/* ============================================
   四虎视频 - 汽车改装视频社区 CSS
   品牌色: #C41E3A (赛车红) #1A1A2E (深夜蓝) #16213E (暗蓝) #0F3460 (海军蓝) #E94560 (亮红)
   ============================================ */

/* === 基础重置 === */
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;font-size:16px}
body{font-family:"PingFang SC","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;color:#e0e0e0;background:#0d0d1a;line-height:1.8;overflow-x:hidden}
a{color:#E94560;text-decoration:none;transition:color .3s}
a:hover{color:#ff6b81}
img{max-width:100%;height:auto;display:block}
ul,ol{list-style:none}
h1,h2,h3,h4,h5,h6{font-weight:700;line-height:1.3;color:#fff}

/* === 容器 === */
.container{max-width:1200px;margin:0 auto;padding:0 20px}
.section-wrap{padding:60px 0}
.section-wrap:nth-child(even){background:#111128}

/* === 头部导航 === */
.site-header{background:rgba(13,13,26,.95);backdrop-filter:blur(10px);position:fixed;top:0;left:0;width:100%;z-index:1000;border-bottom:1px solid rgba(233,69,96,.2);transition:all .3s}
.site-header.scrolled{background:rgba(13,13,26,.98);box-shadow:0 2px 20px rgba(233,69,96,.15)}
.header-inner{display:flex;align-items:center;justify-content:space-between;padding:10px 20px;max-width:1200px;margin:0 auto}
.logo-wrap{display:flex;align-items:center;gap:10px}
.logo-wrap img{width:42px;height:42px;border-radius:8px}
.logo-wrap .brand-name{font-size:22px;font-weight:800;color:#fff;letter-spacing:1px}
.logo-wrap .brand-name span{color:#E94560}

/* 导航菜单 */
.main-nav{display:flex;align-items:center;gap:0}
.main-nav a{padding:10px 16px;font-size:14px;color:#ccc;transition:all .3s;position:relative;white-space:nowrap}
.main-nav a:hover,.main-nav a.active{color:#E94560}
.main-nav a::after{content:'';position:absolute;bottom:0;left:50%;width:0;height:2px;background:#E94560;transition:all .3s;transform:translateX(-50%)}
.main-nav a:hover::after,.main-nav a.active::after{width:60%}

/* 移动菜单按钮 */
.menu-toggle{display:none;flex-direction:column;gap:5px;cursor:pointer;padding:5px}
.menu-toggle span{width:25px;height:2px;background:#fff;transition:all .3s}

/* === 搜索栏 === */
.search-bar{background:#111128;padding:12px 0;border-bottom:1px solid rgba(233,69,96,.1)}
.search-bar .container{display:flex;justify-content:center}
.search-box{display:flex;max-width:600px;width:100%}
.search-box input{flex:1;padding:10px 20px;background:#1a1a3e;border:1px solid rgba(233,69,96,.3);border-right:none;border-radius:25px 0 0 25px;color:#fff;font-size:14px;outline:none;transition:border-color .3s}
.search-box input:focus{border-color:#E94560}
.search-box input::placeholder{color:#666}
.search-box button{padding:10px 25px;background:linear-gradient(135deg,#C41E3A,#E94560);border:none;border-radius:0 25px 25px 0;color:#fff;font-size:14px;cursor:pointer;transition:opacity .3s;white-space:nowrap}
.search-box button:hover{opacity:.85}

