/* ===== 51糖心 主样式 ===== */
/* 51tangxin.cn */

/* ===== CSS变量 ===== */
:root {
  --primary: #E91E8C;
  --primary-dark: #C2185B;
  --primary-light: #F06292;
  --secondary: #7B2FBE;
  --accent: #FF6B35;
  --gradient: linear-gradient(135deg, #E91E8C 0%, #7B2FBE 100%);
  --gradient-warm: linear-gradient(135deg, #FF6B35 0%, #E91E8C 100%);
  --bg: #0D0D1A;
  --bg-card: #141428;
  --bg-card2: #1A1A35;
  --border: rgba(255,255,255,0.08);
  --text: #F0F0F8;
  --text-muted: #8888AA;
  --text-dim: #5A5A7A;
  --shadow: 0 8px 32px rgba(0,0,0,0.4);
  --shadow-card: 0 4px 20px rgba(0,0,0,0.3);
  --radius: 12px;
  --radius-lg: 20px;
  --radius-sm: 8px;
  --transition: 0.25s ease;
}

/* ===== 重置 ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--primary-light); }
img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }
button { cursor: pointer; border: none; outline: none; }
h1,h2,h3,h4,h5,h6 { line-height: 1.3; }

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

/* ===== 头部 ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(13,13,26,0.95);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.logo-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
.logo-img {
  height: 40px;
  width: auto;
  border-radius: 8px;
}
.logo-text {
  font-size: 1.3rem;
  font-weight: 900;
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.5px;
}
.main-nav {
  display: flex;
  align-items: center;
  gap: 4px;
}
.main-nav a {
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: all var(--transition);
  white-space: nowrap;
}
.main-nav a:hover,
.main-nav a.active {
  color: var(--text);
  background: rgba(255,255,255,0.06);
}
.main-nav a.nav-btn {
  background: var(--gradient);
  color: #fff;
  padding: 8px 18px;
  border-radius: 20px;
  font-weight: 600;
}
.main-nav a.nav-btn:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  border-radius: var(--radius-sm);
  transition: background var(--transition);
}
.hamburger:hover { background: rgba(255,255,255,0.06); }
.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: all var(--transition);
}
.hamburger.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* ===== 搜索栏 ===== */
.search-bar-wrap {
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  padding: 12px 0;
}
.search-bar-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}
.search-form {
  display: flex;
  flex: 1;
  min-width: 260px;
  max-width: 480px;
  background: var(--bg-card2);
  border: 1px solid var(--border);
  border-radius: 24px;
  overflow: hidden;
}
.search-input {
  flex: 1;
  background: none;
  border: none;
  padding: 10px 16px;
  color: var(--text);
  font-size: 0.9rem;
  outline: none;
}
.search-input::placeholder { color: var(--text-dim); }
.search-btn {
  background: var(--gradient);
  color: #fff;
  border: none;
  padding: 10px 20px;
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: opacity var(--transition);
}
.search-btn:hover { opacity: 0.9; }
.search-tags {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.search-tag {
  background: rgba(233,30,140,0.1);
  border: 1px solid rgba(233,30,140,0.25);
  color: var(--primary-light);
  padding: 5px 12px;
  border-radius: 14px;
  font-size: 0.8rem;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}
.search-tag:hover {
  background: rgba(233,30,140,0.2);
  border-color: var(--primary);
}

/* ===== Hero 首屏 ===== */
.hero-section {
  position: relative;
  min-height: 560px;
  display: flex;
  align-items: center;
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background: url('/assets/images/hero-bg.jpg') center/cover no-repeat;
  z-index: 0;
}
.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(13,13,26,0.92) 0%, rgba(123,47,190,0.6) 100%);
  z-index: 1;
}
.hero-content {
  position: relative;
  z-index: 2;
  max-width: 1200px;
  margin: 0 auto;
  padding: 60px 20px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
  width: 100%;
}
.hero-text h1 {
  font-size: clamp(2rem, 4vw, 3.2rem);
  font-weight: 900;
  line-height: 1.2;
  margin-bottom: 16px;
  color: #fff;
}
.hero-text h1 span {
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-text p {
  font-size: 1rem;
  color: rgba(255,255,255,0.75);
  margin-bottom: 28px;
  line-height: 1.8;
}
.hero-btns {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 32px;
}
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--gradient);
  color: #fff;
  padding: 12px 28px;
  border-radius: 24px;
  font-size: 0.95rem;
  font-weight: 700;
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  box-shadow: 0 4px 20px rgba(233,30,140,0.4);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(233,30,140,0.5);
  color: #fff;
}
.btn-outline {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: transparent;
  color: #fff;
  padding: 12px 28px;
  border-radius: 24px;
  font-size: 0.95rem;
  font-weight: 600;
  border: 1.5px solid rgba(255,255,255,0.4);
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
}
.btn-outline:hover {
  background: rgba(255,255,255,0.08);
  border-color: rgba(255,255,255,0.7);
  color: #fff;
}
.hero-stats {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}
.stat-item { text-align: center; }
.stat-num {
  font-size: 1.8rem;
  font-weight: 900;
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
}
.stat-label {
  font-size: 0.75rem;
  color: rgba(255,255,255,0.6);
  margin-top: 4px;
}
.hero-video-preview {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
}
.hero-video-preview img {
  width: 100%;
  height: 320px;
  object-fit: cover;
}
.hero-play-btn {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.3);
  cursor: pointer;
  transition: background var(--transition);
}
.hero-play-btn:hover { background: rgba(0,0,0,0.5); }
.play-circle {
  width: 72px;
  height: 72px;
  background: var(--gradient);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  color: #fff;
  box-shadow: 0 4px 24px rgba(233,30,140,0.5);
  transition: transform var(--transition);
  padding-left: 4px;
}
.hero-play-btn:hover .play-circle { transform: scale(1.1); }

