/* ============================================
   91 修车改装视频社区 - 原创样式表
   配色方案：深蓝 #0a1628 / 电光蓝 #1e90ff / 活力橙 #ff6b2b / 钛灰 #2d3748 / 亮白 #f7fafc
   ============================================ */

/* === 基础重置 === */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;font-size:16px}
body{font-family:"PingFang SC","Hiragino Sans GB","Microsoft YaHei","WenQuanYi Micro Hei",sans-serif;color:#e2e8f0;background:#0a1628;line-height:1.7;overflow-x:hidden}
a{color:#1e90ff;text-decoration:none;transition:color .3s}
a:hover{color:#ff6b2b}
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:#f7fafc}

/* === 容器 === */
.container{max-width:1200px;margin:0 auto;padding:0 20px}
.section{padding:60px 0}
.section-title{text-align:center;margin-bottom:40px}
.section-title h2{font-size:2rem;color:#f7fafc;position:relative;display:inline-block;padding-bottom:12px}
.section-title h2::after{content:"";position:absolute;bottom:0;left:50%;transform:translateX(-50%);width:60px;height:3px;background:linear-gradient(90deg,#1e90ff,#ff6b2b);border-radius:2px}
.section-title p{color:#94a3b8;margin-top:10px;font-size:1rem}

/* === 头部导航 === */
.site-header{position:fixed;top:0;left:0;width:100%;z-index:1000;background:rgba(10,22,40,.95);backdrop-filter:blur(10px);border-bottom:1px solid rgba(30,144,255,.15);transition:all .3s}
.header-inner{display:flex;align-items:center;justify-content:space-between;height:70px}
.logo{display:flex;align-items:center;gap:10px}
.logo img{height:46px;width:auto}
.logo span{font-size:1.4rem;font-weight:800;color:#f7fafc;letter-spacing:1px}
.main-nav{display:flex;align-items:center;gap:0}
.main-nav a{padding:8px 18px;font-size:.95rem;color:#cbd5e1;transition:all .3s;border-radius:6px}
.main-nav a:hover,.main-nav a.active{color:#1e90ff;background:rgba(30,144,255,.1)}
.nav-toggle{display:none;flex-direction:column;gap:5px;cursor:pointer;padding:8px}
.nav-toggle span{width:24px;height:2px;background:#f7fafc;transition:all .3s}

/* === 搜索框 === */
.search-bar{background:rgba(30,144,255,.05);border-bottom:1px solid rgba(30,144,255,.1);padding:12px 0;margin-top:70px}
.search-wrap{display:flex;max-width:600px;margin:0 auto}
.search-wrap input{flex:1;padding:10px 18px;border:1px solid rgba(30,144,255,.3);border-right:none;border-radius:8px 0 0 8px;background:rgba(10,22,40,.8);color:#f7fafc;font-size:.95rem;outline:none;transition:border-color .3s}
.search-wrap input:focus{border-color:#1e90ff}
.search-wrap input::placeholder{color:#64748b}
.search-wrap button{padding:10px 24px;background:linear-gradient(135deg,#1e90ff,#0066cc);color:#fff;border:none;border-radius:0 8px 8px 0;cursor:pointer;font-size:.95rem;transition:opacity .3s}
.search-wrap button:hover{opacity:.85}

