/* 海角传媒 - 主样式文件 | c1yzl4.cn */
/* ===== CSS变量 ===== */
:root {
  --primary: #0d3b6e;
  --primary-light: #1a5fa8;
  --accent: #e84c3d;
  --accent-light: #ff6b5b;
  --gold: #f0a500;
  --dark: #0a0f1e;
  --dark2: #111827;
  --dark3: #1f2937;
  --gray: #6b7280;
  --gray-light: #9ca3af;
  --light: #f3f4f6;
  --white: #ffffff;
  --border: #e5e7eb;
  --shadow: 0 4px 20px rgba(0,0,0,0.12);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.18);
  --radius: 12px;
  --radius-sm: 6px;
  --transition: all 0.3s ease;
  --font-main: 'PingFang SC','Microsoft YaHei','Hiragino Sans GB',sans-serif;
}

/* ===== 全局重置 ===== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;font-size:16px}
body{font-family:var(--font-main);background:#fff;color:#222;line-height:1.7;overflow-x:hidden}
a{color:inherit;text-decoration:none;transition:var(--transition)}
img{max-width:100%;height:auto;display:block}
ul,ol{list-style:none}
button{cursor:pointer;border:none;background:none;font-family:inherit}
input,textarea,select{font-family:inherit}

/* ===== 顶部公告栏 ===== */
.top-bar{background:var(--primary);color:rgba(255,255,255,0.85);font-size:13px;padding:6px 0;text-align:center}
.top-bar a{color:var(--gold);margin:0 8px}
.top-bar a:hover{text-decoration:underline}

/* ===== 头部导航 ===== */
.site-header{background:#fff;box-shadow:0 2px 12px rgba(0,0,0,0.08);position:sticky;top:0;z-index:1000;transition:var(--transition)}
.site-header.scrolled{box-shadow:0 4px 20px rgba(0,0,0,0.15)}
.header-inner{max-width:1280px;margin:0 auto;padding:0 20px;display:flex;align-items:center;height:70px;gap:24px}
.site-logo{display:flex;align-items:center;gap:10px;flex-shrink:0}
.site-logo img{height:44px;width:auto}
.site-logo .logo-text{font-size:22px;font-weight:700;color:var(--primary);letter-spacing:1px}
.site-logo .logo-sub{font-size:11px;color:var(--gray);display:block;line-height:1}

/* 主导航 */
.main-nav{flex:1}
.main-nav ul{display:flex;gap:4px;align-items:center}
.main-nav li{position:relative}
.main-nav a{display:block;padding:8px 14px;font-size:15px;color:#333;border-radius:var(--radius-sm);transition:var(--transition);white-space:nowrap}
.main-nav a:hover,.main-nav a.active{color:var(--primary);background:rgba(13,59,110,0.06)}
.main-nav .dropdown{position:absolute;top:calc(100% + 8px);left:0;background:#fff;border-radius:var(--radius);box-shadow:var(--shadow-lg);min-width:160px;opacity:0;visibility:hidden;transform:translateY(-8px);transition:var(--transition);z-index:100;border:1px solid var(--border)}
.main-nav li:hover .dropdown{opacity:1;visibility:visible;transform:translateY(0)}
.main-nav .dropdown a{padding:10px 16px;font-size:14px;border-radius:0;border-bottom:1px solid var(--border)}
.main-nav .dropdown a:last-child{border-bottom:none}
.main-nav .dropdown a:hover{background:var(--light);color:var(--primary)}

/* 头部右侧 */
.header-actions{display:flex;align-items:center;gap:12px;flex-shrink:0}
.btn-login{padding:8px 20px;border-radius:20px;border:1.5px solid var(--primary);color:var(--primary);font-size:14px;transition:var(--transition)}
.btn-login:hover{background:var(--primary);color:#fff}
.btn-join{padding:8px 20px;border-radius:20px;background:var(--accent);color:#fff;font-size:14px;transition:var(--transition)}
.btn-join:hover{background:var(--accent-light);transform:translateY(-1px)}

