/* ============================================================
   四虎 (KunKunTu) - 全站样式
   主题：紫蓝赛车 / 四虎 - 四虎 - 四虎汽车改装视频社区官网官网
   域名：ztqhy.cn
   ============================================================ */

/* ---------- CSS变量 ---------- */
:root {
  --purple:    #6B21A8;
  --purple2:   #9333EA;
  --blue:      #3B82F6;
  --blue2:     #60A5FA;
  --dark:      #0D0D1A;
  --dark2:     #13132A;
  --dark3:     #1A1A35;
  --border:    rgba(107,33,168,0.25);
  --white:     #F8F8FF;
  --text-muted:#94A3B8;
  --radius:    8px;
  --radius-lg: 14px;
  --trans:     all 0.28s ease;
  --shadow:    0 4px 24px rgba(107,33,168,0.18);
}

/* ---------- 重置 ---------- */
*, *::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",sans-serif;
  background: var(--dark);
  color: var(--white);
  line-height: 1.7;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul, ol { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }

/* ---------- 干扰标签隐藏（不影响布局） ---------- */
.kktu-noise { display: none !important; visibility: hidden !important; }

/* ---------- 滚动条 ---------- */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--dark); }
::-webkit-scrollbar-thumb { background: var(--purple); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--purple2); }
::selection { background: var(--purple2); color: #fff; }

/* ---------- 容器 ---------- */
.container { max-width: 1280px; margin: 0 auto; padding: 0 20px; }
.section { padding: 70px 0; }
.section-sm { padding: 40px 0; }

/* ---------- 公告条 ---------- */
.notice-bar {
  background: linear-gradient(90deg, var(--purple) 0%, var(--blue) 100%);
  padding: 8px 0;
  text-align: center;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.5px;
}
.notice-bar a { color: #fff; text-decoration: underline; margin-left: 8px; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(13,13,26,0.96);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 16px;
}
.site-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
.site-logo img { height: 40px; width: auto; border-radius: 6px; }
.logo-text {
  font-size: 20px;
  font-weight: 900;
  background: linear-gradient(135deg, var(--purple2), var(--blue2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 1px;
}
.logo-sub { font-size: 11px; color: var(--text-muted); display: block; margin-top: -4px; }

/* 导航 */
.main-nav {
  display: flex;
  align-items: center;
  gap: 4px;
}
.main-nav a {
  padding: 6px 12px;
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 600;
  color: var(--text-muted);
  transition: var(--trans);
  white-space: nowrap;
}
.main-nav a:hover,
.main-nav a.active {
  color: var(--white);
  background: rgba(107,33,168,0.2);
}

/* Header右侧按钮 */
.header-actions { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.btn-login {
  padding: 7px 18px;
  border-radius: 20px;
  border: 1px solid var(--purple);
  color: var(--purple2);
  font-size: 13px;
  font-weight: 700;
  transition: var(--trans);
}
.btn-login:hover { background: var(--purple); color: #fff; }
.btn-join {
  padding: 7px 18px;
  border-radius: 20px;
  background: linear-gradient(135deg, var(--purple), var(--blue));
  color: #fff;
  font-size: 13px;
  font-weight: 700;
  transition: var(--trans);
}
.btn-join:hover { opacity: 0.85; transform: translateY(-1px); }
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 6px;
}
.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--white);
  border-radius: 2px;
  transition: var(--trans);
}

