/* ============================================
   91 修车改装视频社区 - 原创样式表
   配色：赛车红 #E31937 / 钛金灰 #2D2D2D / 亮橙 #FF6B00 / 冰蓝 #00B4D8 / 深碳黑 #111111
   ============================================ */

/* === Reset & Base === */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{font-size:16px;scroll-behavior:smooth}
body{font-family:"PingFang SC","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;color:#e0e0e0;background:#111111;line-height:1.7}
a{color:#00B4D8;text-decoration:none;transition:color .3s}
a:hover{color:#FF6B00}
img{max-width:100%;height:auto;display:block}
ul,ol{list-style:none}

/* === Container === */
.container{max-width:1280px;margin:0 auto;padding:0 20px}

/* === Header / Nav === */
.site-header{background:linear-gradient(180deg,#1a1a1a 0%,#111111 100%);position:sticky;top:0;z-index:1000;border-bottom:2px solid #E31937;padding:0}
.nav-wrap{display:flex;align-items:center;justify-content:space-between;height:68px}
.nav-logo{display:flex;align-items:center;gap:10px}
.nav-logo img{height:42px;width:auto}
.nav-logo span{font-size:1.4rem;font-weight:700;color:#fff;letter-spacing:1px}
.nav-menu{display:flex;gap:6px;align-items:center}
.nav-menu a{color:#ccc;font-size:.95rem;padding:8px 14px;border-radius:6px;transition:all .3s;font-weight:500}
.nav-menu a:hover,.nav-menu a.active{color:#fff;background:rgba(227,25,55,.15)}
.nav-toggle{display:none;flex-direction:column;gap:5px;cursor:pointer;padding:8px}
.nav-toggle span{width:26px;height:3px;background:#fff;border-radius:2px;transition:.3s}

/* === Search Bar === */
.search-bar{background:#1a1a1a;padding:12px 0;border-bottom:1px solid #222}
.search-box{display:flex;max-width:600px;margin:0 auto}
.search-box input{flex:1;padding:10px 18px;border:2px solid #333;border-right:none;border-radius:25px 0 0 25px;background:#222;color:#fff;font-size:.95rem;outline:none;transition:border-color .3s}
.search-box input:focus{border-color:#E31937}
.search-box button{padding:10px 24px;background:linear-gradient(135deg,#E31937,#FF6B00);color:#fff;border:none;border-radius:0 25px 25px 0;cursor:pointer;font-size:.95rem;font-weight:600;transition:opacity .3s}
.search-box button:hover{opacity:.85}

/* === Hero Banner === */
.hero{position:relative;height:520px;overflow:hidden;display:flex;align-items:center;justify-content:center}
.hero-bg{position:absolute;inset:0;background-size:cover;background-position:center;filter:brightness(.45)}
.hero-content{position:relative;z-index:2;text-align:center;max-width:800px;padding:0 20px}
.hero h1{font-size:2.8rem;font-weight:800;color:#fff;margin-bottom:16px;text-shadow:0 2px 20px rgba(0,0,0,.6)}
.hero h1 em{font-style:normal;color:#E31937}
.hero p{font-size:1.15rem;color:#ddd;margin-bottom:24px;line-height:1.8}
.hero-tags{display:flex;flex-wrap:wrap;gap:10px;justify-content:center}
.hero-tags span{background:rgba(227,25,55,.2);border:1px solid rgba(227,25,55,.4);color:#ff8a9e;padding:6px 16px;border-radius:20px;font-size:.85rem}

/* === Section Common === */
.section{padding:60px 0}
.section-dark{background:#0a0a0a}
.section-alt{background:#151515}
.section-title{text-align:center;margin-bottom:40px}
.section-title h2{font-size:2rem;font-weight:700;color:#fff;margin-bottom:10px}
.section-title h2 em{font-style:normal;color:#E31937}
.section-title p{color:#999;font-size:1rem;max-width:600px;margin:0 auto}

/* === Video Card Grid === */
.video-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.video-card{background:#1a1a1a;border-radius:12px;overflow:hidden;transition:transform .3s,box-shadow .3s;cursor:pointer;position:relative}
.video-card:hover{transform:translateY(-6px);box-shadow:0 12px 40px rgba(227,25,55,.2)}
.video-thumb{position:relative;overflow:hidden;aspect-ratio:16/9}
.video-thumb img{width:100%;height:100%;object-fit:cover;transition:transform .4s}
.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:60px;height:60px;background:rgba(227,25,55,.9);border-radius:50%;display:flex;align-items:center;justify-content:center;transition:transform .3s;pointer-events:none}
.play-btn::after{content:"";width:0;height:0;border-left:22px solid #fff;border-top:13px solid transparent;border-bottom:13px solid transparent;margin-left:4px}
.video-card:hover .play-btn{transform:translate(-50%,-50%) scale(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:.75rem}
.video-info{padding:14px}
.video-info h3{font-size:.95rem;color:#fff;margin-bottom:8px;line-height:1.4;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.video-meta{display:flex;justify-content:space-between;color:#777;font-size:.8rem}
.video-meta span{display:flex;align-items:center;gap:4px}

