/* ========================================
   人文自然创意视频社区 - 原创CSS样式
   配色：森林绿 #1B5E20 / 翡翠绿 #2ECC71 / 暖木棕 #5D4037 / 奶白 #FAFDF6
   ======================================== */

* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --primary: #1B5E20;
  --primary-light: #2ECC71;
  --accent: #5D4037;
  --bg-main: #FAFDF6;
  --bg-alt: #E8F5E9;
  --bg-dark: #0D2818;
  --text-main: #1A1A1A;
  --text-light: #555;
  --text-white: #FAFDF6;
  --border: #C8E6C9;
  --shadow: rgba(27,94,32,0.12);
  --radius: 12px;
  --transition: all 0.3s ease;
}

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  background: var(--bg-main);
  color: var(--text-main);
  line-height: 1.7;
  overflow-x: hidden;
}

a { color: var(--primary); text-decoration: none; transition: var(--transition); }
a:hover { color: var(--primary-light); }

img { max-width: 100%; height: auto; display: block; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  background: var(--bg-dark);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 20px var(--shadow);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  max-width: 1200px;
  margin: 0 auto;
}

.logo-area { display: flex; align-items: center; gap: 10px; }
.logo-area img { height: 42px; width: auto; }
.logo-area h1 { font-size: 1.4rem; color: var(--primary-light); margin: 0; font-weight: 700; }

.main-nav { display: flex; gap: 24px; list-style: none; }
.main-nav a { color: var(--text-white); font-size: 0.95rem; padding: 6px 0; position: relative; }
.main-nav a:hover { color: var(--primary-light); }
.main-nav a::after { content: ''; position: absolute; bottom: 0; left: 0; width: 0; height: 2px; background: var(--primary-light); transition: var(--transition); }
.main-nav a:hover::after { width: 100%; }

.menu-toggle { display: none; background: none; border: none; color: var(--text-white); font-size: 1.5rem; cursor: pointer; }

/* Search Bar */
.search-bar {
  background: var(--bg-alt);
  padding: 12px 0;
  border-bottom: 1px solid var(--border);
}

.search-form {
  display: flex;
  max-width: 600px;
  margin: 0 auto;
  gap: 8px;
}

.search-input {
  flex: 1;
  padding: 10px 16px;
  border: 2px solid var(--border);
  border-radius: 25px;
  font-size: 0.9rem;
  outline: none;
  transition: var(--transition);
}

.search-input:focus { border-color: var(--primary-light); box-shadow: 0 0 0 3px rgba(46,204,113,0.15); }

.search-btn {
  padding: 10px 24px;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 25px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: var(--transition);
}

.search-btn:hover { background: var(--primary-light); }

.search-tags { display: flex; gap: 8px; justify-content: center; margin-top: 8px; flex-wrap: wrap; }
.search-tags span {
  padding: 4px 12px;
  background: white;
  border: 1px solid var(--border);
  border-radius: 15px;
  font-size: 0.8rem;
  color: var(--text-light);
  cursor: pointer;
  transition: var(--transition);
}
.search-tags span:hover { background: var(--primary-light); color: white; border-color: var(--primary-light); }

/* Announce Bar */
.announce-bar {
  background: linear-gradient(90deg, var(--primary), var(--primary-light));
  color: white;
  text-align: center;
  padding: 8px 20px;
  font-size: 0.85rem;
  overflow: hidden;
  white-space: nowrap;
}

.announce-bar a { color: #FFD700; font-weight: 600; }

/* Hero Section */
.hero-section {
  position: relative;
  height: 520px;
  overflow: hidden;
  display: flex;
  align-items: center;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  z-index: 1;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(13,40,24,0.85), rgba(27,94,32,0.6));
  z-index: 2;
}

.hero-content {
  position: relative;
  z-index: 3;
  color: white;
  max-width: 700px;
  padding: 0 40px;
}

.hero-content h2 { font-size: 2.6rem; margin-bottom: 16px; line-height: 1.3; text-shadow: 0 2px 10px rgba(0,0,0,0.3); }
.hero-content p { font-size: 1.1rem; margin-bottom: 24px; opacity: 0.9; line-height: 1.8; }

.hero-btns { display: flex; gap: 16px; flex-wrap: wrap; }
.btn-primary {
  padding: 12px 32px;
  background: var(--primary-light);
  color: white;
  border-radius: 30px;
  font-weight: 600;
  font-size: 1rem;
  transition: var(--transition);
  display: inline-block;
}
.btn-primary:hover { background: #27AE60; transform: translateY(-2px); box-shadow: 0 6px 20px rgba(46,204,113,0.4); color: white; }

.btn-outline {
  padding: 12px 32px;
  border: 2px solid white;
  color: white;
  border-radius: 30px;
  font-weight: 600;
  font-size: 1rem;
  transition: var(--transition);
  display: inline-block;
}
.btn-outline:hover { background: white; color: var(--primary); }