/* ===== 通用Section ===== */
.section {
  padding: 64px 0;
}
.section-alt {
  background: var(--bg-card);
}
.section-header {
  text-align: center;
  margin-bottom: 40px;
}
.section-tag {
  display: inline-block;
  background: rgba(233,30,140,0.12);
  border: 1px solid rgba(233,30,140,0.3);
  color: var(--primary-light);
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 0.82rem;
  font-weight: 600;
  margin-bottom: 12px;
  letter-spacing: 0.5px;
}
.section-title {
  font-size: clamp(1.5rem, 3vw, 2.2rem);
  font-weight: 900;
  margin-bottom: 12px;
  color: var(--text);
}
.section-title span {
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.section-desc {
  font-size: 0.95rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto;
  line-height: 1.7;
}

/* ===== 分类标签 ===== */
.category-tabs {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  padding: 0 20px;
  max-width: 1200px;
  margin: 0 auto;
}
.cat-tab {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 8px 18px;
  border-radius: 20px;
  font-size: 0.88rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}
.cat-tab:hover,
.cat-tab.active {
  background: var(--gradient);
  border-color: transparent;
  color: #fff;
  font-weight: 600;
}

/* ===== 视频网格 ===== */
.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}
.video-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  cursor: pointer;
  transition: all var(--transition);
  position: relative;
}
.video-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card);
  border-color: rgba(233,30,140,0.3);
}
.video-thumb {
  position: relative;
  aspect-ratio: 16/9;
  overflow: hidden;
  background: var(--bg-card2);
}
.video-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}
.video-card:hover .video-thumb img {
  transform: scale(1.06);
}
.video-overlay {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition);
}
.video-card:hover .video-overlay {
  background: rgba(0,0,0,0.45);
}
.video-play-btn {
  width: 52px;
  height: 52px;
  background: var(--gradient);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  color: #fff;
  opacity: 0;
  transform: scale(0.7);
  transition: all var(--transition);
  padding-left: 3px;
  box-shadow: 0 4px 20px rgba(233,30,140,0.5);
}
.video-card:hover .video-play-btn {
  opacity: 1;
  transform: scale(1);
}
.video-tag {
  position: absolute;
  top: 8px;
  left: 8px;
  background: rgba(233,30,140,0.85);
  color: #fff;
  padding: 3px 10px;
  border-radius: 10px;
  font-size: 0.72rem;
  font-weight: 600;
  backdrop-filter: blur(4px);
}
.video-duration {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(0,0,0,0.75);
  color: #fff;
  padding: 2px 8px;
  border-radius: 6px;
  font-size: 0.72rem;
  font-weight: 600;
  backdrop-filter: blur(4px);
}
.video-info {
  padding: 12px 14px;
}
.video-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 8px;
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.video-meta {
  display: flex;
  gap: 10px;
  font-size: 0.75rem;
  color: var(--text-muted);
  flex-wrap: wrap;
}
.badge {
  padding: 3px 8px;
  border-radius: 6px;
  font-size: 0.7rem;
  font-weight: 700;
}
.badge-hot { background: #FF4444; color: #fff; }
.badge-new { background: #00C853; color: #fff; }
.badge-award { background: #FFB800; color: #000; }

