/* ============================================
   91 修车改装视频社区 - 原创样式表
   配色：深海蓝黑 + 赛车红 + 金属金
   ============================================ */

/* === CSS Variables === */
:root {
  --primary-dark: #0F0F1A;
  --secondary-dark: #1A1A2E;
  --accent-red: #E94560;
  --accent-gold: #FFD700;
  --accent-gold-dark: #B8960C;
  --text-light: #E8E8E8;
  --text-muted: #9A9AB0;
  --text-white: #FFFFFF;
  --gradient-start: #16213E;
  --gradient-end: #1A1A2E;
  --card-bg: #1E1E34;
  --card-border: #2A2A45;
  --hover-glow: rgba(233, 69, 96, 0.3);
  --gold-glow: rgba(255, 215, 0, 0.2);
  --shadow-dark: rgba(0, 0, 0, 0.5);
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --transition: all 0.3s ease;
}

/* === Reset & Base === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', Arial, sans-serif;
  background-color: var(--primary-dark);
  color: var(--text-light);
  line-height: 1.7;
  overflow-x: hidden;
}
a { color: var(--accent-gold); text-decoration: none; transition: var(--transition); }
a:hover { color: var(--accent-red); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }
h1, h2, h3, h4, h5, h6 { line-height: 1.3; font-weight: 700; }

/* === Container === */
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.container-wide { max-width: 1400px; margin: 0 auto; padding: 0 20px; }

/* === Header / Navigation === */
.site-header {
  position: fixed; top: 0; left: 0; width: 100%; z-index: 1000;
  background: linear-gradient(180deg, rgba(15,15,26,0.98) 0%, rgba(15,15,26,0.92) 100%);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--card-border);
  transition: var(--transition);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 20px; max-width: 1400px; margin: 0 auto;
}
.logo-wrap { display: flex; align-items: center; gap: 10px; }
.logo-wrap img { height: 42px; width: auto; }
.logo-wrap .brand-text {
  font-size: 1.6rem; font-weight: 800; color: var(--accent-gold);
  letter-spacing: 2px; text-shadow: 0 0 20px var(--gold-glow);
}
.main-nav { display: flex; align-items: center; gap: 0; }
.main-nav a {
  color: var(--text-light); padding: 8px 16px; font-size: 0.95rem;
  font-weight: 500; position: relative; white-space: nowrap;
}
.main-nav a::after {
  content: ''; position: absolute; bottom: 0; left: 50%; width: 0;
  height: 2px; background: var(--accent-red); transition: var(--transition);
  transform: translateX(-50%);
}
.main-nav a:hover { color: var(--accent-gold); }
.main-nav a:hover::after { width: 70%; }
.main-nav a.active { color: var(--accent-gold); }
.main-nav a.active::after { width: 70%; background: var(--accent-gold); }

/* Mobile menu toggle */
.menu-toggle { display: none; cursor: pointer; padding: 8px; }
.menu-toggle span {
  display: block; width: 24px; height: 2px; background: var(--text-light);
  margin: 5px 0; transition: var(--transition);
}

/* === Search Bar === */
.search-bar-wrap {
  background: var(--secondary-dark); border-bottom: 1px solid var(--card-border);
  padding: 10px 0; margin-top: 66px;
}
.search-bar {
  display: flex; align-items: center; max-width: 600px; margin: 0 auto;
  background: var(--card-bg); border: 1px solid var(--card-border);
  border-radius: 30px; overflow: hidden; transition: var(--transition);
}
.search-bar:focus-within { border-color: var(--accent-gold); box-shadow: 0 0 15px var(--gold-glow); }
.search-bar input {
  flex: 1; background: transparent; border: none; color: var(--text-light);
  padding: 10px 20px; font-size: 0.95rem; outline: none;
}
.search-bar input::placeholder { color: var(--text-muted); }
.search-bar button {
  background: linear-gradient(135deg, var(--accent-red), #C73650);
  color: var(--text-white); border: none; padding: 10px 24px;
  cursor: pointer; font-size: 0.95rem; font-weight: 600;
  transition: var(--transition);
}
.search-bar button:hover { background: linear-gradient(135deg, #C73650, var(--accent-red)); }