/* === Banner === */
.hero-banner{position:relative;height:520px;overflow:hidden;display:flex;align-items:center;justify-content:center}
.hero-banner .bg{position:absolute;inset:0;background-size:cover;background-position:center;filter:brightness(.45)}
.hero-banner .overlay{position:absolute;inset:0;background:linear-gradient(180deg,rgba(10,22,40,.3) 0%,rgba(10,22,40,.85) 100%)}
.hero-content{position:relative;z-index:2;text-align:center;max-width:800px;padding:0 20px}
.hero-content h1{font-size:2.8rem;margin-bottom:16px;background:linear-gradient(135deg,#1e90ff,#ff6b2b);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.hero-content p{font-size:1.15rem;color:#cbd5e1;margin-bottom:24px;line-height:1.8}
.hero-btns{display:flex;gap:16px;justify-content:center;flex-wrap:wrap}
.btn-primary{display:inline-block;padding:12px 32px;background:linear-gradient(135deg,#1e90ff,#0066cc);color:#fff;border-radius:8px;font-weight:600;transition:all .3s;border:none;cursor:pointer;font-size:1rem}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 8px 25px rgba(30,144,255,.35);color:#fff}
.btn-outline{display:inline-block;padding:12px 32px;border:2px solid #ff6b2b;color:#ff6b2b;border-radius:8px;font-weight:600;transition:all .3s;cursor:pointer;font-size:1rem;background:transparent}
.btn-outline:hover{background:#ff6b2b;color:#fff;transform:translateY(-2px)}

/* === 视频卡片网格 === */
.video-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:24px}
.video-card{position:relative;border-radius:12px;overflow:hidden;background:#1a2744;transition:all .4s;cursor:pointer}
.video-card:hover{transform:translateY(-6px);box-shadow:0 12px 40px rgba(30,144,255,.2)}
.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(1.08)}
.play-btn{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%) scale(0);width:64px;height:64px;background:rgba(30,144,255,.9);border-radius:50%;display:flex;align-items:center;justify-content:center;transition:all .4s;opacity:0}
.play-btn::after{content:"";width:0;height:0;border-style:solid;border-width:12px 0 12px 22px;border-color:transparent transparent transparent #fff;margin-left:4px}
.video-card:hover .play-btn{transform:translate(-50%,-50%) scale(1);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:.8rem}
.video-info{padding:16px}
.video-info h3{font-size:1rem;color:#f7fafc;margin-bottom:8px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.video-meta{display:flex;gap:16px;color:#64748b;font-size:.85rem}
.video-meta span{display:flex;align-items:center;gap:4px}
.video-tags{display:flex;gap:6px;margin-top:10px;flex-wrap:wrap}
.video-tags span{padding:3px 10px;background:rgba(30,144,255,.12);color:#1e90ff;border-radius:20px;font-size:.75rem}

/* === 特色模块卡片 === */
.feature-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:24px}
.feature-card{background:linear-gradient(145deg,#1a2744,#0f1d35);border:1px solid rgba(30,144,255,.1);border-radius:14px;padding:32px 24px;text-align:center;transition:all .4s}
.feature-card:hover{border-color:rgba(30,144,255,.4);transform:translateY(-4px);box-shadow:0 8px 30px rgba(30,144,255,.12)}
.feature-icon{width:64px;height:64px;margin:0 auto 20px;background:linear-gradient(135deg,rgba(30,144,255,.15),rgba(255,107,43,.1));border-radius:16px;display:flex;align-items:center;justify-content:center;font-size:1.8rem}
.feature-card h3{font-size:1.1rem;margin-bottom:10px;color:#f7fafc}
.feature-card p{color:#94a3b8;font-size:.9rem;line-height:1.6}

/* === 专家展示 === */
.expert-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:28px}
.expert-card{background:#1a2744;border-radius:14px;overflow:hidden;transition:all .4s;border:1px solid rgba(30,144,255,.08)}
.expert-card:hover{transform:translateY(-4px);box-shadow:0 12px 35px rgba(30,144,255,.15);border-color:rgba(30,144,255,.3)}
.expert-photo{height:300px;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:1.15rem;color:#f7fafc;margin-bottom:4px}
.expert-info .role{color:#1e90ff;font-size:.9rem;margin-bottom:10px}
.expert-info p{color:#94a3b8;font-size:.88rem;line-height:1.6;margin-bottom:14px}
.expert-links{display:flex;gap:10px}
.expert-links a{padding:6px 16px;border-radius:6px;font-size:.85rem;transition:all .3s}
.expert-links .link-primary{background:rgba(30,144,255,.15);color:#1e90ff}
.expert-links .link-primary:hover{background:#1e90ff;color:#fff}
.expert-links .link-secondary{background:rgba(255,107,43,.12);color:#ff6b2b}
.expert-links .link-secondary:hover{background:#ff6b2b;color:#fff}