/* Stats Bar */
.stats-bar {
  background: var(--bg-dark);
  padding: 20px 0;
  border-bottom: 3px solid var(--primary-light);
}

.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; text-align: center; }
.stat-item h3 { font-size: 2rem; color: var(--primary-light); margin-bottom: 4px; }
.stat-item p { color: var(--text-white); font-size: 0.85rem; opacity: 0.8; }

/* Section Common */
.section { padding: 60px 0; }
.section-alt { background: var(--bg-alt); }
.section-dark { background: var(--bg-dark); color: var(--text-white); }

.section-title {
  text-align: center;
  margin-bottom: 40px;
}
.section-title h2 { font-size: 2rem; color: var(--primary); margin-bottom: 8px; }
.section-title p { color: var(--text-light); font-size: 1rem; }

/* Video Cards */
.video-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }

.video-card {
  background: white;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 4px 15px var(--shadow);
  transition: var(--transition);
  position: relative;
}

.video-card:hover { transform: translateY(-6px); box-shadow: 0 12px 30px var(--shadow); }

.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: var(--transition);
}

.video-card:hover .video-thumb img { transform: scale(1.05); }

.play-btn {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%) scale(0);
  width: 60px;
  height: 60px;
  background: rgba(46,204,113,0.9);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.play-btn::after {
  content: '';
  border-style: solid;
  border-width: 10px 0 10px 18px;
  border-color: transparent transparent transparent white;
  margin-left: 4px;
}

.video-card:hover .play-btn { transform: translate(-50%, -50%) scale(1); }

.video-badge {
  position: absolute;
  top: 10px;
  left: 10px;
  background: var(--primary-light);
  color: white;
  padding: 3px 10px;
  border-radius: 4px;
  font-size: 0.75rem;
  font-weight: 600;
}

.video-duration {
  position: absolute;
  bottom: 10px;
  right: 10px;
  background: rgba(0,0,0,0.75);
  color: white;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.75rem;
}

.video-info { padding: 16px; }
.video-info h3 { font-size: 0.95rem; margin-bottom: 8px; line-height: 1.4; color: var(--text-main); }
.video-meta { display: flex; gap: 12px; font-size: 0.8rem; color: var(--text-light); }

/* Category Tabs */
.cat-tabs { display: flex; gap: 12px; justify-content: center; margin-bottom: 30px; flex-wrap: wrap; }
.cat-tab {
  padding: 8px 20px;
  background: white;
  border: 2px solid var(--border);
  border-radius: 25px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: var(--transition);
}
.cat-tab:hover, .cat-tab.active { background: var(--primary); color: white; border-color: var(--primary); }

/* AI Section */
.ai-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.ai-card {
  background: white;
  border-radius: var(--radius);
  padding: 30px;
  text-align: center;
  box-shadow: 0 4px 15px var(--shadow);
  transition: var(--transition);
}
.ai-card:hover { transform: translateY(-4px); }
.ai-icon { font-size: 3rem; margin-bottom: 16px; }
.ai-card h3 { color: var(--primary); margin-bottom: 10px; font-size: 1.1rem; }
.ai-card p { color: var(--text-light); font-size: 0.9rem; line-height: 1.6; }

/* Expert Section */
.expert-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.expert-card {
  background: white;
  border-radius: var(--radius);
  padding: 24px;
  display: flex;
  gap: 20px;
  box-shadow: 0 4px 15px var(--shadow);
  transition: var(--transition);
}
.expert-card:hover { transform: translateY(-3px); }
.expert-avatar { width: 100px; height: 100px; border-radius: 50%; object-fit: cover; border: 3px solid var(--primary-light); flex-shrink: 0; }
.expert-info h3 { color: var(--primary); margin-bottom: 4px; }
.expert-info .role { color: var(--text-light); font-size: 0.85rem; margin-bottom: 8px; }
.expert-info p { font-size: 0.9rem; color: var(--text-light); line-height: 1.5; }
.expert-btns { display: flex; gap: 8px; margin-top: 10px; }
.expert-btns a {
  padding: 5px 14px;
  border: 1px solid var(--primary);
  border-radius: 20px;
  font-size: 0.8rem;
  color: var(--primary);
}
.expert-btns a:hover { background: var(--primary); color: white; }

/* Brand Wall */
.brand-wall { display: flex; flex-wrap: wrap; justify-content: center; gap: 30px; align-items: center; padding: 20px 0; }
.brand-item {
  padding: 15px 25px;
  background: white;
  border-radius: 8px;
  box-shadow: 0 2px 8px var(--shadow);
  font-weight: 600;
  color: var(--accent);
  transition: var(--transition);
}
.brand-item:hover { transform: scale(1.05); box-shadow: 0 4px 15px var(--shadow); }

