #f3f4f6);
}
.lang-switcher-dropdown button:focus {
    outline: none;
    background: var(--bg-light);
}

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

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    transition: all 0.3s;
}

/* Hero区域 */
.hero {
    padding: 80px 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
    display: inline-block;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

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

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

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

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

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

/* 产品展示图 */
.product-showcase {
    position: relative;
    width: 100%;
    max-width: 700px;
    height: 500px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

/* 设备容器 */
.devices-container {
    display: flex;
    gap: 1.5rem;
    align-items: flex-end;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 2rem;
}

/* 设备通用样式 */
.device {
    position: relative;
    animation: float 3s ease-in-out infinite;
}

.device:nth-child(1) {
    animation-delay: 0s;
}

.device:nth-child(2) {
    animation-delay: 0.5s;
}

.device:nth-child(3) {
    animation-delay: 1s;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-10px);
    }
}

.device-frame {
    background: linear-gradient(145deg, #2d2d2d, #1a1a1a);
    border-radius: 20px;
    padding: 8px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    position: relative;
}

.device-android .device-frame {
    width: 140px;
    height: 280px;
}

.device-ios .device-frame {
    width: 140px;
    height: 280px;
    border-radius: 25px;
}

.device-web .device-frame {
    width: 200px;
    height: 150px;
    border-radius: 8px;
}

.device-screen {
    width: 100%;
    height: 100%;
    background: #ffffff;
    border-radius: 12px;
    overflow: hidden;
    position: relative;
}

.device-ios .device-screen {
    border-radius: 17px;
}

.device-web .device-screen {
    border-radius: 4px;
}

.device-label {
    text-align: center;
    margin-top: 10px;
    font-size: 0.875rem;
    font-weight: 600;
    color: rgba(255, 255, 255, 0.9);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

/* 聊天界面样式 */
.chat-interface {
    height: 100%;
    display: flex;
    flex-direction: column;
    background: #f5f5f5;
}

.chat-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.avatar-small {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
}

.header-info {
    flex: 1;
}

.name-line {
    height: 8px;
    width: 60px;
    background: rgba(255, 255, 255, 0.8);
    border-radius: 4px;
    margin-bottom: 4px;
}

.status-line {
    height: 6px;
    width: 40px;
    background: rgba(255, 255, 255, 0.5);
    border-radius: 3px;
}

.chat-messages {
    flex: 1;
    padding: 12px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    overflow: hidden;
}

.message {
    display: flex;
    animation: messageSlide 0.5s ease-out;
}

.message:nth-child(1) {
    animation-delay: 0.2s;
    animation-fill-mode: both;
}

.message:nth-child(2) {
    animation-delay: 0.4s;
    animation-fill-mode: both;
}

.message:nth-child(3) {
    animation-delay: 0.6s;
    animation-fill-mode: both;
}

@keyframes messageSlide {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.message-received {
    justify-content: flex-start;
}

.message-sent {
    justify-content: flex-end;
}

.message-bubble {
    max-width: 80%;
    padding: 8px 12px;
    border-radius: 12px;
    font-size: 10px;
    line-height: 1.4;
}

.bubble-received {
    background: #ffffff;
    color: #333;
    border-bottom-left-radius: 4px;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
}

.bubble-sent {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-bottom-right-radius: 4px;
}

.image-bubble {
    width: 60px;
    height: 60px;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #e0e0e0;
    font-size: 20px;
}

/* Web界面样式 */
.web-interface {
    height: 100%;
    display: flex;
    flex-direction: column;
    background: #ffffff;
}

.web-header {
    background: #f8f9fa;
    padding: 8px;
    border-bottom: 1px solid #e0e0e0;
}

.web-tabs {
    display: flex;
    gap: 6px;
}

.tab {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: #ddd;
}

.tab.active {
    background: #667eea;
}

.web-content {
    flex: 1;
    display: flex;
}

.sidebar {
    width: 50px;
    background: #f8f9fa;
    border-right: 1px solid #e0e0e0;
    padding: 8px;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.sidebar-item {
    height: 30px;
    background: #e0e0e0;
    border-radius: 4px;
}

.sidebar-item.active {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.main-content {
    flex: 1;
    padding: 12px;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.content-line {
    height: 8px;
    background: #e0e0e0;
    border-radius: 4px;
    width: 100%;
}

.content-line.short {
    width: 60%;
}

/* 功能图标 */
.features-icons {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 1rem;
}