/* ===== 功能卡片 ===== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 20px;
}
.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: all var(--transition);
}
.feature-card:hover {
  border-color: rgba(233,30,140,0.3);
  transform: translateY(-3px);
  box-shadow: var(--shadow-card);
}
.feature-icon {
  font-size: 2rem;
  margin-bottom: 12px;
}
.feature-card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text);
}
.feature-card p {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ===== AI赋能 ===== */
.ai-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}
.ai-img {
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
}
.ai-img img {
  width: 100%;
  height: 380px;
  object-fit: cover;
}
.ai-features {
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.ai-feature-item {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  transition: border-color var(--transition);
}
.ai-feature-item:hover { border-color: rgba(233,30,140,0.3); }
.ai-feature-icon {
  font-size: 1.4rem;
  flex-shrink: 0;
  margin-top: 2px;
}
.ai-feature-item h4 {
  font-size: 0.9rem;
  font-weight: 700;
  margin-bottom: 4px;
}
.ai-feature-item p {
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ===== 社区功能 ===== */
.community-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 16px;
}
.community-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  text-align: center;
  transition: all var(--transition);
}
.community-card:hover {
  border-color: rgba(233,30,140,0.3);
  transform: translateY(-3px);
}
.community-icon {
  font-size: 2rem;
  margin-bottom: 10px;
}
.community-card h4 {
  font-size: 0.92rem;
  font-weight: 700;
  margin-bottom: 6px;
}
.community-card p {
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ===== 专家团队 ===== */
.expert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 20px;
}
.expert-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 20px;
  text-align: center;
  transition: all var(--transition);
}
.expert-card:hover {
  border-color: rgba(233,30,140,0.3);
  transform: translateY(-3px);
  box-shadow: var(--shadow-card);
}
.expert-avatar {
  width: 80px;
  height: 80px;
  background: var(--gradient);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  margin: 0 auto 14px;
}
.expert-name {
  font-size: 1.1rem;
  font-weight: 800;
  margin-bottom: 4px;
}
.expert-role {
  font-size: 0.82rem;
  color: var(--primary-light);
  margin-bottom: 10px;
  font-weight: 600;
}
.expert-desc {
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 14px;
}
.expert-btns {
  display: flex;
  gap: 8px;
  justify-content: center;
}
.btn-sm {
  padding: 7px 14px;
  border-radius: 16px;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
}
.btn-sm-primary {
  background: var(--gradient);
  color: #fff;
  border: none;
}
.btn-sm-outline {
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--border);
}
.btn-sm-outline:hover {
  border-color: var(--primary);
  color: var(--primary-light);
}

/* ===== 合作伙伴 ===== */
.partner-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 12px;
}
.partner-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 16px;
  text-align: center;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-muted);
  transition: all var(--transition);
}
.partner-item:hover {
  border-color: rgba(233,30,140,0.3);
  color: var(--text);
}

/* ===== 加入步骤 ===== */
.join-steps {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 20px;
}
.join-step {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  text-align: center;
  transition: border-color var(--transition);
}
.join-step:hover { border-color: rgba(233,30,140,0.3); }
.step-num {
  width: 44px;
  height: 44px;
  background: var(--gradient);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  font-weight: 900;
  color: #fff;
  margin: 0 auto 12px;
}
.join-step h4 {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 6px;
}
.join-step p {
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ===== 联系我们 ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: start;
}
.contact-info h3 {
  font-size: 1.2rem;
  font-weight: 800;
  margin-bottom: 20px;
  background: var(--gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.contact-item {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  margin-bottom: 16px;
  padding: 14px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: border-color var(--transition);
}
.contact-item:hover { border-color: rgba(233,30,140,0.3); }
.contact-icon {
  font-size: 1.2rem;
  flex-shrink: 0;
  margin-top: 2px;
}
.contact-item .label {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 2px;
}
.contact-item .value {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text);
}

/* ===== 二维码 ===== */
.qrcode-row {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}
.qrcode-item {
  text-align: center;
}
.qrcode-item img {
  width: 100px;
  height: 100px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: #fff;
  padding: 4px;
}
.qrcode-item p {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 6px;
}

/* ===== 用户评价 ===== */
.review-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}
.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  transition: border-color var(--transition);
}
.review-card:hover { border-color: rgba(233,30,140,0.3); }
.review-header {
  display: flex;
  gap: 12px;
  align-items: center;
  margin-bottom: 10px;
}
.review-avatar {
  width: 44px;
  height: 44px;
  background: var(--gradient);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}
.review-user-info .name {
  font-size: 0.9rem;
  font-weight: 700;
}
.review-user-info .date {
  font-size: 0.75rem;
  color: var(--text-muted);
}
.review-stars {
  font-size: 0.85rem;
  margin-bottom: 8px;
  color: #FFB800;
}
.review-text {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ===== FAQ ===== */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: border-color var(--transition);
}
.faq-item.open { border-color: rgba(233,30,140,0.3); }
.faq-question {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
  transition: color var(--transition);
  gap: 12px;
}
.faq-question:hover { color: var(--primary-light); }
.faq-icon {
  font-size: 1.2rem;
  font-weight: 400;
  color: var(--primary);
  flex-shrink: 0;
  transition: transform var(--transition);
}
.faq-item.open .faq-icon { transform: rotate(45deg); }
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.7;
  padding: 0 20px;
}
.faq-item.open .faq-answer {
  max-height: 300px;
  padding: 0 20px 16px;
}