/* ===== 搜索框 ===== */
.search-bar-wrap{background:linear-gradient(135deg,var(--primary) 0%,var(--primary-light) 100%);padding:16px 0}
.search-bar-inner{max-width:1280px;margin:0 auto;padding:0 20px;display:flex;align-items:center;gap:12px}
.search-form{display:flex;flex:1;max-width:700px;margin:0 auto;background:#fff;border-radius:30px;overflow:hidden;box-shadow:0 2px 12px rgba(0,0,0,0.15)}
.search-form input{flex:1;border:none;outline:none;padding:12px 20px;font-size:15px;color:#333;background:transparent}
.search-form input::placeholder{color:#aaa}
.search-form button{padding:10px 28px;background:var(--accent);color:#fff;font-size:15px;border-radius:0 30px 30px 0;transition:var(--transition);white-space:nowrap}
.search-form button:hover{background:var(--accent-light)}
.search-tags{display:flex;gap:8px;flex-wrap:wrap;justify-content:center;margin-top:8px}
.search-tags a{color:rgba(255,255,255,0.8);font-size:13px;padding:3px 10px;border:1px solid rgba(255,255,255,0.3);border-radius:12px;transition:var(--transition)}
.search-tags a:hover{background:rgba(255,255,255,0.15);color:#fff}

/* ===== 轮播Banner ===== */
.hero-banner{position:relative;overflow:hidden;background:var(--dark)}
.hero-slide{position:relative;height:520px;overflow:hidden}
.hero-slide img{width:100%;height:100%;object-fit:cover;opacity:0.7}
.hero-overlay{position:absolute;inset:0;background:linear-gradient(135deg,rgba(13,59,110,0.85) 0%,rgba(10,15,30,0.5) 100%)}
.hero-content{position:absolute;inset:0;display:flex;flex-direction:column;justify-content:center;padding:0 80px;max-width:700px}
.hero-badge{display:inline-block;background:var(--accent);color:#fff;font-size:12px;padding:4px 12px;border-radius:12px;margin-bottom:16px;letter-spacing:1px}
.hero-title{font-size:46px;font-weight:800;color:#fff;line-height:1.2;margin-bottom:16px;text-shadow:0 2px 8px rgba(0,0,0,0.3)}
.hero-title span{color:var(--gold)}
.hero-desc{font-size:16px;color:rgba(255,255,255,0.85);margin-bottom:28px;line-height:1.8}
.hero-btns{display:flex;gap:14px;flex-wrap:wrap}
.btn-primary{padding:13px 32px;background:var(--accent);color:#fff;border-radius:30px;font-size:16px;font-weight:600;transition:var(--transition);display:inline-flex;align-items:center;gap:8px}
.btn-primary:hover{background:var(--accent-light);transform:translateY(-2px);box-shadow:0 6px 20px rgba(232,76,61,0.4)}
.btn-outline{padding:13px 32px;border:2px solid rgba(255,255,255,0.7);color:#fff;border-radius:30px;font-size:16px;font-weight:600;transition:var(--transition)}
.btn-outline:hover{background:rgba(255,255,255,0.15);border-color:#fff}

/* 轮播控制 */
.banner-dots{position:absolute;bottom:20px;left:50%;transform:translateX(-50%);display:flex;gap:8px;z-index:10}
.banner-dots span{width:8px;height:8px;border-radius:50%;background:rgba(255,255,255,0.5);cursor:pointer;transition:var(--transition)}
.banner-dots span.active{background:#fff;width:24px;border-radius:4px}

/* ===== 统计数据栏 ===== */
.stats-bar{background:var(--primary);padding:28px 0}
.stats-inner{max-width:1280px;margin:0 auto;padding:0 20px;display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.stat-item{text-align:center;color:#fff}
.stat-num{font-size:36px;font-weight:800;color:var(--gold);line-height:1}
.stat-unit{font-size:16px;color:var(--gold)}
.stat-label{font-size:13px;color:rgba(255,255,255,0.75);margin-top:6px}