.feature-icon {
    width: 50px;
    height: 50px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    cursor: pointer;
    transition: all 0.3s;
    backdrop-filter: blur(10px);
    border: 2px solid rgba(255, 255, 255, 0.3);
    animation: iconPulse 2s ease-in-out infinite;
}

.feature-icon:nth-child(1) {
    animation-delay: 0s;
}

.feature-icon:nth-child(2) {
    animation-delay: 0.3s;
}

.feature-icon:nth-child(3) {
    animation-delay: 0.6s;
}

.feature-icon:nth-child(4) {
    animation-delay: 0.9s;
}

.feature-icon svg {
    width: 24px;
    height: 24px;
}

.feature-icon:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-5px) scale(1.1);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    animation: none;
}

@keyframes iconPulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.7;
    }
}

/* 响应式调整 */
@media (max-width: 768px) {
    .devices-container {
        gap: 1rem;
    }
    
    .device-android .device-frame,
    .device-ios .device-frame {
        width: 100px;
        height: 200px;
    }
    
    .device-web .device-frame {
        width: 150px;
        height: 110px;
    }
    
    .features-icons {
        gap: 1rem;
    }
    
    .feature-icon {
        width: 40px;
        height: 40px;
    }
    
    .feature-icon svg {
        width: 20px;
        height: 20px;
    }
}

/* 产品介绍 */
.about {
    padding: 80px 0;
    background: var(--bg-light);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.about-card {
    background: var(--bg-white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s, box-shadow 0.3s;
}

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

.card-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.about-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.about-card p {
    color: var(--text-secondary);
}

/* 功能特性 */
.features {
    padding: 80px 0;
    background: var(--bg-white);
}

.features-tabs {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.tab-btn {
    padding: 12px 24px;
    border: 2px solid var(--border-color);
    background: var(--bg-white);
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.3s;
    color: var(--text-primary);
}

.tab-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

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

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.feature-item {
    background: var(--bg-light);
    padding: 1.5rem;
    border-radius: 12px;
    border-left: 4px solid var(--primary-color);
}

.feature-item h4 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.feature-item ul {
    list-style: none;
}

.feature-item li {
    padding: 0.5rem 0;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
}

.feature-item li:last-child {
    border-bottom: none;
}

/* 多平台支持 */
.platforms {
    padding: 80px 0;
    background: var(--bg-light);
}

.platforms-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.platform-card {
    background: var(--bg-white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: transform 0.3s;
}

.platform-card:hover {
    transform: translateY(-5px);
}

.platform-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.platform-card h3 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.platform-version {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

.platform-features {
    list-style: none;
    text-align: left;
}

.platform-features li {
    padding: 0.5rem 0;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
}

.platform-features li:last-child {
    border-bottom: none;
}

/* API文档 */
.api {
    padding: 80px 0;
    background: var(--bg-white);
}

.api-intro {
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.api-categories {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.api-category {
    background: var(--bg-light);
    padding: 2rem;
    border-radius: 12px;
}

.api-category h3 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.api-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.api-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    background: var(--bg-white);
    padding: 1rem;
    border-radius: 8px;
    border-left: 4px solid var(--primary-color);
}

.api-method {
    padding: 4px 12px;
    border-radius: 4px;
    font-weight: 600;
    font-size: 0.875rem;
    min-width: 60px;
    text-align: center;
}

.api-method.get {
    background: #10b981;
    color: white;
}

.api-method.post {
    background: #3b82f6;
    color: white;
}

.api-method.put {
    background: #f59e0b;
    color: white;
}

.api-method.delete {
    background: #ef4444;
    color: white;
}

.api-item code {
    font-family: 'Courier New', monospace;
    background: var(--bg-light);
    padding: 4px 8px;
    border-radius: 4px;
    color: var(--primary-color);
    font-weight: 600;
    flex: 1;
}

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

.api-note {
    margin-top: 3rem;
    padding: 1.5rem;
    background: #fef3c7;
    border-left: 4px solid #f59e0b;
    border-radius: 8px;
}

.api-note a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
}

.api-note a:hover {
    text-decoration: underline;
}

/* 运营经验优势 */
.advantages {
    padding: 80px 0;
    background: var(--bg-white);
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 3rem;
    margin-top: 3rem;
}

.advantage-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    padding: 3rem;
    border-radius: 16px;
    color: white;
    box-shadow: var(--shadow-lg);
    transition: transform 0.3s, box-shadow 0.3s;
}