/* === Hero Banner === */
.hero-banner {
  position: relative; width: 100%; min-height: 520px;
  background-size: cover; background-position: center; background-repeat: no-repeat;
  display: flex; align-items: center; justify-content: center;
  overflow: hidden;
}
.hero-banner::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, rgba(15,15,26,0.85) 0%, rgba(26,26,46,0.6) 50%, rgba(15,15,26,0.85) 100%);
  z-index: 1;
}
.hero-content {
  position: relative; z-index: 2; text-align: center;
  max-width: 800px; padding: 40px 20px;
}
.hero-content h1 {
  font-size: 2.8rem; color: var(--text-white); margin-bottom: 16px;
  text-shadow: 0 4px 20px var(--shadow-dark);
}
.hero-content h1 .brand-highlight { color: var(--accent-gold); }
.hero-content p {
  font-size: 1.15rem; color: var(--text-muted); margin-bottom: 28px;
  line-height: 1.8;
}
.hero-tags { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; }
.hero-tags span {
  background: rgba(233,69,96,0.15); border: 1px solid rgba(233,69,96,0.3);
  color: var(--accent-red); padding: 6px 16px; border-radius: 20px;
  font-size: 0.85rem; font-weight: 500;
}

/* === Section Common === */
.section { padding: 60px 0; }
.section-alt { background: var(--secondary-dark); }
.section-title {
  text-align: center; margin-bottom: 40px;
}
.section-title h2 {
  font-size: 2rem; color: var(--text-white); margin-bottom: 10px;
  position: relative; display: inline-block;
}
.section-title h2::after {
  content: ''; display: block; width: 60px; height: 3px;
  background: linear-gradient(90deg, var(--accent-red), var(--accent-gold));
  margin: 12px auto 0;
  border-radius: 2px;
}
.section-title p { color: var(--text-muted); font-size: 1rem; margin-top: 8px; }

/* === Video Card Grid === */
.video-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
}
.video-card {
  background: var(--card-bg); border: 1px solid var(--card-border);
  border-radius: var(--radius-md); overflow: hidden;
  transition: var(--transition); cursor: pointer;
}
.video-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 40px var(--hover-glow);
  border-color: var(--accent-red);
}
.video-thumb {
  position: relative; width: 100%; padding-top: 56.25%; overflow: hidden;
}
.video-thumb img {
  position: absolute; top: 0; left: 0; width: 100%; height: 100%;
  object-fit: cover; transition: transform 0.5s ease;
}
.video-card:hover .video-thumb img { transform: scale(1.08); }
.video-play-btn {
  position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%);
  width: 60px; height: 60px; background: rgba(233,69,96,0.85);
  border-radius: 50%; display: flex; align-items: center; justify-content: center;
  opacity: 0; transition: var(--transition); z-index: 2;
}
.video-play-btn::after {
  content: ''; width: 0; height: 0;
  border-left: 18px solid var(--text-white);
  border-top: 11px solid transparent;
  border-bottom: 11px solid transparent;
  margin-left: 4px;
}
.video-card:hover .video-play-btn { opacity: 1; }
.video-duration {
  position: absolute; bottom: 8px; right: 8px;
  background: rgba(0,0,0,0.8); color: var(--text-white);
  padding: 2px 8px; border-radius: 4px; font-size: 0.8rem;
  z-index: 2;
}
.video-info { padding: 16px; }
.video-info h3 {
  font-size: 1rem; color: var(--text-white); margin-bottom: 8px;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical;
  overflow: hidden;
}
.video-meta {
  display: flex; align-items: center; gap: 16px;
  font-size: 0.82rem; color: var(--text-muted);
}
.video-meta span { display: flex; align-items: center; gap: 4px; }
.video-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 10px; }
.video-tags span {
  background: rgba(255,215,0,0.1); color: var(--accent-gold);
  padding: 2px 10px; border-radius: 12px; font-size: 0.75rem;
  border: 1px solid rgba(255,215,0,0.2);
}