/* ===== 通用容器 ===== */
.container{max-width:1280px;margin:0 auto;padding:0 20px}
.section{padding:70px 0}
.section-alt{background:var(--light)}
.section-header{text-align:center;margin-bottom:48px}
.section-tag{display:inline-block;background:rgba(13,59,110,0.08);color:var(--primary);font-size:12px;padding:4px 14px;border-radius:12px;margin-bottom:12px;letter-spacing:1px;font-weight:600}
.section-title{font-size:32px;font-weight:800;color:var(--dark);margin-bottom:12px}
.section-title span{color:var(--accent)}
.section-desc{font-size:15px;color:var(--gray);max-width:600px;margin:0 auto}
.section-more{display:inline-flex;align-items:center;gap:6px;color:var(--primary);font-size:14px;font-weight:600;margin-top:8px;transition:var(--transition)}
.section-more:hover{color:var(--accent);gap:10px}

/* ===== 视频卡片 ===== */
.video-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.video-card{background:#fff;border-radius:var(--radius);overflow:hidden;box-shadow:0 2px 12px rgba(0,0,0,0.08);transition:var(--transition);cursor:pointer}
.video-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg)}
.video-thumb{position:relative;aspect-ratio:16/9;overflow:hidden;background:var(--dark3)}
.video-thumb img{width:100%;height:100%;object-fit:cover;transition:transform 0.4s ease}
.video-card:hover .video-thumb img{transform:scale(1.05)}
.video-play-btn{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;background:rgba(0,0,0,0);transition:var(--transition)}
.video-card:hover .video-play-btn{background:rgba(0,0,0,0.4)}
.play-icon{width:52px;height:52px;background:rgba(255,255,255,0.95);border-radius:50%;display:flex;align-items:center;justify-content:center;opacity:0;transform:scale(0.8);transition:var(--transition)}
.video-card:hover .play-icon{opacity:1;transform:scale(1)}
.play-icon svg{fill:var(--accent);margin-left:4px}
.video-duration{position:absolute;bottom:8px;right:8px;background:rgba(0,0,0,0.75);color:#fff;font-size:12px;padding:2px 7px;border-radius:4px}
.video-tag{position:absolute;top:8px;left:8px;background:var(--accent);color:#fff;font-size:11px;padding:2px 8px;border-radius:4px}
.video-info{padding:14px}
.video-title{font-size:14px;font-weight:600;color:#222;line-height:1.5;margin-bottom:8px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.video-meta{display:flex;align-items:center;gap:12px;font-size:12px;color:var(--gray)}
.video-meta span{display:flex;align-items:center;gap:3px}
.video-author{display:flex;align-items:center;gap:6px;margin-top:8px}
.author-avatar{width:22px;height:22px;border-radius:50%;background:var(--primary);display:flex;align-items:center;justify-content:center;color:#fff;font-size:10px;flex-shrink:0}
.author-name{font-size:12px;color:var(--gray)}

/* ===== 热门视频大卡片 ===== */
.video-featured{display:grid;grid-template-columns:1fr 1fr;gap:24px;align-items:start}
.video-main-card{background:#fff;border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow)}
.video-main-card .video-thumb{aspect-ratio:16/9}
.video-main-card .video-info{padding:20px}
.video-main-card .video-title{font-size:18px;margin-bottom:12px}
.video-main-card .video-desc{font-size:14px;color:var(--gray);line-height:1.7;margin-bottom:12px}
.video-side-list{display:flex;flex-direction:column;gap:14px}
.video-side-item{display:flex;gap:12px;background:#fff;border-radius:var(--radius-sm);overflow:hidden;box-shadow:0 2px 8px rgba(0,0,0,0.06);cursor:pointer;transition:var(--transition)}
.video-side-item:hover{transform:translateX(4px);box-shadow:0 4px 16px rgba(0,0,0,0.1)}
.video-side-item .video-thumb{width:120px;flex-shrink:0;aspect-ratio:16/9}
.video-side-item .video-info{padding:10px 12px 10px 0;flex:1}
.video-side-item .video-title{font-size:13px;-webkit-line-clamp:2}

