/* ============================================
   国产视频修车改装视频社区 - 凯迪拉克风格CSS
   配色：黑金银 | 布局：左右交错卡片式
   ============================================ */
:root{--primary:#1a1a1a;--secondary:#c8a84e;--accent:#e8d48b;--dark:#0d0d0d;--light:#f5f0e1;--grey:#2a2a2a;--silver:#b8b8b8;--gold-gradient:linear-gradient(135deg,#c8a84e,#e8d48b,#c8a84e);--dark-gradient:linear-gradient(180deg,#0d0d0d,#1a1a1a,#2a2a2a);--card-shadow:0 8px 32px rgba(0,0,0,0.4);--radius:12px;--transition:all .3s ease}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;font-size:16px}
body{font-family:'Helvetica Neue',Arial,'PingFang SC','Microsoft YaHei',sans-serif;background:var(--primary);color:#e0e0e0;line-height:1.8;overflow-x:hidden}
a{color:var(--secondary);text-decoration:none;transition:var(--transition)}
a:hover{color:var(--accent)}
img{max-width:100%;height:auto;display:block}
.container{max-width:1200px;margin:0 auto;padding:0 20px}

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

/* === 顶部导航 === */
.top-nav{position:fixed;top:0;left:0;width:100%;z-index:1000;background:rgba(13,13,13,0.95);backdrop-filter:blur(12px);border-bottom:1px solid rgba(200,168,78,0.2);padding:0 30px;height:68px;display:flex;align-items:center;justify-content:space-between;transition:var(--transition)}
.nav-brand{display:flex;align-items:center;gap:12px}
.nav-brand img{height:42px;width:auto}
.nav-brand span{font-size:1.4rem;font-weight:700;color:var(--secondary);letter-spacing:2px}
.nav-links{display:flex;gap:28px;list-style:none}
.nav-links a{color:#ccc;font-size:.95rem;font-weight:500;padding:8px 0;position:relative}
.nav-links a::after{content:'';position:absolute;bottom:0;left:0;width:0;height:2px;background:var(--secondary);transition:var(--transition)}
.nav-links a:hover::after,.nav-links a.active::after{width:100%}
.nav-links a:hover{color:var(--secondary)}
.mobile-toggle{display:none;flex-direction:column;gap:5px;cursor:pointer;padding:8px}
.mobile-toggle span{width:24px;height:2px;background:var(--secondary);transition:var(--transition)}

/* === 搜索框 === */
.search-bar{background:var(--grey);padding:12px 0;margin-top:68px}
.search-bar .container{display:flex;justify-content:center}
.search-box{display:flex;max-width:560px;width:100%}
.search-box input{flex:1;padding:10px 18px;border:1px solid rgba(200,168,78,0.3);border-right:none;border-radius:var(--radius) 0 0 var(--radius);background:rgba(26,26,26,0.8);color:#e0e0e0;font-size:.95rem;outline:none;transition:var(--transition)}
.search-box input:focus{border-color:var(--secondary)}
.search-box button{padding:10px 24px;background:var(--gold-gradient);border:none;border-radius:0 var(--radius) var(--radius) 0;color:var(--dark);font-weight:600;cursor:pointer;transition:var(--transition)}
.search-box button:hover{opacity:.85}

/* === Banner === */
.hero-banner{position:relative;height:520px;overflow:hidden;display:flex;align-items:center;justify-content:center;text-align:center}
.hero-banner img{position:absolute;top:0;left:0;width:100%;height:100%;object-fit:cover;filter:brightness(0.4)}
.hero-content{position:relative;z-index:2;max-width:800px;padding:0 20px}
.hero-content h1{font-size:2.8rem;color:#fff;margin-bottom:16px;text-shadow:0 4px 20px rgba(0,0,0,0.6)}
.hero-content h1 em{font-style:normal;color:var(--secondary)}
.hero-content p{font-size:1.15rem;color:rgba(255,255,255,0.85);margin-bottom:24px;line-height:1.8}
.hero-stats{display:flex;gap:40px;justify-content:center;margin-top:20px}
.stat-item{text-align:center}
.stat-num{font-size:2rem;font-weight:700;color:var(--secondary);display:block}
.stat-label{font-size:.85rem;color:rgba(255,255,255,0.7)}

/* === 通用模块标题 === */
.section{padding:60px 0}
.section-dark{background:var(--dark)}
.section-grey{background:var(--grey)}
.section-title{text-align:center;margin-bottom:40px}
.section-title h2{font-size:2rem;color:#fff;margin-bottom:10px;position:relative;display:inline-block}
.section-title h2::after{content:'';display:block;width:60px;height:3px;background:var(--gold-gradient);margin:12px auto 0}
.section-title p{color:var(--silver);font-size:1rem;margin-top:8px}