/* === 合作品牌墙 === */
.brand-wall{display:flex;flex-wrap:wrap;justify-content:center;gap:30px;align-items:center}
.brand-wall .brand-item{width:140px;height:70px;background:rgba(30,144,255,.06);border:1px solid rgba(30,144,255,.1);border-radius:10px;display:flex;align-items:center;justify-content:center;color:#64748b;font-size:.9rem;font-weight:600;transition:all .3s}
.brand-wall .brand-item:hover{border-color:#1e90ff;color:#1e90ff;background:rgba(30,144,255,.1)}

/* === FAQ === */
.faq-list{max-width:800px;margin:0 auto}
.faq-item{border:1px solid rgba(30,144,255,.1);border-radius:10px;margin-bottom:12px;overflow:hidden;background:#1a2744}
.faq-question{padding:18px 24px;cursor:pointer;display:flex;justify-content:space-between;align-items:center;font-weight:600;color:#f7fafc;transition:background .3s}
.faq-question:hover{background:rgba(30,144,255,.06)}
.faq-question .arrow{transition:transform .3s;color:#1e90ff;font-size:1.2rem}
.faq-item.active .faq-question .arrow{transform:rotate(180deg)}
.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{color:#94a3b8;line-height:1.7;font-size:.95rem}

/* === 用户评论 === */
.review-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:24px}
.review-card{background:#1a2744;border-radius:12px;padding:24px;border:1px solid rgba(30,144,255,.08);transition:all .3s}
.review-card:hover{border-color:rgba(30,144,255,.25)}
.review-stars{color:#ff6b2b;margin-bottom:10px;font-size:1rem;letter-spacing:2px}
.review-text{color:#cbd5e1;font-size:.95rem;line-height:1.7;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,#1e90ff,#ff6b2b);display:flex;align-items:center;justify-content:center;color:#fff;font-weight:700;font-size:.9rem}
.review-name{color:#f7fafc;font-size:.9rem;font-weight:600}
.review-date{color:#64748b;font-size:.8rem}

/* === 联系我们 === */
.contact-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:24px}
.contact-card{background:#1a2744;border-radius:12px;padding:28px;text-align:center;border:1px solid rgba(30,144,255,.08)}
.contact-card h4{color:#f7fafc;margin-bottom:8px;font-size:1.05rem}
.contact-card p{color:#94a3b8;font-size:.9rem;line-height:1.6}
.contact-card .highlight{color:#1e90ff;font-weight:600}

/* === 页脚 === */
.site-footer{background:#060e1a;border-top:1px solid rgba(30,144,255,.1);padding:50px 0 20px}
.footer-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:30px;margin-bottom:30px}
.footer-col h4{color:#f7fafc;font-size:1rem;margin-bottom:16px;position:relative;padding-bottom:10px}
.footer-col h4::after{content:"";position:absolute;bottom:0;left:0;width:30px;height:2px;background:#1e90ff}
.footer-col p,.footer-col a{color:#64748b;font-size:.88rem;line-height:2}
.footer-col a:hover{color:#1e90ff}
.footer-qr{display:flex;gap:20px;margin-top:10px}
.footer-qr img{width:100px;height:100px;border-radius:8px;border:1px solid rgba(30,144,255,.15)}
.footer-qr-label{text-align:center;color:#64748b;font-size:.78rem;margin-top:4px}
.footer-bottom{border-top:1px solid rgba(30,144,255,.08);padding-top:20px;text-align:center;color:#475569;font-size:.85rem}
.footer-bottom a{color:#1e90ff}
.share-links{display:flex;gap:12px;justify-content:center;margin-top:12px;flex-wrap:wrap}
.share-links a{width:38px;height:38px;border-radius:50%;background:rgba(30,144,255,.1);display:flex;align-items:center;justify-content:center;color:#1e90ff;font-size:.85rem;transition:all .3s;border:1px solid rgba(30,144,255,.15)}
.share-links a:hover{background:#1e90ff;color:#fff}