/* ===== 分类标签栏 ===== */
.category-tabs{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:28px}
.cat-tab{padding:7px 18px;border-radius:20px;font-size:14px;color:var(--gray);background:var(--light);transition:var(--transition);cursor:pointer;border:1.5px solid transparent}
.cat-tab:hover,.cat-tab.active{background:var(--primary);color:#fff;border-color:var(--primary)}

/* ===== 专家展示 ===== */
.expert-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
.expert-card{background:#fff;border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);transition:var(--transition);text-align:center}
.expert-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg)}
.expert-avatar{width:100%;aspect-ratio:1;overflow:hidden;position:relative}
.expert-avatar img{width:100%;height:100%;object-fit:cover;transition:transform 0.4s}
.expert-card:hover .expert-avatar img{transform:scale(1.05)}
.expert-body{padding:18px}
.expert-name{font-size:16px;font-weight:700;color:var(--dark);margin-bottom:4px}
.expert-role{font-size:13px;color:var(--accent);margin-bottom:8px;font-weight:600}
.expert-desc{font-size:13px;color:var(--gray);line-height:1.6;margin-bottom:12px}
.expert-awards{display:flex;flex-wrap:wrap;gap:4px;justify-content:center;margin-bottom:12px}
.award-tag{font-size:11px;background:rgba(13,59,110,0.08);color:var(--primary);padding:3px 8px;border-radius:10px}
.expert-btns{display:flex;gap:8px;justify-content:center}
.btn-sm{padding:6px 14px;border-radius:16px;font-size:12px;transition:var(--transition)}
.btn-sm-primary{background:var(--primary);color:#fff}
.btn-sm-primary:hover{background:var(--primary-light)}
.btn-sm-outline{border:1.5px solid var(--primary);color:var(--primary)}
.btn-sm-outline:hover{background:var(--primary);color:#fff}

/* ===== 合作品牌 ===== */
.partners-grid{display:grid;grid-template-columns:repeat(6,1fr);gap:16px;align-items:center}
.partner-item{background:#fff;border-radius:var(--radius-sm);padding:18px;display:flex;align-items:center;justify-content:center;box-shadow:0 2px 8px rgba(0,0,0,0.06);transition:var(--transition);min-height:70px}
.partner-item:hover{box-shadow:var(--shadow);transform:translateY(-2px)}
.partner-name{font-size:14px;font-weight:700;color:var(--primary);text-align:center}

/* ===== 如何加入 ===== */
.howto-steps{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
.step-card{text-align:center;padding:32px 20px;background:#fff;border-radius:var(--radius);box-shadow:var(--shadow);position:relative;transition:var(--transition)}
.step-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg)}
.step-num{width:52px;height:52px;border-radius:50%;background:linear-gradient(135deg,var(--primary),var(--primary-light));color:#fff;font-size:22px;font-weight:800;display:flex;align-items:center;justify-content:center;margin:0 auto 16px}
.step-title{font-size:16px;font-weight:700;color:var(--dark);margin-bottom:8px}
.step-desc{font-size:13px;color:var(--gray);line-height:1.7}
.step-arrow{position:absolute;right:-12px;top:50%;transform:translateY(-50%);color:var(--primary-light);font-size:20px;z-index:1}