/* ===== 分享区 ===== */
.share-section {
  background: var(--bg-card);
  border-top: 1px solid var(--border);
  padding: 24px 0;
  text-align: center;
}
.share-title {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}
.share-btns {
  display: flex;
  gap: 10px;
  justify-content: center;
  flex-wrap: wrap;
}
.share-btn {
  background: var(--bg-card2);
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 8px 18px;
  border-radius: 20px;
  font-size: 0.85rem;
  cursor: pointer;
  transition: all var(--transition);
  display: flex;
  align-items: center;
  gap: 6px;
}
.share-btn:hover {
  border-color: rgba(233,30,140,0.4);
  color: var(--primary-light);
}

/* ===== 页脚 ===== */
.site-footer {
  background: var(--bg-card);
  border-top: 1px solid var(--border);
  padding: 48px 0 0;
}
.footer-grid {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px 40px;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
}
.footer-brand p {
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 10px;
}
.footer-col h4 {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text);
}
.footer-col ul li {
  margin-bottom: 8px;
}
.footer-col ul li a {
  font-size: 0.85rem;
  color: var(--text-muted);
  transition: color var(--transition);
}
.footer-col ul li a:hover { color: var(--primary-light); }
.footer-bottom {
  border-top: 1px solid var(--border);
  padding: 20px;
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-muted);
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.footer-bottom a {
  color: var(--text-muted);
  transition: color var(--transition);
}
.footer-bottom a:hover { color: var(--primary-light); }

/* ===== 面包屑 ===== */
.breadcrumb {
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
}
.breadcrumb-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 12px 20px;
  font-size: 0.82rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
}
.breadcrumb-inner a { color: var(--text-muted); }
.breadcrumb-inner a:hover { color: var(--primary-light); }
.breadcrumb-inner .sep { color: var(--text-dim); }
.breadcrumb-inner .current { color: var(--text); font-weight: 600; }

/* ===== 页面Hero（内页）===== */
.page-hero {
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  padding: 48px 20px;
  text-align: center;
  max-width: 100%;
}
.page-hero h1 {
  font-size: clamp(1.8rem, 3vw, 2.8rem);
  font-weight: 900;
  margin-bottom: 12px;
}
.page-hero p {
  font-size: 0.95rem;
  color: var(--text-muted);
  max-width: 700px;
  margin: 0 auto;
  line-height: 1.8;
}

/* ===== 内页内容 ===== */
.inner-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 40px 20px 60px;
}
.inner-intro {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 36px;
  line-height: 1.8;
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* ===== 动画 ===== */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}
.animate-on-scroll {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.animate-on-scroll.animate-in {
  opacity: 1;
  transform: translateY(0);
}
img.loaded { animation: fadeInUp 0.4s ease; }

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .ai-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
  .hamburger { display: flex; }
  .main-nav {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: rgba(13,13,26,0.98);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 16px;
    gap: 4px;
    z-index: 999;
  }
  .main-nav.open { display: flex; }
  .main-nav a {
    width: 100%;
    padding: 12px 16px;
    border-radius: var(--radius-sm);
  }
  .hero-content { grid-template-columns: 1fr; }
  .hero-video-preview { display: none; }
  .hero-text h1 { font-size: 2rem; }
  .hero-stats { gap: 16px; }
  .footer-grid { grid-template-columns: 1fr; gap: 24px; }
  .video-grid { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }
  .feature-grid { grid-template-columns: 1fr 1fr; }
  .expert-grid { grid-template-columns: 1fr 1fr; }
  .join-steps { grid-template-columns: 1fr 1fr; }
  .search-bar-inner { flex-direction: column; align-items: stretch; }
  .search-form { max-width: 100%; }
}
@media (max-width: 480px) {
  .feature-grid { grid-template-columns: 1fr; }
  .expert-grid { grid-template-columns: 1fr; }
  .join-steps { grid-template-columns: 1fr; }
  .community-grid { grid-template-columns: 1fr 1fr; }
  .video-grid { grid-template-columns: 1fr; }
  .hero-stats { gap: 12px; }
  .stat-num { font-size: 1.4rem; }
  .section { padding: 40px 0; }
  .page-hero { padding: 32px 16px; }
}

/* ===== 打印样式 ===== */
@media print {
  .site-header, .search-bar-wrap, .share-section, .hamburger { display: none; }
  body { background: #fff; color: #000; }
}