/* FAQ */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: white;
  border-radius: var(--radius);
  margin-bottom: 12px;
  box-shadow: 0 2px 8px var(--shadow);
  overflow: hidden;
}
.faq-q {
  padding: 18px 24px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: var(--transition);
}
.faq-q:hover { background: var(--bg-alt); }
.faq-q::after { content: '+'; font-size: 1.4rem; color: var(--primary); transition: var(--transition); }
.faq-item.active .faq-q::after { content: '-'; }
.faq-a { padding: 0 24px 18px; color: var(--text-light); line-height: 1.7; display: none; }
.faq-item.active .faq-a { display: block; }

/* Reviews */
.review-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.review-card {
  background: white;
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: 0 4px 15px var(--shadow);
}
.review-header { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; }
.review-avatar { width: 48px; height: 48px; border-radius: 50%; background: var(--primary-light); display: flex; align-items: center; justify-content: center; color: white; font-weight: 700; font-size: 1.2rem; }
.review-name { font-weight: 600; }
.review-stars { color: #FFD700; font-size: 0.9rem; }
.review-text { color: var(--text-light); font-size: 0.9rem; line-height: 1.6; font-style: italic; }

/* Contact */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: start; }
.contact-info h3 { color: var(--primary); margin-bottom: 16px; font-size: 1.2rem; }
.contact-item { display: flex; gap: 12px; margin-bottom: 14px; align-items: center; }
.contact-item .icon { width: 36px; height: 36px; background: var(--bg-alt); border-radius: 50%; display: flex; align-items: center; justify-content: center; color: var(--primary); font-weight: 700; flex-shrink: 0; }
.contact-qr { display: flex; gap: 20px; }
.contact-qr img { width: 120px; height: 120px; border: 2px solid var(--border); border-radius: 8px; }

/* Share */
.share-section { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; padding: 20px 0; }
.share-btn {
  padding: 10px 20px;
  border-radius: 25px;
  color: white;
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  border: none;
}
.share-btn:hover { transform: translateY(-2px); opacity: 0.9; }
.share-btn.wechat { background: #07C160; }
.share-btn.weibo { background: #E6162D; }
.share-btn.douyin { background: #161823; }
.share-btn.bilibili { background: #00A1D6; }

/* Footer */
.site-footer {
  background: var(--bg-dark);
  color: var(--text-white);
  padding: 50px 0 20px;
}

.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; margin-bottom: 30px; }
.footer-brand h3 { color: var(--primary-light); font-size: 1.3rem; margin-bottom: 12px; }
.footer-brand p { color: #AAA; font-size: 0.9rem; line-height: 1.6; }
.footer-col h4 { color: var(--primary-light); margin-bottom: 14px; font-size: 1rem; }
.footer-col a { display: block; color: #AAA; font-size: 0.85rem; margin-bottom: 8px; }
.footer-col a:hover { color: var(--primary-light); }

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 20px;
  text-align: center;
  color: #888;
  font-size: 0.8rem;
}

/* Back to Top */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 45px;
  height: 45px;
  background: var(--primary);
  color: white;
  border-radius: 50%;
  display: none;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  cursor: pointer;
  z-index: 999;
  transition: var(--transition);
  border: none;
}
.back-to-top:hover { background: var(--primary-light); transform: translateY(-3px); }

/* Mobile Nav */
.mobile-nav {
  display: none;
  position: fixed;
  top: 0;
  right: -280px;
  width: 280px;
  height: 100vh;
  background: var(--bg-dark);
  z-index: 2000;
  padding: 60px 20px 20px;
  transition: right 0.3s ease;
  overflow-y: auto;
}
.mobile-nav.active { right: 0; }
.mobile-nav a { display: block; color: var(--text-white); padding: 14px 0; border-bottom: 1px solid rgba(255,255,255,0.1); font-size: 1rem; }
.close-btn { position: absolute; top: 15px; right: 15px; background: none; border: none; color: white; font-size: 1.8rem; cursor: pointer; }

/* Breadcrumb */
.breadcrumb {
  padding: 14px 0;
  font-size: 0.85rem;
  color: var(--text-light);
  border-bottom: 1px solid var(--border);
}
.breadcrumb a { color: var(--primary); }
.breadcrumb span { margin: 0 6px; }

/* Responsive */
@media (max-width: 992px) {
  .video-grid { grid-template-columns: repeat(2, 1fr); }
  .ai-grid { grid-template-columns: repeat(2, 1fr); }
  .expert-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .main-nav { display: none; }
  .menu-toggle { display: block; }
  .mobile-nav { display: block; }
  .hero-section { height: 400px; }
  .hero-content h2 { font-size: 1.8rem; }
  .video-grid { grid-template-columns: 1fr; }
  .ai-grid { grid-template-columns: 1fr; }
  .review-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
  .stat-item h3 { font-size: 1.4rem; }
  .section { padding: 40px 0; }
  .hero-content { padding: 0 20px; }
}

@media (max-width: 480px) {
  .hero-btns { flex-direction: column; }
  .search-form { flex-direction: column; }
  .cat-tabs { gap: 6px; }
  .cat-tab { padding: 6px 14px; font-size: 0.8rem; }
}