/* ===== FAQ ===== */
.faq-list{max-width:860px;margin:0 auto}
.faq-item{background:#fff;border-radius:var(--radius);margin-bottom:12px;box-shadow:0 2px 8px rgba(0,0,0,0.06);overflow:hidden;border:1px solid var(--border)}
.faq-question{padding:18px 24px;display:flex;align-items:center;justify-content:space-between;cursor:pointer;font-size:15px;font-weight:600;color:var(--dark);transition:var(--transition)}
.faq-question:hover{color:var(--primary)}
.faq-question .faq-icon{width:24px;height:24px;border-radius:50%;background:var(--light);display:flex;align-items:center;justify-content:center;flex-shrink:0;transition:var(--transition);font-size:16px;color:var(--primary)}
.faq-item.open .faq-icon{background:var(--primary);color:#fff;transform:rotate(45deg)}
.faq-answer{max-height:0;overflow:hidden;transition:max-height 0.4s ease,padding 0.3s}
.faq-item.open .faq-answer{max-height:300px}
.faq-answer-inner{padding:0 24px 18px;font-size:14px;color:var(--gray);line-height:1.8}

/* ===== 用户评价 ===== */
.review-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.review-card{background:#fff;border-radius:var(--radius);padding:22px;box-shadow:var(--shadow);transition:var(--transition)}
.review-card:hover{transform:translateY(-3px);box-shadow:var(--shadow-lg)}
.review-stars{color:var(--gold);font-size:16px;margin-bottom:10px;letter-spacing:2px}
.review-text{font-size:14px;color:#444;line-height:1.8;margin-bottom:14px;font-style:italic}
.review-user{display:flex;align-items:center;gap:10px}
.review-avatar{width:38px;height:38px;border-radius:50%;background:linear-gradient(135deg,var(--primary),var(--accent));display:flex;align-items:center;justify-content:center;color:#fff;font-size:14px;font-weight:700;flex-shrink:0}
.review-name{font-size:14px;font-weight:600;color:var(--dark)}
.review-date{font-size:12px;color:var(--gray-light)}

/* ===== 联系我们 ===== */
.contact-grid{display:grid;grid-template-columns:1fr 1fr;gap:48px;align-items:start}
.contact-info h3{font-size:22px;font-weight:700;color:var(--dark);margin-bottom:20px}
.contact-item{display:flex;gap:14px;margin-bottom:18px;align-items:flex-start}
.contact-icon{width:44px;height:44px;border-radius:10px;background:rgba(13,59,110,0.08);display:flex;align-items:center;justify-content:center;flex-shrink:0;font-size:20px}
.contact-label{font-size:13px;color:var(--gray);margin-bottom:3px}
.contact-value{font-size:15px;color:var(--dark);font-weight:600}
.qr-group{display:flex;gap:24px;margin-top:24px}
.qr-item{text-align:center}
.qr-item img{width:120px;height:120px;border-radius:var(--radius-sm);border:2px solid var(--border)}
.qr-item p{font-size:12px;color:var(--gray);margin-top:6px}
.community-links{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;margin-top:20px}
.community-link{display:flex;align-items:center;gap:10px;padding:12px 16px;background:var(--light);border-radius:var(--radius-sm);transition:var(--transition);font-size:14px;color:var(--dark)}
.community-link:hover{background:var(--primary);color:#fff}
.community-link .cl-icon{font-size:20px}

/* ===== 社交分享 ===== */
.share-bar{background:var(--light);padding:20px 0}
.share-inner{max-width:1280px;margin:0 auto;padding:0 20px;display:flex;align-items:center;gap:16px;flex-wrap:wrap}
.share-label{font-size:14px;color:var(--gray);font-weight:600}
.share-btns{display:flex;gap:10px;flex-wrap:wrap}
.share-btn{padding:8px 18px;border-radius:20px;font-size:13px;font-weight:600;transition:var(--transition);display:flex;align-items:center;gap:6px}
.share-wechat{background:#07c160;color:#fff}
.share-weibo{background:#e6162d;color:#fff}
.share-douyin{background:#000;color:#fff}
.share-bilibili{background:#00a1d6;color:#fff}
.share-btn:hover{opacity:0.85;transform:translateY(-1px)}

