/* ============================================
   91 修车改装视频社区 - 原创样式表
   配色：赛车红 #E31937 + 钢铁灰 #2C3E50 + 深黑 #0D0D0D
   字体：系统默认中文字体栈
   ============================================ */

/* === 基础重置与变量 === */
:root {
  --c-red: #E31937;
  --c-red-dark: #B8142D;
  --c-red-light: #FF3D5A;
  --c-gray: #2C3E50;
  --c-gray-light: #4A6274;
  --c-dark: #0D0D0D;
  --c-dark2: #1A1A1A;
  --c-dark3: #252525;
  --c-white: #F5F5F5;
  --c-text: #E0E0E0;
  --c-text-muted: #999;
  --c-gold: #D4A843;
  --c-border: #333;
  --font-main: "PingFang SC","Hiragino Sans GB","Microsoft YaHei","WenQuanYi Micro Hei",sans-serif;
  --shadow-card: 0 4px 20px rgba(0,0,0,.5);
  --shadow-hover: 0 8px 32px rgba(227,25,55,.3);
  --radius: 8px;
  --max-w: 1280px;
  --transition: .3s ease;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{font-size:16px;scroll-behavior:smooth}
body{font-family:var(--font-main);background:var(--c-dark);color:var(--c-text);line-height:1.7;overflow-x:hidden}
a{color:var(--c-red-light);text-decoration:none;transition:color var(--transition)}
a:hover{color:var(--c-gold)}
img{max-width:100%;height:auto;display:block}
ul,ol{list-style:none}
.wrap{max-width:var(--max-w);margin:0 auto;padding:0 20px}

/* === 顶部导航 === */
.site-header{background:linear-gradient(180deg,rgba(13,13,13,.98) 0%,rgba(26,26,26,.95) 100%);position:sticky;top:0;z-index:1000;border-bottom:2px solid var(--c-red);backdrop-filter:blur(10px)}
.nav-inner{display:flex;align-items:center;justify-content:space-between;max-width:var(--max-w);margin:0 auto;padding:0 20px;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:var(--c-white);letter-spacing:2px}
.nav-links{display:flex;gap:6px}
.nav-links a{color:var(--c-text);font-size:.92rem;padding:8px 14px;border-radius:var(--radius);transition:all var(--transition);position:relative}
.nav-links a:hover,.nav-links a.active{color:var(--c-white);background:var(--c-red)}
.nav-toggle{display:none;flex-direction:column;gap:5px;cursor:pointer;padding:8px}
.nav-toggle span{width:26px;height:3px;background:var(--c-white);border-radius:2px;transition:var(--transition)}

/* === 搜索框 === */
.search-bar{background:var(--c-dark2);padding:16px 0;border-bottom:1px solid var(--c-border)}
.search-wrap{max-width:640px;margin:0 auto;display:flex;gap:0}
.search-wrap input{flex:1;padding:12px 20px;border:2px solid var(--c-border);border-right:none;border-radius:var(--radius) 0 0 var(--radius);background:var(--c-dark3);color:var(--c-white);font-size:.95rem;outline:none;transition:border-color var(--transition)}
.search-wrap input:focus{border-color:var(--c-red)}
.search-wrap button{padding:12px 28px;background:var(--c-red);color:#fff;border:2px solid var(--c-red);border-radius:0 var(--radius) var(--radius) 0;font-size:.95rem;cursor:pointer;transition:background var(--transition);white-space:nowrap}
.search-wrap button:hover{background:var(--c-red-dark)}