/* === Expert Cards === */
.expert-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 24px;
}
.expert-card {
  background: var(--card-bg); border: 1px solid var(--card-border);
  border-radius: var(--radius-md); padding: 28px 20px;
  text-align: center; transition: var(--transition);
}
.expert-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 30px var(--gold-glow);
  border-color: var(--accent-gold);
}
.expert-avatar {
  width: 100px; height: 100px; border-radius: 50%;
  object-fit: cover; margin: 0 auto 16px;
  border: 3px solid var(--accent-gold);
}
.expert-card h4 { color: var(--text-white); font-size: 1.1rem; margin-bottom: 4px; }
.expert-card .role { color: var(--accent-red); font-size: 0.85rem; margin-bottom: 12px; }
.expert-card p { color: var(--text-muted); font-size: 0.88rem; margin-bottom: 16px; }
.expert-actions { display: flex; gap: 10px; justify-content: center; }
.btn-sm {
  padding: 6px 16px; border-radius: 20px; font-size: 0.82rem;
  font-weight: 600; cursor: pointer; transition: var(--transition);
  border: none;
}
.btn-primary {
  background: linear-gradient(135deg, var(--accent-red), #C73650);
  color: var(--text-white);
}
.btn-primary:hover { box-shadow: 0 4px 15px var(--hover-glow); }
.btn-outline {
  background: transparent; border: 1px solid var(--accent-gold);
  color: var(--accent-gold);
}
.btn-outline:hover { background: var(--accent-gold); color: var(--primary-dark); }

/* === FAQ Section === */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: var(--card-bg); border: 1px solid var(--card-border);
  border-radius: var(--radius-md); margin-bottom: 12px;
  overflow: hidden; transition: var(--transition);
}
.faq-item:hover { border-color: var(--accent-gold); }
.faq-question {
  padding: 18px 24px; cursor: pointer; display: flex;
  align-items: center; justify-content: space-between;
  font-weight: 600; color: var(--text-white); font-size: 0.95rem;
}
.faq-question::after {
  content: '+'; font-size: 1.4rem; color: var(--accent-gold);
  transition: var(--transition); flex-shrink: 0; margin-left: 12px;
}
.faq-item.active .faq-question::after { content: '-'; }
.faq-answer {
  max-height: 0; overflow: hidden; transition: max-height 0.4s ease;
  padding: 0 24px;
}
.faq-item.active .faq-answer { max-height: 300px; padding: 0 24px 18px; }
.faq-answer p { color: var(--text-muted); font-size: 0.9rem; line-height: 1.7; }

/* === Reviews / Testimonials === */
.review-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}
.review-card {
  background: var(--card-bg); border: 1px solid var(--card-border);
  border-radius: var(--radius-md); padding: 24px;
  transition: var(--transition);
}
.review-card:hover { border-color: var(--accent-red); }
.review-stars { color: var(--accent-gold); font-size: 0.9rem; margin-bottom: 12px; letter-spacing: 2px; }
.review-text { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 14px; font-style: italic; }
.review-author { display: flex; align-items: center; gap: 10px; }
.review-author-avatar {
  width: 36px; height: 36px; border-radius: 50%;
  background: linear-gradient(135deg, var(--accent-red), var(--accent-gold));
  display: flex; align-items: center; justify-content: center;
  color: var(--text-white); font-weight: 700; font-size: 0.85rem;
}
.review-author-info .name { color: var(--text-white); font-size: 0.88rem; font-weight: 600; }
.review-author-info .date { color: var(--text-muted); font-size: 0.78rem; }

/* === Cooperation / Brand Wall === */
.brand-wall {
  display: flex; flex-wrap: wrap; gap: 20px;
  justify-content: center; align-items: center;
}
.brand-wall-item {
  background: var(--card-bg); border: 1px solid var(--card-border);
  border-radius: var(--radius-sm); padding: 16px 28px;
  color: var(--text-muted); font-weight: 600; font-size: 0.95rem;
  transition: var(--transition);
}
.brand-wall-item:hover { border-color: var(--accent-gold); color: var(--accent-gold); }

/* === Contact Section === */
.contact-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}
.contact-card {
  background: var(--card-bg); border: 1px solid var(--card-border);
  border-radius: var(--radius-md); padding: 28px; text-align: center;
}
.contact-card h4 { color: var(--accent-gold); margin-bottom: 12px; font-size: 1.05rem; }
.contact-card p { color: var(--text-muted); font-size: 0.9rem; line-height: 1.8; }