/* === 视频卡片网格 === */
.video-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.video-card{background:var(--grey);border-radius:var(--radius);overflow:hidden;box-shadow:var(--card-shadow);transition:var(--transition);position:relative;cursor:pointer}
.video-card:hover{transform:translateY(-6px);box-shadow:0 12px 40px rgba(200,168,78,0.15)}
.video-thumb{position:relative;padding-top:56.25%;overflow:hidden}
.video-thumb img{position:absolute;top:0;left:0;width:100%;height:100%;object-fit:cover;transition:var(--transition)}
.video-thumb video{position:absolute;top:0;left:0;width:100%;height:100%;object-fit:cover;opacity:0}
.video-card:hover .video-thumb img{transform:scale(1.05)}
.play-btn{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);width:56px;height:56px;background:rgba(200,168,78,0.9);border-radius:50%;display:flex;align-items:center;justify-content:center;opacity:0;transition:var(--transition);z-index:3}
.play-btn::after{content:'';width:0;height:0;border-style:solid;border-width:10px 0 10px 18px;border-color:transparent transparent transparent var(--dark);margin-left:4px}
.video-card:hover .play-btn{opacity:1}
.video-duration{position:absolute;bottom:8px;right:8px;background:rgba(0,0,0,0.8);color:#fff;padding:2px 8px;border-radius:4px;font-size:.8rem;z-index:3}
.video-info{padding:14px 16px}
.video-info h3{font-size:1rem;color:#e0e0e0;margin-bottom:6px;line-height:1.5;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.video-meta{display:flex;gap:14px;font-size:.8rem;color:var(--silver)}

/* === 左右交错布局 === */
.alt-layout{display:flex;gap:40px;align-items:center;margin-bottom:50px}
.alt-layout.reverse{flex-direction:row-reverse}
.alt-layout .alt-img{flex:1;border-radius:var(--radius);overflow:hidden}
.alt-layout .alt-img img{width:100%;border-radius:var(--radius);transition:var(--transition)}
.alt-layout .alt-img:hover img{transform:scale(1.03)}
.alt-layout .alt-text{flex:1}
.alt-layout .alt-text h3{font-size:1.5rem;color:var(--secondary);margin-bottom:12px}
.alt-layout .alt-text p{color:#bbb;line-height:1.9}

/* === 分类卡片 === */
.category-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.category-card{background:var(--grey);border:1px solid rgba(200,168,78,0.15);border-radius:var(--radius);padding:28px 20px;text-align:center;transition:var(--transition);display:block}
.category-card:hover{border-color:var(--secondary);transform:translateY(-4px);box-shadow:0 8px 24px rgba(200,168,78,0.1)}
.cat-icon{font-size:2.2rem;margin-bottom:12px}
.category-card h3{color:#e0e0e0;font-size:1rem;margin-bottom:6px}
.category-card p{color:var(--silver);font-size:.85rem}

/* === 专家卡片 === */
.expert-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:28px}
.expert-card{background:var(--grey);border-radius:var(--radius);padding:30px;text-align:center;border:1px solid rgba(200,168,78,0.1);transition:var(--transition)}
.expert-card:hover{border-color:var(--secondary);box-shadow:0 8px 30px rgba(200,168,78,0.1)}
.expert-avatar{width:90px;height:90px;border-radius:50%;background:var(--gold-gradient);margin:0 auto 16px;display:flex;align-items:center;justify-content:center;font-size:2rem;color:var(--dark);font-weight:700}
.expert-name{font-size:1.15rem;color:#fff;margin-bottom:4px}
.expert-role{color:var(--secondary);font-size:.9rem;margin-bottom:10px}
.expert-desc{color:var(--silver);font-size:.85rem;line-height:1.7}
.expert-links{margin-top:14px;display:flex;gap:10px;justify-content:center}
.expert-links a{padding:6px 16px;border:1px solid var(--secondary);border-radius:20px;color:var(--secondary);font-size:.8rem;transition:var(--transition)}
.expert-links a:hover{background:var(--secondary);color:var(--dark)}

/* === FAQ === */
.faq-list{max-width:800px;margin:0 auto}
.faq-item{border-bottom:1px solid rgba(200,168,78,0.15);padding:18px 0}
.faq-q{font-size:1.05rem;color:#e0e0e0;cursor:pointer;display:flex;justify-content:space-between;align-items:center;font-weight:600}
.faq-q::after{content:'+';font-size:1.4rem;color:var(--secondary);transition:var(--transition)}
.faq-item.open .faq-q::after{content:'-';transform:rotate(180deg)}
.faq-a{color:var(--silver);font-size:.95rem;line-height:1.8;max-height:0;overflow:hidden;transition:max-height .4s ease;padding-top:0}
.faq-item.open .faq-a{max-height:300px;padding-top:12px}

/* === 评价 === */
.review-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:24px}
.review-card{background:var(--grey);border-radius:var(--radius);padding:24px;border-left:3px solid var(--secondary)}
.review-card p{color:#ccc;font-size:.95rem;line-height:1.8;font-style:italic;margin-bottom:10px}
.reviewer{color:var(--secondary);font-size:.85rem;font-weight:600}
.review-stars{color:var(--secondary);margin-bottom:8px;font-size:1.1rem}