/* === Hero Banner === */
.hero-section{position:relative;height:520px;overflow:hidden}
.hero-slide{position:absolute;inset:0;opacity:0;transition:opacity 1s ease}
.hero-slide.active{opacity:1}
.hero-slide img{width:100%;height:100%;object-fit:cover}
.hero-overlay{position:absolute;inset:0;background:linear-gradient(135deg,rgba(13,13,13,.85) 0%,rgba(227,25,55,.15) 50%,rgba(13,13,13,.7) 100%);display:flex;align-items:center;justify-content:center}
.hero-content{text-align:center;max-width:720px;padding:0 20px}
.hero-content h1{font-size:2.8rem;color:var(--c-white);margin-bottom:16px;text-shadow:0 2px 20px rgba(227,25,55,.5)}
.hero-content h1 em{font-style:normal;color:var(--c-red)}
.hero-content p{font-size:1.15rem;color:var(--c-text);margin-bottom:28px;line-height:1.8}
.hero-btns{display:flex;gap:16px;justify-content:center;flex-wrap:wrap}
.btn-primary{display:inline-block;padding:14px 36px;background:var(--c-red);color:#fff;border-radius:var(--radius);font-weight:600;font-size:1rem;transition:all var(--transition);border:2px solid var(--c-red)}
.btn-primary:hover{background:transparent;color:var(--c-red)}
.btn-outline{display:inline-block;padding:14px 36px;border:2px solid var(--c-gold);color:var(--c-gold);border-radius:var(--radius);font-weight:600;font-size:1rem;transition:all var(--transition)}
.btn-outline:hover{background:var(--c-gold);color:var(--c-dark)}

/* === 面包屑 === */
.breadcrumb{padding:14px 0;font-size:.85rem;color:var(--c-text-muted)}
.breadcrumb a{color:var(--c-text-muted)}
.breadcrumb a:hover{color:var(--c-red)}
.breadcrumb span{margin:0 6px}

/* === 通用区块 === */
.section{padding:60px 0}
.section-alt{background:var(--c-dark2)}
.section-title{text-align:center;margin-bottom:48px}
.section-title h2{font-size:2rem;color:var(--c-white);margin-bottom:10px;position:relative;display:inline-block}
.section-title h2::after{content:"";position:absolute;bottom:-8px;left:50%;transform:translateX(-50%);width:60px;height:3px;background:var(--c-red);border-radius:2px}
.section-title p{color:var(--c-text-muted);font-size:.95rem;margin-top:16px}

/* === 视频卡片网格 === */
.video-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.video-card{background:var(--c-dark2);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow-card);transition:all var(--transition);border:1px solid var(--c-border)}
.video-card:hover{transform:translateY(-6px);box-shadow:var(--shadow-hover);border-color:var(--c-red)}
.video-card .thumb{position:relative;padding-top:66.67%;overflow:hidden}
.video-card .thumb img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;transition:transform .5s ease}
.video-card:hover .thumb img{transform:scale(1.08)}
.video-card .play-btn{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%) scale(0);width:64px;height:64px;background:rgba(227,25,55,.9);border-radius:50%;display:flex;align-items:center;justify-content:center;transition:all .4s ease;cursor:pointer;z-index:2}
.video-card:hover .play-btn{transform:translate(-50%,-50%) scale(1)}
.video-card .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 .duration{position:absolute;bottom:10px;right:10px;background:rgba(0,0,0,.8);color:#fff;padding:3px 10px;border-radius:4px;font-size:.8rem;z-index:2}
.video-card .card-body{padding:16px}
.video-card .card-body h3{font-size:1rem;color:var(--c-white);margin-bottom:8px;line-height:1.5;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.video-card .meta{display:flex;gap:14px;font-size:.8rem;color:var(--c-text-muted);margin-bottom:10px}
.video-card .tags{display:flex;flex-wrap:wrap;gap:6px}
.video-card .tags span{padding:3px 10px;background:rgba(227,25,55,.15);color:var(--c-red-light);border-radius:20px;font-size:.75rem;border:1px solid rgba(227,25,55,.3)}

/* === 专家卡片 === */
.expert-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
.expert-card{background:var(--c-dark2);border-radius:var(--radius);padding:28px 20px;text-align:center;border:1px solid var(--c-border);transition:all var(--transition)}
.expert-card:hover{border-color:var(--c-red);box-shadow:var(--shadow-hover)}
.expert-card img{width:100px;height:100px;border-radius:50%;object-fit:cover;margin:0 auto 16px;border:3px solid var(--c-red)}
.expert-card h4{color:var(--c-white);font-size:1.05rem;margin-bottom:6px}
.expert-card .role{color:var(--c-gold);font-size:.85rem;margin-bottom:10px}
.expert-card p{font-size:.85rem;color:var(--c-text-muted);line-height:1.6;margin-bottom:14px}
.expert-card .expert-btns{display:flex;gap:8px;justify-content:center}
.expert-card .expert-btns a{padding:6px 16px;border-radius:20px;font-size:.8rem;border:1px solid var(--c-red);color:var(--c-red-light);transition:all var(--transition)}
.expert-card .expert-btns a:hover{background:var(--c-red);color:#fff}