/* === AI Center Feature === */
.ai-features {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
}
.ai-feature-card {
  background: linear-gradient(145deg, var(--card-bg), var(--secondary-dark));
  border: 1px solid var(--card-border); border-radius: var(--radius-md);
  padding: 32px 24px; text-align: center; transition: var(--transition);
  position: relative; overflow: hidden;
}
.ai-feature-card::before {
  content: ''; position: absolute; top: -50%; left: -50%;
  width: 200%; height: 200%;
  background: radial-gradient(circle, rgba(233,69,96,0.05) 0%, transparent 70%);
  transition: var(--transition);
}
.ai-feature-card:hover { border-color: var(--accent-red); transform: translateY(-4px); }
.ai-feature-card .icon {
  font-size: 2.5rem; margin-bottom: 16px; display: block;
}
.ai-feature-card h4 { color: var(--text-white); font-size: 1.1rem; margin-bottom: 10px; }
.ai-feature-card p { color: var(--text-muted); font-size: 0.88rem; }

/* === Social Share === */
.social-share { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.social-share a {
  display: flex; align-items: center; justify-content: center;
  width: 44px; height: 44px; border-radius: 50%;
  background: var(--card-bg); border: 1px solid var(--card-border);
  color: var(--text-muted); font-size: 1rem; transition: var(--transition);
}
.social-share a:hover {
  background: var(--accent-red); color: var(--text-white);
  border-color: var(--accent-red); transform: translateY(-3px);
}

/* === Footer === */
.site-footer {
  background: linear-gradient(180deg, var(--secondary-dark), var(--primary-dark));
  border-top: 1px solid var(--card-border); padding: 48px 0 24px;
}
.footer-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 32px; margin-bottom: 32px;
}
.footer-col h4 {
  color: var(--accent-gold); font-size: 1rem; margin-bottom: 16px;
  padding-bottom: 8px; border-bottom: 1px solid var(--card-border);
}
.footer-col p, .footer-col a { color: var(--text-muted); font-size: 0.88rem; display: block; margin-bottom: 6px; }
.footer-col a:hover { color: var(--accent-gold); }
.footer-qr { display: flex; gap: 16px; margin-top: 12px; }
.footer-qr img { width: 100px; height: 100px; border-radius: var(--radius-sm); border: 1px solid var(--card-border); }
.footer-bottom {
  text-align: center; padding-top: 24px;
  border-top: 1px solid var(--card-border);
  color: var(--text-muted); font-size: 0.82rem;
}
.footer-bottom .brand-gold { color: var(--accent-gold); font-weight: 700; }

/* === Breadcrumb === */
.breadcrumb {
  padding: 14px 0; font-size: 0.85rem; color: var(--text-muted);
  margin-top: 66px;
}
.breadcrumb a { color: var(--accent-gold); }
.breadcrumb span { margin: 0 6px; }

/* === How-To Guide === */
.howto-steps {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 20px; counter-reset: step;
}
.howto-step {
  background: var(--card-bg); border: 1px solid var(--card-border);
  border-radius: var(--radius-md); padding: 24px;
  position: relative; counter-increment: step;
}
.howto-step::before {
  content: counter(step); position: absolute; top: -12px; left: 20px;
  width: 32px; height: 32px; background: var(--accent-red);
  color: var(--text-white); border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 0.9rem;
}
.howto-step h4 { color: var(--text-white); margin-bottom: 8px; margin-top: 8px; }
.howto-step p { color: var(--text-muted); font-size: 0.88rem; }

/* === Buttons === */
.btn {
  display: inline-block; padding: 12px 32px; border-radius: 30px;
  font-weight: 600; font-size: 0.95rem; cursor: pointer;
  transition: var(--transition); border: none; text-align: center;
}
.btn-red {
  background: linear-gradient(135deg, var(--accent-red), #C73650);
  color: var(--text-white);
}
.btn-red:hover { box-shadow: 0 6px 25px var(--hover-glow); transform: translateY(-2px); color: var(--text-white); }
.btn-gold {
  background: linear-gradient(135deg, var(--accent-gold), var(--accent-gold-dark));
  color: var(--primary-dark);
}
.btn-gold:hover { box-shadow: 0 6px 25px var(--gold-glow); transform: translateY(-2px); color: var(--primary-dark); }