/* === Category Tags === */
.cat-tags{display:flex;flex-wrap:wrap;gap:10px;justify-content:center;margin-bottom:30px}
.cat-tags a{background:#1a1a1a;color:#ccc;padding:8px 20px;border-radius:20px;font-size:.9rem;border:1px solid #333;transition:all .3s}
.cat-tags a:hover,.cat-tags a.active{background:#E31937;color:#fff;border-color:#E31937}

/* === Expert Cards === */
.expert-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
.expert-card{background:#1a1a1a;border-radius:12px;padding:28px 20px;text-align:center;transition:transform .3s,box-shadow .3s}
.expert-card:hover{transform:translateY(-4px);box-shadow:0 8px 30px rgba(0,180,216,.15)}
.expert-card img{width:100px;height:100px;border-radius:50%;object-fit:cover;margin:0 auto 16px;border:3px solid #E31937}
.expert-card h4{color:#fff;font-size:1.05rem;margin-bottom:6px}
.expert-card .role{color:#FF6B00;font-size:.85rem;margin-bottom:10px}
.expert-card p{color:#999;font-size:.85rem;line-height:1.6;margin-bottom:14px}
.expert-card .btn-sm{display:inline-block;padding:6px 18px;background:linear-gradient(135deg,#E31937,#FF6B00);color:#fff;border-radius:20px;font-size:.8rem;transition:opacity .3s}
.expert-card .btn-sm:hover{opacity:.8}

/* === FAQ === */
.faq-list{max-width:800px;margin:0 auto}
.faq-item{background:#1a1a1a;border-radius:10px;margin-bottom:12px;overflow:hidden;border:1px solid #222}
.faq-q{padding:18px 24px;cursor:pointer;display:flex;justify-content:space-between;align-items:center;color:#fff;font-weight:600;font-size:1rem;transition:background .3s}
.faq-q:hover{background:#222}
.faq-q::after{content:"+";font-size:1.4rem;color:#E31937;transition:transform .3s}
.faq-item.open .faq-q::after{transform:rotate(45deg)}
.faq-a{max-height:0;overflow:hidden;transition:max-height .4s ease,padding .4s;padding:0 24px;color:#aaa;font-size:.95rem;line-height:1.8}
.faq-item.open .faq-a{max-height:300px;padding:0 24px 18px}

/* === Reviews === */
.review-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:20px}
.review-card{background:#1a1a1a;border-radius:12px;padding:24px;border-left:4px solid #E31937}
.review-card .stars{color:#FF6B00;font-size:1.1rem;margin-bottom:10px}
.review-card p{color:#ccc;font-size:.95rem;line-height:1.7;margin-bottom:12px;font-style:italic}
.review-card .reviewer{display:flex;align-items:center;gap:10px;color:#999;font-size:.85rem}
.review-card .reviewer strong{color:#fff}

/* === How-To === */
.howto-steps{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;max-width:1000px;margin:0 auto}
.howto-step{text-align:center;padding:24px;background:#1a1a1a;border-radius:12px;position:relative}
.howto-step .step-num{width:48px;height:48px;background:linear-gradient(135deg,#E31937,#FF6B00);color:#fff;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:1.3rem;font-weight:700;margin:0 auto 14px}
.howto-step h4{color:#fff;margin-bottom:8px;font-size:1rem}
.howto-step p{color:#999;font-size:.85rem;line-height:1.6}

/* === Partner Logos === */
.partner-wall{display:flex;flex-wrap:wrap;gap:20px;justify-content:center;align-items:center}
.partner-wall .partner-item{background:#1a1a1a;padding:16px 28px;border-radius:10px;color:#999;font-size:.95rem;font-weight:600;border:1px solid #222;transition:all .3s}
.partner-wall .partner-item:hover{border-color:#E31937;color:#fff}

/* === Contact Section === */
.contact-grid{display:grid;grid-template-columns:1fr 1fr;gap:30px}
.contact-info{background:#1a1a1a;border-radius:12px;padding:30px}
.contact-info h3{color:#fff;font-size:1.3rem;margin-bottom:20px}
.contact-info .info-item{display:flex;gap:12px;margin-bottom:16px;color:#ccc;font-size:.95rem}
.contact-info .info-item strong{color:#FF6B00;min-width:80px}
.contact-qr{display:flex;gap:20px;justify-content:center;align-items:center}
.contact-qr .qr-item{text-align:center}
.contact-qr .qr-item img{width:140px;height:140px;border-radius:8px;margin-bottom:8px}
.contact-qr .qr-item span{color:#999;font-size:.85rem}