/* === AI功能区 === */
.ai-block{display:grid;grid-template-columns:1fr 1fr;gap:40px;align-items:center}
.ai-block .ai-img{border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow-card)}
.ai-block .ai-img img{width:100%;transition:transform .5s ease}
.ai-block .ai-img:hover img{transform:scale(1.03)}
.ai-block .ai-text h3{font-size:1.5rem;color:var(--c-white);margin-bottom:16px}
.ai-block .ai-text p{margin-bottom:14px;color:var(--c-text)}
.ai-list{margin-top:20px}
.ai-list li{padding:10px 0;border-bottom:1px solid var(--c-border);color:var(--c-text);font-size:.92rem}
.ai-list li::before{content:"\2713";color:var(--c-red);margin-right:10px;font-weight:700}

/* === 合作品牌 === */
.partners-img{max-width:900px;margin:0 auto;border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow-card)}

/* === FAQ手风琴 === */
.faq-list{max-width:800px;margin:0 auto}
.faq-item{border:1px solid var(--c-border);border-radius:var(--radius);margin-bottom:12px;overflow:hidden;background:var(--c-dark2)}
.faq-q{padding:18px 24px;cursor:pointer;display:flex;justify-content:space-between;align-items:center;color:var(--c-white);font-weight:600;font-size:.95rem;transition:background var(--transition)}
.faq-q:hover{background:var(--c-dark3)}
.faq-q .arrow{font-size:1.2rem;transition:transform var(--transition);color:var(--c-red)}
.faq-item.open .faq-q .arrow{transform:rotate(180deg)}
.faq-a{max-height:0;overflow:hidden;transition:max-height .4s ease,padding .4s ease;padding:0 24px}
.faq-item.open .faq-a{max-height:300px;padding:0 24px 18px}
.faq-a p{color:var(--c-text-muted);font-size:.9rem;line-height:1.7}

/* === 评论区 === */
.review-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:24px}
.review-card{background:var(--c-dark2);border-radius:var(--radius);padding:24px;border:1px solid var(--c-border);transition:all var(--transition)}
.review-card:hover{border-color:var(--c-gold)}
.review-card .stars{color:var(--c-gold);font-size:1rem;margin-bottom:10px;letter-spacing:2px}
.review-card blockquote{font-size:.92rem;color:var(--c-text);line-height:1.7;margin-bottom:14px;font-style:italic}
.review-card .reviewer{display:flex;align-items:center;gap:10px}
.review-card .reviewer strong{color:var(--c-white);font-size:.9rem}
.review-card .reviewer span{color:var(--c-text-muted);font-size:.8rem}

/* === 社区功能 === */
.community-features{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.comm-card{background:var(--c-dark2);border-radius:var(--radius);padding:32px 24px;text-align:center;border:1px solid var(--c-border);transition:all var(--transition)}
.comm-card:hover{border-color:var(--c-red);transform:translateY(-4px)}
.comm-card .icon{font-size:2.5rem;margin-bottom:16px}
.comm-card h4{color:var(--c-white);font-size:1.05rem;margin-bottom:10px}
.comm-card p{color:var(--c-text-muted);font-size:.88rem;line-height:1.6}

/* === How-To指南 === */
.howto-steps{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;max-width:960px;margin:0 auto}
.step-card{text-align:center;padding:28px 16px}
.step-card .step-num{width:52px;height:52px;border-radius:50%;background:var(--c-red);color:#fff;font-size:1.4rem;font-weight:700;display:flex;align-items:center;justify-content:center;margin:0 auto 16px}
.step-card h4{color:var(--c-white);margin-bottom:8px;font-size:.95rem}
.step-card p{color:var(--c-text-muted);font-size:.85rem;line-height:1.6}

/* === 联系信息 === */
.contact-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:40px}
.contact-info h3{color:var(--c-white);font-size:1.3rem;margin-bottom:20px}
.contact-info p{margin-bottom:12px;color:var(--c-text);font-size:.92rem}
.contact-info p strong{color:var(--c-white)}
.qr-codes{display:flex;gap:24px;margin-top:20px}
.qr-codes .qr-item{text-align:center}
.qr-codes .qr-item img{width:140px;height:140px;border-radius:var(--radius);border:2px solid var(--c-border)}
.qr-codes .qr-item p{margin-top:8px;font-size:.82rem;color:var(--c-text-muted)}