.advantage-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.2);
}

.advantage-icon {
    font-size: 4rem;
    margin-bottom: 1.5rem;
    display: inline-block;
}

.advantage-card h3 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.advantage-card > p {
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    opacity: 0.95;
    line-height: 1.8;
}

.advantage-list {
    list-style: none;
    margin-top: 1.5rem;
}

.advantage-list li {
    padding: 0.75rem 0;
    font-size: 1rem;
    opacity: 0.9;
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

.advantage-list li:last-child {
    border-bottom: none;
}

/* 产品演示 */
.demo {
    padding: 80px 0;
    background: var(--bg-light);
}

.demo-intro {
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.video-section {
    margin-bottom: 4rem;
}

.video-section:last-child {
    margin-bottom: 0;
}

.video-section-title {
    font-size: 1.75rem;
    font-weight: 600;
    margin-bottom: 2rem;
    color: var(--text-primary);
    padding-bottom: 1rem;
    border-bottom: 3px solid var(--primary-color);
}

.videos-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.video-item {
    background: var(--bg-white);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: transform 0.3s, box-shadow 0.3s;
}

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

.video-wrapper {
    position: relative;
    width: 100%;
    padding-top: 56.25%; /* 16:9 aspect ratio */
    background: #000;
    overflow: hidden;
}

.video-wrapper video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    max-width: 480px;
    object-fit: contain;
    background: #000;
}

.video-wrapper video::-webkit-media-controls-panel {
    background-color: rgba(0, 0, 0, 0.7);
}

.video-wrapper video::-webkit-media-controls-play-button {
    background-color: var(--primary-color);
    border-radius: 50%;
}

/* 手机尺寸视频样式 */
.videos-grid-mobile {
    grid-template-columns: repeat(auto-fit, minmax(200px, 280px));
    gap: 1.5rem;
    justify-content: center;
}

.video-item-mobile {
    max-width: 280px;
    width: 100%;
    display: flex;
    flex-direction: column;
}

.video-wrapper-mobile {
    width: 100%;
    max-width: 280px;
    aspect-ratio: 9 / 16; /* 手机屏幕比例 9:16 */
    background: #000;
    border-radius: 20px;
    overflow: hidden;
    position: relative;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    margin: 0 auto;
}

.video-wrapper-mobile video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: contain; /* 完整显示视频，不裁剪，保持原始比例 */
    background: #000;
    border-radius: 20px;
}

/* 如果浏览器不支持aspect-ratio，使用padding-top作为后备 */
@supports not (aspect-ratio: 9 / 16) {
    .video-wrapper-mobile {
        padding-top: 177.78%; /* 9:16 手机屏幕比例 (16/9 = 1.7778) */
    }
}

/* 全屏时的样式修复 */
.video-wrapper-mobile video:-webkit-full-screen {
    object-fit: contain !important;
    width: 100vw !important;
    height: 100vh !important;
    max-width: 100vw !important;
    max-height: 100vh !important;
    border-radius: 0 !important;
    position: fixed !important;
    top: 0 !important;
    left: 0 !important;
    background: #000 !important;
}

.video-wrapper-mobile video:-moz-full-screen {
    object-fit: contain !important;
    width: 100vw !important;
    height: 100vh !important;
    max-width: 100vw !important;
    max-height: 100vh !important;
    border-radius: 0 !important;
    position: fixed !important;
    top: 0 !important;
    left: 0 !important;
    background: #000 !important;
}

.video-wrapper-mobile video:-ms-fullscreen {
    object-fit: contain !important;
    width: 100vw !important;
    height: 100vh !important;
    max-width: 100vw !important;
    max-height: 100vh !important;
    border-radius: 0 !important;
    position: fixed !important;
    top: 0 !important;
    left: 0 !important;
    background: #000 !important;
}

.video-wrapper-mobile video:fullscreen {
    object-fit: contain !important;
    width: 100vw !important;
    height: 100vh !important;
    max-width: 100vw !important;
    max-height: 100vh !important;
    border-radius: 0 !important;
    position: fixed !important;
    top: 0 !important;
    left: 0 !important;
    background: #000 !important;
}

/* 视频优化加载样式 */
video[preload="metadata"] {
    cursor: pointer;
}

video[controls] {
    /* 确保控制栏可见 */
    -webkit-appearance: none;
}

.video-info {
    padding: 1.5rem;
}

.video-info h4 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.video-info p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* 联系我们 */
.contact {
    padding: 100px 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    position: relative;
    overflow: hidden;
}