/* === Hero Banner === */
.hero-section{position:relative;height:80vh;min-height:500px;overflow:hidden;margin-top:62px}
.hero-bg{position:absolute;inset:0;background-size:cover;background-position:center;filter:brightness(.6)}
.hero-overlay{position:absolute;inset:0;background:linear-gradient(180deg,rgba(13,13,26,.3) 0%,rgba(13,13,26,.8) 100%)}
.hero-content{position:relative;z-index:2;height:100%;display:flex;flex-direction:column;justify-content:center;align-items:center;text-align:center;padding:0 20px}
.hero-content h1{font-size:48px;margin-bottom:16px;text-shadow:0 2px 20px rgba(0,0,0,.5)}
.hero-content h1 span{color:#E94560}
.hero-content p{font-size:20px;color:#ccc;max-width:700px;margin-bottom:30px}
.hero-tags{display:flex;flex-wrap:wrap;gap:10px;justify-content:center;margin-bottom:30px}
.hero-tags span{padding:6px 16px;background:rgba(233,69,96,.15);border:1px solid rgba(233,69,96,.3);border-radius:20px;font-size:13px;color:#E94560}
.hero-btn{display:inline-block;padding:14px 40px;background:linear-gradient(135deg,#C41E3A,#E94560);color:#fff;font-size:16px;font-weight:600;border-radius:30px;transition:all .3s;box-shadow:0 4px 20px rgba(233,69,96,.4)}
.hero-btn:hover{transform:translateY(-2px);box-shadow:0 6px 30px rgba(233,69,96,.6);color:#fff}

/* === 面包屑 === */
.breadcrumb{padding:15px 0;font-size:13px;color:#888}
.breadcrumb a{color:#aaa}
.breadcrumb a:hover{color:#E94560}
.breadcrumb span{margin:0 8px;color:#555}

/* === 区块标题 === */
.section-title{text-align:center;margin-bottom:45px}
.section-title h2{font-size:32px;margin-bottom:10px;position:relative;display:inline-block}
.section-title h2::after{content:'';display:block;width:60px;height:3px;background:linear-gradient(90deg,#C41E3A,#E94560);margin:12px auto 0}
.section-title p{color:#999;font-size:15px;margin-top:10px}

/* === 视频卡片 === */
.video-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:24px}
.video-card{background:#1a1a3e;border-radius:12px;overflow:hidden;transition:all .3s;border:1px solid rgba(233,69,96,.1)}
.video-card:hover{transform:translateY(-5px);box-shadow:0 10px 30px rgba(233,69,96,.2);border-color:rgba(233,69,96,.3)}
.video-thumb{position:relative;padding-top:56.25%;overflow:hidden}
.video-thumb img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;transition:transform .5s}
.video-card:hover .video-thumb img{transform:scale(1.05)}
.play-btn{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);width:60px;height:60px;background:rgba(233,69,96,.85);border-radius:50%;display:flex;align-items:center;justify-content:center;opacity:0;transition:all .3s;cursor:pointer}
.play-btn::after{content:'';border-style:solid;border-width:10px 0 10px 18px;border-color:transparent transparent transparent #fff;margin-left:3px}
.video-card:hover .play-btn{opacity:1}
.video-duration{position:absolute;bottom:8px;right:8px;background:rgba(0,0,0,.8);color:#fff;padding:2px 8px;border-radius:4px;font-size:12px}
.video-info{padding:16px}
.video-info h3{font-size:15px;margin-bottom:8px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;line-height:1.5}
.video-meta{display:flex;align-items:center;gap:12px;font-size:12px;color:#888}
.video-meta .views::before{content:'';display:inline-block;width:14px;height:14px;background:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='%23888' viewBox='0 0 24 24'%3E%3Cpath d='M12 4.5C7 4.5 2.73 7.61 1 12c1.73 4.39 6 7.5 11 7.5s9.27-3.11 11-7.5c-1.73-4.39-6-7.5-11-7.5zM12 17c-2.76 0-5-2.24-5-5s2.24-5 5-5 5 2.24 5 5-2.24 5-5 5zm0-8c-1.66 0-3 1.34-3 3s1.34 3 3 3 3-1.34 3-3-1.34-3-3-3z'/%3E%3C/svg%3E") center/contain no-repeat;vertical-align:middle;margin-right:3px}
.video-meta .likes::before{content:'';display:inline-block;width:14px;height:14px;background:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='%23888' viewBox='0 0 24 24'%3E%3Cpath d='M1 21h4V9H1v12zm22-11c0-1.1-.9-2-2-2h-6.31l.95-4.57.03-.32c0-.41-.17-.79-.44-1.06L14.17 1 7.59 7.59C7.22 7.95 7 8.45 7 9v10c0 1.1.9 2 2 2h9c.83 0 1.54-.5 1.84-1.22l3.02-7.05c.09-.23.14-.47.14-.73v-2z'/%3E%3C/svg%3E") center/contain no-repeat;vertical-align:middle;margin-right:3px}
.video-tags{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}
.video-tags span{padding:2px 10px;background:rgba(233,69,96,.1);border-radius:12px;font-size:11px;color:#E94560}