/* ===== 页脚 ===== */
.site-footer{background:var(--dark);color:rgba(255,255,255,0.75);padding:60px 0 0}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:40px;margin-bottom:48px}
.footer-brand .brand-logo{display:flex;align-items:center;gap:10px;margin-bottom:16px}
.footer-brand .brand-logo img{height:40px;filter:brightness(0) invert(1)}
.footer-brand .brand-name{font-size:20px;font-weight:700;color:#fff}
.footer-brand p{font-size:14px;line-height:1.8;margin-bottom:16px}
.footer-social{display:flex;gap:10px}
.social-icon{width:36px;height:36px;border-radius:50%;background:rgba(255,255,255,0.1);display:flex;align-items:center;justify-content:center;font-size:15px;transition:var(--transition);color:#fff}
.social-icon:hover{background:var(--accent);transform:translateY(-2px)}
.footer-col h4{font-size:16px;font-weight:700;color:#fff;margin-bottom:18px;padding-bottom:10px;border-bottom:1px solid rgba(255,255,255,0.1)}
.footer-col ul li{margin-bottom:10px}
.footer-col ul li a{font-size:14px;color:rgba(255,255,255,0.65);transition:var(--transition)}
.footer-col ul li a:hover{color:#fff;padding-left:4px}
.footer-bottom{border-top:1px solid rgba(255,255,255,0.1);padding:20px 0;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:12px}
.footer-bottom p{font-size:13px;color:rgba(255,255,255,0.5)}
.footer-bottom a{color:rgba(255,255,255,0.6);margin:0 6px;font-size:13px}
.footer-bottom a:hover{color:#fff}
.footer-logo-bottom{display:flex;align-items:center;gap:8px}
.footer-logo-bottom img{height:30px;filter:brightness(0) invert(1)}

/* ===== 面包屑 ===== */
.breadcrumb{background:var(--light);padding:12px 0;border-bottom:1px solid var(--border)}
.breadcrumb-inner{max-width:1280px;margin:0 auto;padding:0 20px;display:flex;align-items:center;gap:8px;font-size:13px;color:var(--gray)}
.breadcrumb a{color:var(--primary)}
.breadcrumb a:hover{text-decoration:underline}
.breadcrumb-sep{color:var(--gray-light)}

/* ===== 内页头部 ===== */
.page-hero{background:linear-gradient(135deg,var(--primary) 0%,var(--dark) 100%);padding:60px 0;text-align:center;color:#fff}
.page-hero h1{font-size:38px;font-weight:800;margin-bottom:12px}
.page-hero p{font-size:16px;color:rgba(255,255,255,0.8);max-width:600px;margin:0 auto}

/* ===== AI赋能区块 ===== */
.ai-features{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.ai-card{background:#fff;border-radius:var(--radius);padding:28px;box-shadow:var(--shadow);border-left:4px solid var(--primary);transition:var(--transition)}
.ai-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg);border-left-color:var(--accent)}
.ai-icon{font-size:36px;margin-bottom:14px}
.ai-title{font-size:17px;font-weight:700;color:var(--dark);margin-bottom:8px}
.ai-desc{font-size:14px;color:var(--gray);line-height:1.7}

/* ===== 内容文章 ===== */
.article-content{font-size:15px;line-height:1.9;color:#333}
.article-content h2{font-size:22px;font-weight:700;color:var(--dark);margin:28px 0 14px;padding-left:12px;border-left:4px solid var(--primary)}
.article-content h3{font-size:18px;font-weight:700;color:var(--dark);margin:22px 0 10px}
.article-content p{margin-bottom:16px}
.article-content ul{padding-left:20px;margin-bottom:16px}
.article-content ul li{list-style:disc;margin-bottom:8px}