/* ---------- 搜索栏 ---------- */
.search-bar-section {
  background: var(--dark2);
  border-bottom: 1px solid var(--border);
  padding: 10px 0;
}
.search-bar-inner {
  display: flex;
  align-items: center;
  gap: 12px;
}
.search-bar-main {
  flex: 1;
  display: flex;
  align-items: center;
  background: var(--dark3);
  border: 1px solid var(--border);
  border-radius: 24px;
  overflow: hidden;
  transition: var(--trans);
}
.search-bar-main:focus-within { border-color: var(--purple2); }
.search-bar-main input {
  flex: 1;
  background: none;
  border: none;
  outline: none;
  padding: 9px 16px;
  font-size: 14px;
  color: var(--white);
}
.search-bar-main input::placeholder { color: var(--text-muted); }
.search-bar-main button {
  padding: 9px 20px;
  background: linear-gradient(135deg, var(--purple), var(--blue));
  color: #fff;
  font-size: 13px;
  font-weight: 700;
  border-radius: 0 24px 24px 0;
  transition: var(--trans);
}
.search-bar-main button:hover { opacity: 0.85; }
.search-hot { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; font-size: 12px; }
.search-hot-label { color: var(--text-muted); white-space: nowrap; }
.search-hot a {
  padding: 3px 10px;
  border-radius: 12px;
  background: rgba(107,33,168,0.15);
  color: var(--purple2);
  font-size: 12px;
  transition: var(--trans);
}
.search-hot a:hover { background: var(--purple); color: #fff; }

/* 移动端搜索栏 */
.mobile-search-bar {
  display: none;
  padding: 10px 16px;
  background: var(--dark2);
  border-bottom: 1px solid var(--border);
}

/* ---------- Hero / Banner ---------- */
.hero {
  position: relative;
  min-height: 560px;
  display: flex;
  align-items: center;
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background-image: url('/images/banner.jpg');
  background-size: cover;
  background-position: center;
  filter: brightness(0.45);
  transform: scale(1.03);
  transition: transform 8s ease;
}
.hero:hover .hero-bg { transform: scale(1.0); }
.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(107,33,168,0.55) 0%, rgba(59,130,246,0.3) 100%);
}
.hero-content {
  position: relative;
  z-index: 2;
  padding: 60px 0;
  max-width: 700px;
}
.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(107,33,168,0.35);
  border: 1px solid rgba(147,51,234,0.5);
  border-radius: 20px;
  padding: 5px 14px;
  font-size: 12px;
  font-weight: 700;
  color: var(--blue2);
  letter-spacing: 1px;
  margin-bottom: 18px;
}
.hero-eyebrow::before { content: "▶"; font-size: 10px; }
.hero-title {
  font-size: clamp(28px, 5vw, 52px);
  font-weight: 900;
  line-height: 1.2;
  margin-bottom: 16px;
  text-shadow: 0 2px 20px rgba(0,0,0,0.5);
}
.hero-title em { font-style: normal; color: var(--purple2); }
.hero-desc {
  font-size: 16px;
  color: rgba(248,248,255,0.85);
  margin-bottom: 28px;
  line-height: 1.8;
  max-width: 560px;
}
.hero-btns { display: flex; gap: 14px; flex-wrap: wrap; }
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 28px;
  background: linear-gradient(135deg, var(--purple), var(--blue));
  color: #fff;
  font-size: 15px;
  font-weight: 700;
  transition: var(--trans);
  box-shadow: 0 4px 20px rgba(107,33,168,0.4);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 30px rgba(107,33,168,0.5); }
.btn-outline {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 28px;
  border: 2px solid rgba(248,248,255,0.5);
  color: #fff;
  font-size: 15px;
  font-weight: 700;
  transition: var(--trans);
}
.btn-outline:hover { border-color: var(--purple2); background: rgba(107,33,168,0.2); }
.hero-stats {
  display: flex;
  gap: 32px;
  margin-top: 32px;
  flex-wrap: wrap;
}
.hero-stat-item { text-align: center; }
.hero-stat-num {
  font-size: 26px;
  font-weight: 900;
  background: linear-gradient(135deg, var(--purple2), var(--blue2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-stat-label { font-size: 12px; color: var(--text-muted); }

/* ---------- 标题组件 ---------- */
.section-header { text-align: center; margin-bottom: 40px; }
.section-tag {
  display: inline-block;
  padding: 4px 14px;
  border-radius: 12px;
  background: rgba(107,33,168,0.15);
  border: 1px solid rgba(147,51,234,0.3);
  color: var(--purple2);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1px;
  margin-bottom: 10px;
}
.section-title {
  font-size: clamp(22px, 3.5vw, 36px);
  font-weight: 900;
  color: var(--white);
  margin-bottom: 10px;
}
.section-title em { font-style: normal; color: var(--purple2); }
.section-desc { font-size: 15px; color: var(--text-muted); max-width: 560px; margin: 0 auto; }

