/* 原创样式 - 视频社区 */
/* 配色方案: 深碳灰 #1a1a2e / 赛车红 #c41e3a / 钛金灰 #2d2d44 / 亮银 #e8e8f0 */

:root {
  --brand-dark: #1a1a2e;
  --brand-red: #c41e3a;
  --brand-gray: #2d2d44;
  --brand-silver: #e8e8f0;
  --brand-gold: #d4a853;
  --text-primary: #f0f0f5;
  --text-secondary: #b0b0c0;
  --card-bg: #22223a;
  --border-color: #3a3a55;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  background: var(--brand-dark);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--brand-red); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--brand-gold); }
ul { list-style: none; }

.main-nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(26,26,46,0.95); backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
}
.nav-inner {
  max-width: 1400px; margin: 0 auto; padding: 0 24px;
  display: flex; align-items: center; justify-content: space-between; height: 64px;
}
.nav-logo { display: flex; align-items: center; gap: 10px; }
.nav-logo img { border-radius: 8px; }
.nav-brand { font-size: 1.3rem; font-weight: 700; color: var(--text-primary); }
.nav-links { display: flex; gap: 4px; }
.nav-links li a {
  padding: 8px 14px; border-radius: 6px; font-size: 0.9rem;
  color: var(--text-secondary); transition: all 0.2s;
}
.nav-links li a:hover { color: var(--text-primary); background: var(--brand-gray); }
.nav-toggle { display: none; background: none; border: none; color: var(--text-primary); font-size: 1.5rem; cursor: pointer; }

.hero-section { position: relative; min-height: 85vh; display: flex; align-items: center; margin-top: 64px; overflow: hidden; }
.hero-bg {
  position: absolute; inset: 0; background-size: cover; background-position: center;
  filter: brightness(0.4);
}
.hero-overlay {
  position: relative; z-index: 2; max-width: 800px; padding: 60px 40px; margin-left: 8%;
}
.hero-overlay h1 { font-size: 2.8rem; font-weight: 800; margin-bottom: 16px; line-height: 1.2; }
.hero-overlay h2 { font-size: 1.3rem; font-weight: 400; color: var(--text-secondary); margin-bottom: 20px; }
.hero-desc { font-size: 1rem; color: var(--text-secondary); margin-bottom: 32px; line-height: 1.8; }
.hero-btns { display: flex; gap: 16px; flex-wrap: wrap; }
.btn-primary {
  display: inline-block; padding: 14px 32px; background: var(--brand-red);
  color: #fff; border-radius: 8px; font-weight: 600; transition: transform 0.15s, background 0.2s;
}
.btn-primary:hover { background: #a01830; transform: scale(0.97); color: #fff; }
.btn-secondary {
  display: inline-block; padding: 14px 32px; border: 2px solid var(--brand-red);
  color: var(--brand-red); border-radius: 8px; font-weight: 600; transition: all 0.2s;
}
.btn-secondary:hover { background: var(--brand-red); color: #fff; }

.page-main { max-width: 1400px; margin: 0 auto; padding: 60px 24px; }

.section-header { text-align: center; margin-bottom: 48px; }
.section-header h2 { font-size: 2rem; font-weight: 700; margin-bottom: 12px; }
.section-header p { color: var(--text-secondary); font-size: 1.05rem; max-width: 700px; margin: 0 auto; }
.section-more { text-align: center; margin-top: 36px; }
.section-more a { font-size: 1.1rem; font-weight: 600; }

.video-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 24px; }
.video-card {
  background: var(--card-bg); border-radius: 12px; overflow: hidden;
  border: 1px solid var(--border-color); transition: transform 0.2s, box-shadow 0.2s;
}
.video-card:hover { transform: translateY(-4px); box-shadow: 0 12px 40px rgba(196,30,58,0.15); }
.video-thumb { position: relative; aspect-ratio: 16/9; overflow: hidden; }
.video-thumb img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.3s; }
.video-card:hover .video-thumb img { transform: scale(1.05); }
.video-play-btn {
  position: absolute; top: 50%; left: 50%; transform: translate(-50%,-50%);
  opacity: 0; transition: opacity 0.25s; cursor: pointer;
}
.video-card:hover .video-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: 0.8rem;
}
.video-info { padding: 16px; }
.video-info h3 { font-size: 1rem; font-weight: 600; margin-bottom: 8px; color: var(--text-primary); }
.video-info p { font-size: 0.85rem; color: var(--text-secondary); }