/* === Share Buttons === */
.share-bar{display:flex;gap:12px;justify-content:center;flex-wrap:wrap;padding:20px 0}
.share-btn{display:inline-flex;align-items:center;gap:6px;padding:8px 20px;border-radius:20px;color:#fff;font-size:.85rem;transition:opacity .3s;cursor:pointer}
.share-btn:hover{opacity:.8;color:#fff}
.share-btn.wechat{background:#07C160}
.share-btn.weibo{background:#E6162D}
.share-btn.douyin{background:#111;border:1px solid #333}
.share-btn.bilibili{background:#00A1D6}

/* === Footer === */
.site-footer{background:#0a0a0a;border-top:2px solid #E31937;padding:40px 0 20px}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:30px;margin-bottom:30px}
.footer-col h4{color:#fff;font-size:1rem;margin-bottom:16px;padding-bottom:8px;border-bottom:2px solid #E31937;display:inline-block}
.footer-col p{color:#888;font-size:.9rem;line-height:1.7;margin-bottom:8px}
.footer-col a{display:block;color:#888;font-size:.9rem;margin-bottom:8px;transition:color .3s}
.footer-col a:hover{color:#E31937}
.footer-col .footer-logo{display:flex;align-items:center;gap:10px;margin-bottom:14px}
.footer-col .footer-logo img{height:36px}
.footer-col .footer-logo span{color:#fff;font-size:1.2rem;font-weight:700}
.footer-bottom{text-align:center;padding-top:20px;border-top:1px solid #222;color:#666;font-size:.85rem}
.footer-bottom a{color:#888}

/* === Breadcrumb === */
.breadcrumb{padding:14px 0;font-size:.85rem;color:#777}
.breadcrumb a{color:#999}
.breadcrumb a:hover{color:#E31937}
.breadcrumb span{margin:0 6px;color:#555}

/* === Buttons === */
.btn-primary{display:inline-block;padding:12px 32px;background:linear-gradient(135deg,#E31937,#FF6B00);color:#fff;border-radius:25px;font-size:1rem;font-weight:600;transition:all .3s;border:none;cursor:pointer}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 6px 20px rgba(227,25,55,.4);color:#fff}
.btn-outline{display:inline-block;padding:10px 28px;border:2px solid #E31937;color:#E31937;border-radius:25px;font-size:.95rem;transition:all .3s}
.btn-outline:hover{background:#E31937;color:#fff}

/* === AI Module === */
.ai-features{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.ai-card{background:linear-gradient(145deg,#1a1a1a,#151515);border-radius:12px;padding:28px;border:1px solid #222;transition:all .3s}
.ai-card:hover{border-color:#00B4D8;box-shadow:0 0 20px rgba(0,180,216,.1)}
.ai-card .ai-icon{font-size:2.2rem;margin-bottom:14px}
.ai-card h4{color:#fff;font-size:1.1rem;margin-bottom:10px}
.ai-card p{color:#999;font-size:.9rem;line-height:1.7}

/* === Community Stats === */
.stats-bar{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;padding:30px 0}
.stat-item{text-align:center;padding:20px;background:#1a1a1a;border-radius:10px}
.stat-item .num{font-size:2.2rem;font-weight:800;background:linear-gradient(135deg,#E31937,#FF6B00);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.stat-item .label{color:#999;font-size:.9rem;margin-top:6px}

/* === Mobile Responsive === */
@media(max-width:1024px){
  .video-grid{grid-template-columns:repeat(3,1fr)}
  .expert-grid{grid-template-columns:repeat(2,1fr)}
  .footer-grid{grid-template-columns:1fr 1fr}
  .ai-features{grid-template-columns:repeat(2,1fr)}
  .howto-steps{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:768px){
  .nav-menu{display:none;position:absolute;top:68px;left:0;right:0;background:#1a1a1a;flex-direction:column;padding:20px;border-bottom:2px solid #E31937}
  .nav-menu.open{display:flex}
  .nav-toggle{display:flex}
  .hero{height:400px}
  .hero h1{font-size:1.8rem}
  .video-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-grid{grid-template-columns:1fr}
  .stats-bar{grid-template-columns:repeat(2,1fr)}
  .ai-features{grid-template-columns:1fr}
  .howto-steps{grid-template-columns:1fr}
  .section{padding:40px 0}
}
@media(max-width:480px){
  .video-grid{grid-template-columns:1fr}
  .hero{height:320px}
  .hero h1{font-size:1.5rem}
  .stats-bar{grid-template-columns:1fr}
}