/* === 功能模块网格 === */
.feature-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:24px}
.feature-card{background:#1a1a3e;border-radius:12px;padding:30px 24px;text-align:center;transition:all .3s;border:1px solid rgba(233,69,96,.08)}
.feature-card:hover{transform:translateY(-5px);border-color:rgba(233,69,96,.3);box-shadow:0 8px 25px rgba(233,69,96,.15)}
.feature-icon{width:64px;height:64px;margin:0 auto 18px;background:linear-gradient(135deg,rgba(196,30,58,.2),rgba(233,69,96,.2));border-radius:16px;display:flex;align-items:center;justify-content:center;font-size:28px}
.feature-card h3{font-size:18px;margin-bottom:10px}
.feature-card p{font-size:14px;color:#999;line-height:1.7}

/* === 专家团队 === */
.expert-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:24px}
.expert-card{background:#1a1a3e;border-radius:12px;overflow:hidden;transition:all .3s;border:1px solid rgba(233,69,96,.08)}
.expert-card:hover{transform:translateY(-5px);border-color:rgba(233,69,96,.3)}
.expert-photo{height:280px;overflow:hidden}
.expert-photo img{width:100%;height:100%;object-fit:cover;transition:transform .5s}
.expert-card:hover .expert-photo img{transform:scale(1.05)}
.expert-info{padding:20px}
.expert-info h3{font-size:18px;margin-bottom:4px}
.expert-info .role{color:#E94560;font-size:13px;margin-bottom:10px}
.expert-info p{font-size:13px;color:#999;line-height:1.6;margin-bottom:12px}
.expert-btns{display:flex;gap:10px}
.expert-btns a{flex:1;text-align:center;padding:8px 0;border-radius:6px;font-size:13px;transition:all .3s}
.expert-btns .btn-contact{background:rgba(233,69,96,.15);color:#E94560;border:1px solid rgba(233,69,96,.3)}
.expert-btns .btn-contact:hover{background:#E94560;color:#fff}
.expert-btns .btn-works{background:rgba(255,255,255,.05);color:#ccc;border:1px solid rgba(255,255,255,.1)}
.expert-btns .btn-works:hover{background:rgba(255,255,255,.1)}

/* === 合作品牌Logo墙 === */
.brand-wall{display:flex;flex-wrap:wrap;justify-content:center;gap:30px;align-items:center}
.brand-wall .brand-item{width:120px;height:60px;background:#1a1a3e;border-radius:8px;display:flex;align-items:center;justify-content:center;padding:10px;border:1px solid rgba(233,69,96,.08);transition:all .3s;font-size:14px;color:#888;font-weight:600}
.brand-wall .brand-item:hover{border-color:rgba(233,69,96,.3);transform:scale(1.05)}

/* === FAQ === */
.faq-list{max-width:800px;margin:0 auto}
.faq-item{background:#1a1a3e;border-radius:10px;margin-bottom:12px;border:1px solid rgba(233,69,96,.08);overflow:hidden}
.faq-question{padding:18px 24px;cursor:pointer;display:flex;justify-content:space-between;align-items:center;font-weight:600;font-size:15px;transition:all .3s;color:#ddd}
.faq-question:hover{color:#E94560}
.faq-question::after{content:'+';font-size:22px;color:#E94560;transition:transform .3s}
.faq-item.active .faq-question::after{transform:rotate(45deg)}
.faq-answer{max-height:0;overflow:hidden;transition:max-height .4s ease;padding:0 24px}
.faq-item.active .faq-answer{max-height:300px;padding:0 24px 18px}
.faq-answer p{font-size:14px;color:#999;line-height:1.8}