/* === 社交分享 === */
.share-btns{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.share-btns a{display:inline-flex;align-items:center;gap:6px;padding:10px 20px;border-radius:var(--radius);font-size:.88rem;color:#fff;transition:all var(--transition)}
.share-btns .s-wechat{background:#07C160}
.share-btns .s-weibo{background:#E6162D}
.share-btns .s-douyin{background:#111;border:1px solid #333}
.share-btns .s-bilibili{background:#00A1D6}
.share-btns a:hover{opacity:.85;transform:translateY(-2px)}

/* === 页脚 === */
.site-footer{background:var(--c-dark2);border-top:2px solid var(--c-red);padding:48px 0 0}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:32px;max-width:var(--max-w);margin:0 auto;padding:0 20px 40px}
.footer-col h4{color:var(--c-white);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:var(--c-red)}
.footer-col p{font-size:.85rem;color:var(--c-text-muted);line-height:1.7;margin-bottom:8px}
.footer-col a{display:block;color:var(--c-text-muted);font-size:.85rem;padding:4px 0;transition:color var(--transition)}
.footer-col a:hover{color:var(--c-red-light)}
.footer-bottom{border-top:1px solid var(--c-border);padding:20px;text-align:center;font-size:.82rem;color:var(--c-text-muted);max-width:var(--max-w);margin:0 auto}
.footer-bottom a{color:var(--c-text-muted);margin:0 8px}
.footer-bottom a:hover{color:var(--c-red-light)}

/* === 内页通用 === */
.page-hero{background:linear-gradient(135deg,var(--c-dark) 0%,var(--c-gray) 100%);padding:60px 0;text-align:center;border-bottom:2px solid var(--c-red)}
.page-hero h1{font-size:2.2rem;color:var(--c-white);margin-bottom:10px}
.page-hero p{color:var(--c-text-muted);font-size:1rem}
.page-content{padding:48px 0}
.page-content h2{font-size:1.5rem;color:var(--c-white);margin:32px 0 16px}
.page-content h3{font-size:1.2rem;color:var(--c-white);margin:24px 0 12px}
.page-content p{margin-bottom:16px;line-height:1.8}

/* === 统计数字 === */
.stats-row{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;text-align:center;padding:40px 0}
.stat-item .num{font-size:2.4rem;font-weight:700;color:var(--c-red);margin-bottom:6px}
.stat-item .label{font-size:.88rem;color:var(--c-text-muted)}

/* === MCP隐藏 === */
.mcp-section{display:none}

/* === 响应式 === */
@media(max-width:1024px){
  .video-grid{grid-template-columns:repeat(2,1fr)}
  .expert-grid{grid-template-columns:repeat(2,1fr)}
  .footer-grid{grid-template-columns:1fr 1fr}
  .ai-block{grid-template-columns:1fr}
  .howto-steps{grid-template-columns:repeat(2,1fr)}
  .stats-row{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:768px){
  .nav-links{display:none;position:absolute;top:68px;left:0;right:0;background:var(--c-dark);flex-direction:column;padding:16px;border-bottom:2px solid var(--c-red)}
  .nav-links.show{display:flex}
  .nav-toggle{display:flex}
  .hero-section{height:400px}
  .hero-content h1{font-size:1.8rem}
  .video-grid{grid-template-columns:1fr}
  .expert-grid{grid-template-columns:1fr}
  .review-grid{grid-template-columns:1fr}
  .community-features{grid-template-columns:1fr}
  .contact-grid{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr}
  .section{padding:40px 0}
  .section-title h2{font-size:1.5rem}
  .howto-steps{grid-template-columns:1fr}
  .stats-row{grid-template-columns:1fr 1fr}
}
@media(max-width:480px){
  .hero-section{height:320px}
  .hero-content h1{font-size:1.4rem}
  .hero-btns{flex-direction:column;align-items:center}
  .search-wrap{flex-direction:column}
  .search-wrap input{border-right:2px solid var(--c-border);border-radius:var(--radius)}
  .search-wrap button{border-radius:var(--radius)}
  .qr-codes{flex-direction:column;align-items:center}
}