/* === HowTo === */
.howto-steps{max-width:700px;margin:0 auto}
.howto-step{display:flex;gap:20px;margin-bottom:28px;align-items:flex-start}
.step-num{width:44px;height:44px;min-width:44px;border-radius:50%;background:var(--gold-gradient);color:var(--dark);font-weight:700;font-size:1.2rem;display:flex;align-items:center;justify-content:center}
.step-content h3{color:#e0e0e0;font-size:1.05rem;margin-bottom:4px}
.step-content p{color:var(--silver);font-size:.9rem}

/* === 品牌墙 === */
.brand-wall{display:flex;flex-wrap:wrap;gap:20px;justify-content:center}
.brand-wall .brand-item{background:var(--grey);border:1px solid rgba(200,168,78,0.15);border-radius:8px;padding:16px 28px;color:var(--silver);font-weight:600;font-size:.95rem;transition:var(--transition)}
.brand-wall .brand-item:hover{border-color:var(--secondary);color:var(--secondary)}

/* === 联系模块 === */
.contact-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:30px}
.contact-info{background:var(--grey);border-radius:var(--radius);padding:30px}
.contact-info h3{color:var(--secondary);margin-bottom:16px;font-size:1.2rem}
.contact-info p{color:#ccc;margin-bottom:10px;font-size:.95rem}
.contact-qr{text-align:center}
.contact-qr img{max-width:200px;margin:0 auto 10px;border-radius:8px}
.contact-qr p{color:var(--silver);font-size:.85rem}

/* === 社交分享 === */
.share-bar{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.share-btn{padding:10px 22px;border-radius:24px;font-size:.9rem;font-weight:600;transition:var(--transition);border:1px solid rgba(200,168,78,0.3);color:#ccc;background:var(--grey)}
.share-btn:hover{background:var(--secondary);color:var(--dark);border-color:var(--secondary)}

/* === 页脚 === */
.site-footer{background:var(--dark);border-top:1px solid rgba(200,168,78,0.2);padding:50px 0 20px}
.footer-top{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:30px;margin-bottom:30px}
.footer-brand img{height:40px;margin-bottom:12px}
.footer-brand p{color:var(--silver);font-size:.85rem;line-height:1.7}
.footer-col h4{color:var(--secondary);font-size:1rem;margin-bottom:14px}
.footer-col a{display:block;color:var(--silver);font-size:.85rem;margin-bottom:8px;transition:var(--transition)}
.footer-col a:hover{color:var(--secondary)}
.footer-bottom{border-top:1px solid rgba(200,168,78,0.1);padding-top:20px;text-align:center;color:var(--silver);font-size:.8rem}
.footer-bottom a{color:var(--secondary)}

/* === 内页面包屑 === */
.breadcrumb{padding:12px 0;font-size:.85rem;color:var(--silver)}
.breadcrumb a{color:var(--secondary)}
.breadcrumb span{margin:0 6px;color:#666}

/* === 内页文章 === */
.article-meta{display:flex;gap:20px;color:var(--silver);font-size:.85rem;margin-bottom:20px;flex-wrap:wrap}
.article-content{color:#ccc;line-height:2}
.article-content h2{color:var(--secondary);font-size:1.5rem;margin:30px 0 15px}
.article-content h3{color:#e0e0e0;font-size:1.2rem;margin:20px 0 10px}
.article-content p{margin-bottom:16px}

/* === 响应式 === */
@media(max-width:1024px){
  .video-grid{grid-template-columns:repeat(2,1fr)}
  .category-grid{grid-template-columns:repeat(2,1fr)}
  .expert-grid{grid-template-columns:repeat(2,1fr)}
  .footer-top{grid-template-columns:1fr 1fr}
  .alt-layout{flex-direction:column}
  .alt-layout.reverse{flex-direction:column}
}
@media(max-width:768px){
  .top-nav{padding:0 16px}
  .nav-links{display:none;position:absolute;top:68px;left:0;width:100%;background:rgba(13,13,13,0.98);flex-direction:column;padding:20px;gap:0}
  .nav-links.open{display:flex}
  .nav-links a{padding:12px 0;border-bottom:1px solid rgba(200,168,78,0.1)}
  .mobile-toggle{display:flex}
  .hero-banner{height:400px}
  .hero-content h1{font-size:1.8rem}
  .hero-stats{gap:20px}
  .stat-num{font-size:1.4rem}
  .video-grid{grid-template-columns:1fr}
  .category-grid{grid-template-columns:repeat(2,1fr)}
  .expert-grid{grid-template-columns:1fr}
  .review-grid{grid-template-columns:1fr}
  .contact-grid{grid-template-columns:1fr}
  .footer-top{grid-template-columns:1fr}
  .section{padding:40px 0}
  .section-title h2{font-size:1.5rem}
}
@media(max-width:480px){
  .category-grid{grid-template-columns:1fr}
  .hero-banner{height:320px}
  .hero-content h1{font-size:1.4rem}
  .search-box input{padding:8px 12px}
}