.media-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 24px; }
.media-item {
  background: var(--card-bg); border-radius: 12px; overflow: hidden;
  border: 1px solid var(--border-color);
}
.media-item img { width: 100%; height: 200px; object-fit: cover; }
.media-item h3 { padding: 16px 16px 8px; font-size: 1.1rem; }
.media-item p { padding: 0 16px 16px; font-size: 0.9rem; color: var(--text-secondary); }

.ent-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 20px; }
.ent-card {
  background: linear-gradient(135deg, var(--card-bg), var(--brand-gray));
  padding: 28px; border-radius: 12px; border: 1px solid var(--border-color);
}
.ent-card h3 { font-size: 1.1rem; margin-bottom: 10px; color: var(--brand-gold); }
.ent-card p { font-size: 0.9rem; color: var(--text-secondary); }

.section-ai { margin: 80px 0; }
.section-inner-split { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; }
.section-inner-split.reverse { direction: rtl; }
.section-inner-split.reverse > * { direction: ltr; }
.ai-text h2 { font-size: 1.8rem; margin-bottom: 16px; }
.ai-text p { color: var(--text-secondary); margin-bottom: 16px; }
.ai-text ul { padding-left: 0; }
.ai-text li { padding: 8px 0; color: var(--text-secondary); }
.ai-text li strong { color: var(--text-primary); }
.ai-img img { border-radius: 12px; }

.community-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 20px; }
.community-item {
  background: var(--card-bg); padding: 24px; border-radius: 12px;
  border-left: 4px solid var(--brand-red);
}
.community-item h3 { margin-bottom: 8px; font-size: 1.05rem; }
.community-item p { font-size: 0.85rem; color: var(--text-secondary); }

.expert-text h2 { font-size: 1.8rem; margin-bottom: 16px; }
.expert-text p { color: var(--text-secondary); margin-bottom: 16px; }
.expert-text li { padding: 6px 0; color: var(--text-secondary); }
.expert-text li strong { color: var(--text-primary); }
.expert-img img { border-radius: 12px; }

.section-faq { margin-top: 80px; }
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item { background: var(--card-bg); padding: 24px; border-radius: 10px; margin-bottom: 16px; border: 1px solid var(--border-color); }
.faq-item h3 { font-size: 1.05rem; margin-bottom: 10px; color: var(--brand-gold); }
.faq-item p { font-size: 0.9rem; color: var(--text-secondary); line-height: 1.8; }

.breadcrumb { max-width: 1400px; margin: 80px auto 0; padding: 16px 24px; font-size: 0.85rem; color: var(--text-secondary); }
.breadcrumb a { color: var(--text-secondary); }
.breadcrumb a:hover { color: var(--brand-red); }

.page-hero-sm {
  position: relative; height: 300px; display: flex; flex-direction: column;
  justify-content: center; align-items: center; text-align: center;
  background-size: cover; background-position: center; border-radius: 16px;
  margin-bottom: 48px; overflow: hidden;
}
.page-hero-sm::before {
  content: ''; position: absolute; inset: 0; background: rgba(26,26,46,0.7);
}
.page-hero-sm h1, .page-hero-sm h2 { position: relative; z-index: 2; }
.page-hero-sm h1 { font-size: 2.2rem; margin-bottom: 10px; }
.page-hero-sm h2 { font-size: 1.1rem; color: var(--text-secondary); font-weight: 400; }

.community-stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 20px; margin: 40px 0; }
.stat-item { text-align: center; padding: 24px; background: var(--card-bg); border-radius: 12px; }
.stat-num { display: block; font-size: 1.8rem; font-weight: 800; color: var(--brand-red); }
.stat-label { font-size: 0.9rem; color: var(--text-secondary); }

.topic-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 20px; }
.topic-card { background: var(--card-bg); padding: 24px; border-radius: 12px; border: 1px solid var(--border-color); }
.topic-card h3 { margin-bottom: 8px; color: var(--brand-gold); }
.topic-card p { font-size: 0.9rem; color: var(--text-secondary); margin-bottom: 8px; }
.topic-count { font-size: 0.8rem; color: var(--brand-red); }