/* ---------- 视频卡片 ---------- */
.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}
.video-card {
  background: var(--dark2);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  transition: var(--trans);
  cursor: pointer;
}
.video-card:hover { transform: translateY(-5px); border-color: var(--purple2); box-shadow: var(--shadow); }
.video-thumb {
  position: relative;
  aspect-ratio: 16/9;
  overflow: hidden;
  background: var(--dark3);
}
.video-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
  loading: lazy;
}
.video-card:hover .video-thumb img { transform: scale(1.06); }
.video-play-btn {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.4);
  opacity: 0;
  transition: var(--trans);
}
.video-card:hover .video-play-btn { opacity: 1; }
.play-icon {
  width: 56px;
  height: 56px;
  background: rgba(107,33,168,0.9);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transform: scale(0.8);
  transition: var(--trans);
  box-shadow: 0 0 30px rgba(107,33,168,0.6);
}
.video-card:hover .play-icon { transform: scale(1); }
.play-icon::after {
  content: "";
  border-style: solid;
  border-width: 10px 0 10px 18px;
  border-color: transparent transparent transparent #fff;
  margin-left: 4px;
}
.video-duration {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(0,0,0,0.75);
  color: #fff;
  font-size: 12px;
  font-weight: 700;
  padding: 2px 7px;
  border-radius: 4px;
}
.video-badge {
  position: absolute;
  top: 8px;
  left: 8px;
  padding: 3px 8px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.5px;
}
.badge-hot { background: #EF4444; color: #fff; }
.badge-new { background: var(--purple); color: #fff; }
.badge-4k  { background: var(--blue); color: #fff; }
.video-info { padding: 14px; }
.video-tags { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 8px; }
.video-tag {
  padding: 2px 8px;
  border-radius: 10px;
  background: rgba(107,33,168,0.12);
  color: var(--purple2);
  font-size: 11px;
  font-weight: 600;
}
.video-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 8px;
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.video-meta {
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  color: var(--text-muted);
}
.video-stats { display: flex; gap: 10px; }
.video-stat { display: flex; align-items: center; gap: 3px; }

/* ---------- 统计数字行 ---------- */
.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  background: var(--dark2);
  border-radius: var(--radius-lg);
  padding: 30px;
  border: 1px solid var(--border);
}
.stat-item { text-align: center; }
.stat-num {
  font-size: 32px;
  font-weight: 900;
  background: linear-gradient(135deg, var(--purple2), var(--blue2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.stat-label { font-size: 13px; color: var(--text-muted); margin-top: 4px; }

/* ---------- 功能模块卡片 ---------- */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 20px;
}
.feature-card {
  background: var(--dark2);
  border-radius: var(--radius-lg);
  padding: 28px 20px;
  border: 1px solid var(--border);
  text-align: center;
  transition: var(--trans);
}
.feature-card:hover { border-color: var(--purple2); transform: translateY(-4px); box-shadow: var(--shadow); }
.feature-icon {
  font-size: 42px;
  margin-bottom: 14px;
  display: block;
}
.feature-title { font-size: 16px; font-weight: 800; color: var(--white); margin-bottom: 8px; }
.feature-desc { font-size: 13px; color: var(--text-muted); line-height: 1.6; }

/* ---------- AI模块 ---------- */
.ai-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
}
.ai-card {
  background: linear-gradient(135deg, var(--dark2) 0%, rgba(107,33,168,0.08) 100%);
  border-radius: var(--radius-lg);
  padding: 24px;
  border: 1px solid rgba(107,33,168,0.2);
  transition: var(--trans);
}
.ai-card:hover { border-color: var(--purple2); box-shadow: var(--shadow); }
.ai-icon { font-size: 36px; margin-bottom: 12px; }
.ai-title { font-size: 16px; font-weight: 800; color: var(--white); margin-bottom: 8px; }
.ai-desc { font-size: 13px; color: var(--text-muted); line-height: 1.6; }
.ai-badge {
  display: inline-block;
  margin-top: 12px;
  padding: 3px 10px;
  border-radius: 10px;
  background: rgba(107,33,168,0.2);
  color: var(--purple2);
  font-size: 11px;
  font-weight: 700;
}