/* === 面包屑 === */
.breadcrumb{padding:14px 0;color:#64748b;font-size:.88rem}
.breadcrumb a{color:#1e90ff}
.breadcrumb span{margin:0 8px;color:#475569}

/* === 内页通用 === */
.page-hero{padding:100px 0 40px;background:linear-gradient(180deg,rgba(30,144,255,.08),transparent)}
.page-hero h1{font-size:2.2rem;text-align:center;margin-bottom:10px}
.page-hero p{text-align:center;color:#94a3b8;max-width:600px;margin:0 auto}

/* === AI赋能模块 === */
.ai-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(340px,1fr));gap:24px}
.ai-card{background:linear-gradient(145deg,#1a2744,#0f1d35);border:1px solid rgba(30,144,255,.12);border-radius:14px;padding:28px;transition:all .4s}
.ai-card:hover{border-color:rgba(255,107,43,.3);box-shadow:0 8px 30px rgba(255,107,43,.1)}
.ai-card h3{color:#ff6b2b;margin-bottom:10px;font-size:1.1rem}
.ai-card p{color:#94a3b8;font-size:.92rem;line-height:1.7}

/* === 社区模块 === */
.community-tabs{display:flex;gap:10px;justify-content:center;margin-bottom:30px;flex-wrap:wrap}
.community-tabs .tab{padding:8px 22px;border-radius:20px;background:rgba(30,144,255,.08);color:#94a3b8;cursor:pointer;transition:all .3s;font-size:.9rem}
.community-tabs .tab.active,.community-tabs .tab:hover{background:#1e90ff;color:#fff}

/* === How-To指南 === */
.howto-steps{max-width:700px;margin:0 auto}
.howto-step{display:flex;gap:20px;margin-bottom:28px;align-items:flex-start}
.step-num{flex-shrink:0;width:44px;height:44px;border-radius:50%;background:linear-gradient(135deg,#1e90ff,#0066cc);display:flex;align-items:center;justify-content:center;color:#fff;font-weight:700;font-size:1.1rem}
.step-content h4{color:#f7fafc;margin-bottom:6px}
.step-content p{color:#94a3b8;font-size:.92rem}

/* === 懒加载占位 === */
.lazy{opacity:0;transition:opacity .6s}
.lazy.loaded{opacity:1}

/* === 响应式 === */
@media(max-width:768px){
  .header-inner{padding:0 16px}
  .main-nav{position:fixed;top:70px;left:0;width:100%;background:rgba(10,22,40,.98);flex-direction:column;padding:20px;transform:translateY(-120%);transition:transform .3s;gap:4px}
  .main-nav.open{transform:translateY(0)}
  .main-nav a{padding:12px 16px;width:100%}
  .nav-toggle{display:flex}
  .hero-banner{height:400px}
  .hero-content h1{font-size:1.8rem}
  .hero-content p{font-size:1rem}
  .video-grid{grid-template-columns:1fr}
  .feature-grid{grid-template-columns:1fr 1fr}
  .expert-grid{grid-template-columns:1fr}
  .section{padding:40px 0}
  .section-title h2{font-size:1.5rem}
  .footer-grid{grid-template-columns:1fr 1fr}
  .ai-grid{grid-template-columns:1fr}
  .hero-btns{flex-direction:column;align-items:center}
}
@media(max-width:480px){
  .feature-grid{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr}
  .review-grid{grid-template-columns:1fr}
  .contact-grid{grid-template-columns:1fr}
  .brand-wall .brand-item{width:110px;height:55px;font-size:.8rem}
}