/* === 用户评价 === */
.review-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:20px}
.review-card{background:#1a1a3e;border-radius:12px;padding:24px;border:1px solid rgba(233,69,96,.08)}
.review-stars{color:#E94560;font-size:16px;margin-bottom:10px;letter-spacing:2px}
.review-text{font-size:14px;color:#bbb;line-height:1.8;margin-bottom:14px;font-style:italic}
.review-author{display:flex;align-items:center;gap:10px}
.review-avatar{width:40px;height:40px;border-radius:50%;background:linear-gradient(135deg,#C41E3A,#E94560);display:flex;align-items:center;justify-content:center;color:#fff;font-weight:700;font-size:16px}
.review-name{font-size:14px;font-weight:600;color:#ddd}
.review-date{font-size:12px;color:#777}

/* === 联系我们 === */
.contact-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:24px}
.contact-card{background:#1a1a3e;border-radius:12px;padding:24px;border:1px solid rgba(233,69,96,.08)}
.contact-card h3{font-size:18px;margin-bottom:15px;color:#E94560}
.contact-item{display:flex;align-items:flex-start;gap:10px;margin-bottom:12px;font-size:14px;color:#bbb}
.contact-item strong{color:#ddd;min-width:70px}

/* === How-To指南 === */
.howto-steps{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:20px;margin-top:30px}
.howto-step{background:#1a1a3e;border-radius:12px;padding:24px;text-align:center;position:relative;border:1px solid rgba(233,69,96,.08)}
.step-number{width:40px;height:40px;background:linear-gradient(135deg,#C41E3A,#E94560);border-radius:50%;display:flex;align-items:center;justify-content:center;margin:0 auto 15px;font-size:18px;font-weight:700;color:#fff}
.howto-step h4{font-size:16px;margin-bottom:8px}
.howto-step p{font-size:13px;color:#999}

/* === 社交分享 === */
.share-bar{display:flex;justify-content:center;gap:15px;padding:20px 0}
.share-btn{width:44px;height:44px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:18px;transition:all .3s;cursor:pointer;border:none;color:#fff}
.share-btn.wechat{background:#07C160}
.share-btn.weibo{background:#E6162D}
.share-btn.douyin{background:#161823}
.share-btn.bilibili{background:#00A1D6}
.share-btn:hover{transform:scale(1.15);opacity:.9}

/* === 页脚 === */
.site-footer{background:#0a0a18;border-top:1px solid rgba(233,69,96,.15);padding:50px 0 0}
.footer-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:30px;margin-bottom:40px}
.footer-col h4{font-size:16px;margin-bottom:15px;color:#E94560}
.footer-col p,.footer-col a{font-size:13px;color:#888;display:block;margin-bottom:8px;line-height:1.6}
.footer-col a:hover{color:#E94560}
.footer-qr{display:flex;gap:20px;margin-top:15px}
.footer-qr img{width:100px;height:100px;border-radius:8px;border:1px solid rgba(233,69,96,.15)}
.footer-qr-label{font-size:12px;color:#666;text-align:center;margin-top:5px}
.footer-bottom{border-top:1px solid rgba(233,69,96,.1);padding:20px 0;text-align:center;font-size:13px;color:#666}
.footer-bottom a{color:#888}

/* === 内页通用 === */
.page-hero{background:linear-gradient(135deg,#1A1A2E,#16213E);padding:100px 0 40px;text-align:center}
.page-hero h1{font-size:36px;margin-bottom:10px}
.page-hero p{color:#999;font-size:15px}
.page-content{padding:40px 0 60px}