.experts-list { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 24px; }
.expert-card { background: var(--card-bg); border-radius: 12px; overflow: hidden; border: 1px solid var(--border-color); }
.expert-card img { width: 100%; height: 200px; object-fit: cover; }
.expert-card h3 { padding: 16px 16px 4px; font-size: 1.1rem; }
.expert-card .expert-title { padding: 0 16px; font-size: 0.85rem; color: var(--brand-red); margin-bottom: 8px; }
.expert-card p { padding: 0 16px; font-size: 0.85rem; color: var(--text-secondary); }
.expert-card .expert-certs { padding: 12px 16px 16px; }
.expert-card .expert-certs li { font-size: 0.8rem; color: var(--text-secondary); padding: 2px 0; }

.tools-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 24px; }
.tool-card {
  background: var(--card-bg); padding: 28px; border-radius: 12px;
  border: 1px solid var(--border-color); transition: border-color 0.2s;
}
.tool-card:hover { border-color: var(--brand-red); }
.tool-card h3 { font-size: 1.1rem; margin-bottom: 12px; color: var(--brand-gold); }
.tool-card p { font-size: 0.9rem; color: var(--text-secondary); }

.cat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; }
.cat-item { background: var(--card-bg); padding: 20px; border-radius: 10px; text-align: center; border: 1px solid var(--border-color); transition: border-color 0.2s; }
.cat-item:hover { border-color: var(--brand-red); }
.cat-item h3 { font-size: 0.95rem; color: var(--text-primary); }

.about-content { max-width: 900px; }
.about-content h2 { font-size: 1.8rem; margin-bottom: 16px; }
.about-content h3 { font-size: 1.3rem; margin: 32px 0 12px; color: var(--brand-gold); }
.about-content p { color: var(--text-secondary); margin-bottom: 16px; line-height: 1.8; }
.about-content li { padding: 6px 0; color: var(--text-secondary); }

.suv-intro, .experts-intro, .tools-intro, .community-intro { margin-bottom: 48px; }
.suv-intro h2, .experts-intro h2, .tools-intro h2, .community-intro h2 { font-size: 1.8rem; margin-bottom: 16px; }
.suv-intro p, .experts-intro p, .tools-intro p, .community-intro p { color: var(--text-secondary); line-height: 1.8; max-width: 900px; }
.suv-videos h2, .video-categories h2, .community-topics h2 { font-size: 1.5rem; margin-bottom: 24px; }

.site-footer { background: var(--brand-gray); margin-top: 80px; border-top: 1px solid var(--border-color); }
.footer-inner { max-width: 1400px; margin: 0 auto; padding: 48px 24px; display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px; }
.footer-brand img { margin-bottom: 12px; border-radius: 8px; }
.footer-brand p { color: var(--text-secondary); font-size: 0.9rem; margin-top: 4px; }
.footer-links h4, .footer-contact h4 { margin-bottom: 16px; font-size: 1rem; }
.footer-links li { margin-bottom: 8px; }
.footer-links a { color: var(--text-secondary); font-size: 0.9rem; }
.footer-links a:hover { color: var(--brand-red); }
.footer-contact p { color: var(--text-secondary); font-size: 0.9rem; margin-bottom: 6px; }
.footer-bottom { text-align: center; padding: 20px; border-top: 1px solid var(--border-color); }
.footer-bottom p { color: var(--text-secondary); font-size: 0.8rem; margin: 4px 0; }

@media (max-width: 1024px) {
  .section-inner-split { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-toggle { display: block; }
  .nav-links.active { display: flex; flex-direction: column; position: absolute; top: 64px; left: 0; right: 0; background: var(--brand-dark); padding: 16px; border-bottom: 1px solid var(--border-color); }
  .hero-overlay { margin-left: 0; padding: 40px 20px; }
  .hero-overlay h1 { font-size: 1.8rem; }
  .video-grid { grid-template-columns: 1fr; }
  .page-hero-sm { height: 200px; }
  .page-hero-sm h1 { font-size: 1.5rem; }
}