/* ===== 移动端汉堡菜单 ===== */
.menu-toggle{display:none;flex-direction:column;gap:5px;cursor:pointer;padding:4px}
.menu-toggle span{display:block;width:24px;height:2px;background:var(--dark);border-radius:2px;transition:var(--transition)}

/* ===== 回到顶部 ===== */
.back-top{position:fixed;bottom:30px;right:30px;width:44px;height:44px;background:var(--primary);color:#fff;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:18px;box-shadow:var(--shadow);opacity:0;visibility:hidden;transition:var(--transition);z-index:999;cursor:pointer}
.back-top.show{opacity:1;visibility:visible}
.back-top:hover{background:var(--accent);transform:translateY(-3px)}

/* ===== 悬浮客服 ===== */
.float-service{position:fixed;right:30px;bottom:90px;display:flex;flex-direction:column;gap:10px;z-index:998}
.float-btn{width:44px;height:44px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:18px;box-shadow:var(--shadow);transition:var(--transition);cursor:pointer;color:#fff}
.float-btn:hover{transform:scale(1.1)}
.float-qq{background:#12b7f5}
.float-wechat{background:#07c160}
.float-service-label{position:absolute;right:54px;top:50%;transform:translateY(-50%);background:rgba(0,0,0,0.75);color:#fff;font-size:12px;padding:4px 10px;border-radius:4px;white-space:nowrap;opacity:0;transition:var(--transition);pointer-events:none}
.float-btn:hover .float-service-label{opacity:1}

/* ===== 响应式 ===== */
@media(max-width:1100px){
  .video-grid{grid-template-columns:repeat(3,1fr)}
  .expert-grid{grid-template-columns:repeat(3,1fr)}
  .partners-grid{grid-template-columns:repeat(4,1fr)}
  .footer-grid{grid-template-columns:1fr 1fr}
}
@media(max-width:900px){
  .hero-slide{height:380px}
  .hero-content{padding:0 40px}
  .hero-title{font-size:32px}
  .stats-inner{grid-template-columns:repeat(2,1fr)}
  .video-grid{grid-template-columns:repeat(2,1fr)}
  .expert-grid{grid-template-columns:repeat(2,1fr)}
  .howto-steps{grid-template-columns:repeat(2,1fr)}
  .review-grid{grid-template-columns:repeat(2,1fr)}
  .contact-grid{grid-template-columns:1fr}
  .ai-features{grid-template-columns:1fr 1fr}
  .video-featured{grid-template-columns:1fr}
}
@media(max-width:640px){
  .header-inner{height:60px}
  .site-logo .logo-text{font-size:18px}
  .main-nav{display:none}
  .main-nav.open{display:block;position:fixed;inset:60px 0 0;background:#fff;padding:20px;overflow-y:auto;z-index:999}
  .main-nav.open ul{flex-direction:column}
  .main-nav.open a{padding:12px 16px;border-bottom:1px solid var(--border)}
  .menu-toggle{display:flex}
  .hero-slide{height:280px}
  .hero-content{padding:0 20px}
  .hero-title{font-size:22px}
  .hero-desc{font-size:13px;display:none}
  .stats-inner{grid-template-columns:repeat(2,1fr)}
  .stat-num{font-size:26px}
  .section{padding:48px 0}
  .section-title{font-size:24px}
  .video-grid{grid-template-columns:repeat(2,1fr)}
  .expert-grid{grid-template-columns:1fr 1fr}
  .howto-steps{grid-template-columns:1fr}
  .review-grid{grid-template-columns:1fr}
  .partners-grid{grid-template-columns:repeat(3,1fr)}
  .footer-grid{grid-template-columns:1fr}
  .ai-features{grid-template-columns:1fr}
  .video-featured{grid-template-columns:1fr}
  .search-form{max-width:100%}
  .back-top,.float-service{right:16px}
}

/* 动画类 */
.animated{animation:fadeInUp 0.5s ease both}
@keyframes fadeInUp{from{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}