.contact::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><defs><pattern id="grid" width="100" height="100" patternUnits="userSpaceOnUse"><path d="M 100 0 L 0 0 0 100" fill="none" stroke="rgba(255,255,255,0.05)" stroke-width="1"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

.contact .section-title {
    color: white;
    position: relative;
    z-index: 1;
}

.contact-content {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    z-index: 1;
}

.contact-card {
    background: white;
    border-radius: 24px;
    padding: 3.5rem 3rem;
    max-width: 500px;
    width: 100%;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.contact-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 25px 70px rgba(0, 0, 0, 0.35);
}

.contact-icon-wrapper {
    width: 80px;
    height: 80px;
    margin: 0 auto 1.5rem;
    background: linear-gradient(135deg, #0088cc 0%, #229ed9 100%);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 10px 30px rgba(0, 136, 204, 0.3);
}

.telegram-icon {
    width: 45px;
    height: 45px;
    color: white;
}

.contact-card-title {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
}

.contact-card-description {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: 2rem;
    line-height: 1.6;
}

.telegram-username {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #f5f7fa 0%, #e8ecf1 100%);
    padding: 1rem 2rem;
    border-radius: 12px;
    margin-bottom: 2rem;
    border: 2px solid var(--border-color);
    transition: all 0.3s ease;
}

.telegram-username:hover {
    border-color: #0088cc;
    background: linear-gradient(135deg, #ffffff 0%, #f5f7fa 100%);
    transform: scale(1.02);
}

.telegram-at {
    font-size: 1.5rem;
    font-weight: 600;
    color: #0088cc;
    margin-right: 0.25rem;
}

.telegram-name {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.5px;
}

.telegram-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    background: linear-gradient(135deg, #0088cc 0%, #229ed9 100%);
    color: white;
    padding: 1rem 2.5rem;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 136, 204, 0.4);
    margin-bottom: 1.5rem;
}

.telegram-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 136, 204, 0.5);
    background: linear-gradient(135deg, #0077b3 0%, #1e8cc7 100%);
}

.telegram-button:active {
    transform: translateY(0);
}

.telegram-button-icon {
    width: 24px;
    height: 24px;
    color: white;
}

.contact-service-time {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.95rem;
    padding: 0.75rem 1.5rem;
    background: var(--bg-light);
    border-radius: 8px;
}

.service-time-icon {
    width: 18px;
    height: 18px;
    color: #10b981;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.contact-item h4 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.contact-item p {
    color: var(--text-secondary);
}

.contact-form {
    background: var(--bg-light);
    padding: 2rem;
    border-radius: 12px;
}

.contact-form h3 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-family: inherit;
    font-size: 1rem;
    transition: border-color 0.3s;
}

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

.form-group textarea {
    resize: vertical;
}

/* 页脚 */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 3rem 0 1rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

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

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

.footer-section a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: color 0.3s;
}

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

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.7);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background: var(--bg-white);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow-md);
        padding: 2rem 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-toggle {
        display: flex;
    }

    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .demo-content {
        grid-template-columns: 1fr;
    }

    .contact {
        padding: 60px 0;
    }

    .contact-card {
        padding: 2.5rem 2rem;
        margin: 0 1rem;
    }

    .contact-icon-wrapper {
        width: 70px;
        height: 70px;
    }

    .telegram-icon {
        width: 40px;
        height: 40px;
    }

    .contact-card-title {
        font-size: 1.5rem;
    }

    .telegram-username {
        padding: 0.875rem 1.5rem;
    }

    .telegram-at,
    .telegram-name {
        font-size: 1.25rem;
    }

    .telegram-button {
        padding: 0.875rem 2rem;
        font-size: 1rem;
    }

    .contact-content {
        grid-template-columns: 1fr;
    }

    .api-item {
        flex-direction: column;
        align-items: flex-start;
    }

    .api-item code {
        width: 100%;
    }

    .advantages-grid {
        grid-template-columns: 1fr;
    }

    .videos-grid {
        grid-template-columns: 1fr;
    }
    
    .videos-grid-mobile {
        grid-template-columns: 1fr;
        max-width: 100%;
    }
    
    .video-item-mobile {
        max-width: 100%;
    }
    
    .video-wrapper-mobile {
        max-width: 280px;
        margin: 0 auto;
    }

    .video-section-title {
        font-size: 1.5rem;
    }
}

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