/* === Inner Page Banner === */
.inner-banner {
  position: relative; width: 100%; min-height: 280px;
  background-size: cover; background-position: center;
  display: flex; align-items: center; justify-content: center;
  margin-top: 66px;
}
.inner-banner::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, rgba(15,15,26,0.9) 0%, rgba(26,26,46,0.7) 100%);
}
.inner-banner-content { position: relative; z-index: 2; text-align: center; padding: 40px 20px; }
.inner-banner-content h1 { font-size: 2.2rem; color: var(--text-white); margin-bottom: 10px; }
.inner-banner-content p { color: var(--text-muted); font-size: 1rem; }

/* === Community Cards === */
.community-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
}
.community-card {
  background: var(--card-bg); border: 1px solid var(--card-border);
  border-radius: var(--radius-md); overflow: hidden; transition: var(--transition);
}
.community-card:hover { border-color: var(--accent-red); transform: translateY(-4px); }
.community-card-body { padding: 20px; }
.community-card-body h4 { color: var(--text-white); margin-bottom: 8px; }
.community-card-body p { color: var(--text-muted); font-size: 0.9rem; }

/* === Stats Bar === */
.stats-bar {
  display: flex; justify-content: center; flex-wrap: wrap; gap: 40px;
  padding: 40px 0;
}
.stat-item { text-align: center; }
.stat-item .num {
  font-size: 2.4rem; font-weight: 800; color: var(--accent-gold);
  display: block;
}
.stat-item .label { color: var(--text-muted); font-size: 0.9rem; margin-top: 4px; }

/* === MCP Service Frontend (Decorative) === */
.mcp-service {
  background: var(--card-bg); border: 1px solid var(--card-border);
  border-radius: var(--radius-md); padding: 20px; margin-top: 20px;
}
.mcp-terminal {
  background: #0a0a14; border-radius: var(--radius-sm); padding: 16px;
  font-family: 'Courier New', monospace; font-size: 0.82rem;
  color: #00ff88; line-height: 1.6; max-height: 200px; overflow-y: auto;
}
.mcp-terminal .prompt { color: var(--accent-gold); }
.mcp-terminal .cmd { color: #00ff88; }
.mcp-terminal .output { color: var(--text-muted); }

/* === Image Placeholder === */

/* === Responsive === */
@media (max-width: 768px) {
  .hero-content h1 { font-size: 1.8rem; }
  .hero-banner { min-height: 400px; }
  .section { padding: 40px 0; }
  .section-title h2 { font-size: 1.5rem; }
  .video-grid { grid-template-columns: 1fr; }
  .expert-grid { grid-template-columns: repeat(2, 1fr); }
  .main-nav { 
    display: none; position: fixed; top: 66px; left: 0; width: 100%;
    background: var(--primary-dark); flex-direction: column;
    padding: 20px; border-bottom: 1px solid var(--card-border);
  }
  .main-nav.active { display: flex; }
  .main-nav a { padding: 12px 0; border-bottom: 1px solid var(--card-border); }
  .menu-toggle { display: block; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .stats-bar { gap: 20px; }
  .stat-item .num { font-size: 1.8rem; }
  .header-inner { padding: 10px 16px; }
  .search-bar-wrap { margin-top: 58px; }
  .breadcrumb { margin-top: 58px; }
  .inner-banner { margin-top: 58px; min-height: 200px; }
}

@media (max-width: 480px) {
  .hero-content h1 { font-size: 1.4rem; }
  .expert-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .review-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .ai-features { grid-template-columns: 1fr; }
}

/* === Scrollbar === */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--primary-dark); }
::-webkit-scrollbar-thumb { background: var(--card-border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--accent-red); }

/* === Animation === */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}
.animate-in { animation: fadeInUp 0.6s ease forwards; }

/* === Category Tabs === */
.cat-tabs { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; margin-bottom: 30px; }
.cat-tab {
  padding: 8px 20px; border-radius: 20px; font-size: 0.88rem;
  background: var(--card-bg); border: 1px solid var(--card-border);
  color: var(--text-muted); cursor: pointer; transition: var(--transition);
}
.cat-tab:hover, .cat-tab.active {
  background: var(--accent-red); color: var(--text-white);
  border-color: var(--accent-red);
}