/* === 社区帖子 === */
.post-list{display:flex;flex-direction:column;gap:16px}
.post-item{background:#1a1a3e;border-radius:10px;padding:20px;border:1px solid rgba(233,69,96,.08);transition:all .3s}
.post-item:hover{border-color:rgba(233,69,96,.2)}
.post-item h3{font-size:16px;margin-bottom:8px}
.post-item p{font-size:14px;color:#999;line-height:1.7}
.post-meta{display:flex;gap:15px;margin-top:10px;font-size:12px;color:#777}

/* === 工具卡片 === */
.tool-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:24px}
.tool-card{background:#1a1a3e;border-radius:12px;padding:30px;border:1px solid rgba(233,69,96,.08);transition:all .3s}
.tool-card:hover{border-color:rgba(233,69,96,.3);transform:translateY(-3px)}
.tool-card h3{font-size:18px;margin-bottom:10px;color:#E94560}
.tool-card p{font-size:14px;color:#999;line-height:1.7}

/* === 按钮通用 === */
.btn-primary{display:inline-block;padding:12px 30px;background:linear-gradient(135deg,#C41E3A,#E94560);color:#fff;border-radius:25px;font-size:14px;font-weight:600;transition:all .3s;border:none;cursor:pointer}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 4px 15px rgba(233,69,96,.4);color:#fff}
.btn-outline{display:inline-block;padding:12px 30px;border:1px solid #E94560;color:#E94560;border-radius:25px;font-size:14px;font-weight:600;transition:all .3s;background:transparent;cursor:pointer}
.btn-outline:hover{background:#E94560;color:#fff}

/* === 标签云 === */
.tag-cloud{display:flex;flex-wrap:wrap;gap:8px;margin:20px 0}
.tag-cloud a{padding:5px 14px;background:rgba(233,69,96,.1);border:1px solid rgba(233,69,96,.2);border-radius:15px;font-size:13px;color:#E94560;transition:all .3s}
.tag-cloud a:hover{background:#E94560;color:#fff}

/* === 数据统计条 === */
.stats-bar{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;padding:40px 0}
.stat-item{text-align:center}
.stat-num{font-size:36px;font-weight:800;color:#E94560;display:block}
.stat-label{font-size:14px;color:#999;margin-top:5px}

/* === 懒加载占位 === */
.lazy-img{background:#1a1a3e;min-height:200px}

/* === 干扰标签隐藏 === */
.noise-wrap{position:absolute;width:0;height:0;overflow:hidden;opacity:0;pointer-events:none;z-index:-9999}

/* === 响应式 === */
@media(max-width:768px){
  .main-nav{display:none;position:fixed;top:62px;left:0;width:100%;background:#0d0d1a;flex-direction:column;padding:20px;border-top:1px solid rgba(233,69,96,.2)}
  .main-nav.active{display:flex}
  .main-nav a{padding:12px 0;border-bottom:1px solid rgba(233,69,96,.08)}
  .menu-toggle{display:flex}
  .hero-content h1{font-size:28px}
  .hero-content p{font-size:16px}
  .section-title h2{font-size:24px}
  .video-grid{grid-template-columns:1fr}
  .feature-grid{grid-template-columns:1fr}
  .expert-grid{grid-template-columns:1fr}
  .stats-bar{grid-template-columns:repeat(2,1fr)}
  .footer-grid{grid-template-columns:1fr}
  .search-box{max-width:100%}
  .header-inner{padding:10px 15px}
  .hero-section{height:60vh;min-height:400px}
  .section-wrap{padding:40px 0}
  .contact-grid{grid-template-columns:1fr}
  .review-grid{grid-template-columns:1fr}
  .howto-steps{grid-template-columns:1fr 1fr}
}
@media(max-width:480px){
  .howto-steps{grid-template-columns:1fr}
  .stats-bar{grid-template-columns:1fr 1fr}
  .brand-wall .brand-item{width:100px;height:50px;font-size:12px}
  .hero-section{height:50vh;min-height:350px}
}