/* ---------- 专家卡片 ---------- */
.expert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 20px;
}
.expert-card {
  background: var(--dark2);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  text-align: center;
  transition: var(--trans);
}
.expert-card:hover { border-color: var(--purple2); transform: translateY(-4px); }
.expert-photo {
  aspect-ratio: 4/3;
  overflow: hidden;
}
.expert-photo img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.4s; }
.expert-card:hover .expert-photo img { transform: scale(1.05); }
.expert-info { padding: 16px; }
.expert-name { font-size: 16px; font-weight: 800; color: var(--white); margin-bottom: 4px; }
.expert-role { font-size: 12px; color: var(--purple2); font-weight: 700; margin-bottom: 8px; }
.expert-desc { font-size: 13px; color: var(--text-muted); line-height: 1.5; margin-bottom: 12px; }
.expert-awards { font-size: 12px; color: var(--blue2); margin-bottom: 12px; }
.expert-btns { display: flex; gap: 8px; justify-content: center; }
.btn-sm {
  padding: 5px 14px;
  border-radius: 14px;
  font-size: 12px;
  font-weight: 700;
  transition: var(--trans);
}
.btn-sm-primary { background: var(--purple); color: #fff; }
.btn-sm-primary:hover { background: var(--purple2); }
.btn-sm-outline { border: 1px solid var(--border); color: var(--text-muted); }
.btn-sm-outline:hover { border-color: var(--purple2); color: var(--white); }

/* ---------- 用户评价 ---------- */
.review-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}
.review-card {
  background: var(--dark2);
  border-radius: var(--radius-lg);
  padding: 22px;
  border: 1px solid var(--border);
  transition: var(--trans);
}
.review-card:hover { border-color: var(--purple2); }
.review-header { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; }
.review-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--purple), var(--blue));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  font-weight: 800;
  color: #fff;
  flex-shrink: 0;
}
.review-user { flex: 1; }
.review-name { font-size: 14px; font-weight: 700; color: var(--white); }
.review-date { font-size: 12px; color: var(--text-muted); }
.review-stars { color: #F59E0B; font-size: 14px; margin-bottom: 8px; }
.review-text { font-size: 13px; color: var(--text-muted); line-height: 1.7; }
.review-tag { margin-top: 10px; }
.review-tag span {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 10px;
  background: rgba(107,33,168,0.12);
  color: var(--purple2);
  font-size: 11px;
}

/* ---------- FAQ ---------- */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: var(--dark2);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  margin-bottom: 10px;
  overflow: hidden;
  transition: var(--trans);
}
.faq-item.open { border-color: var(--purple2); }
.faq-question {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  cursor: pointer;
  font-size: 15px;
  font-weight: 700;
  color: var(--white);
  user-select: none;
}
.faq-question:hover { color: var(--purple2); }
.faq-arrow {
  font-size: 18px;
  transition: transform 0.3s;
  color: var(--purple2);
  flex-shrink: 0;
}
.faq-item.open .faq-arrow { transform: rotate(180deg); }
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.3s;
  padding: 0 20px;
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.8;
}
.faq-item.open .faq-answer { max-height: 300px; padding: 0 20px 16px; }

/* ---------- 合作品牌 ---------- */
.partners-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  justify-content: center;
}
.partner-item {
  background: var(--dark2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 24px;
  font-size: 14px;
  font-weight: 700;
  color: var(--text-muted);
  transition: var(--trans);
  text-align: center;
  min-width: 120px;
}
.partner-item:hover { border-color: var(--purple2); color: var(--white); }

/* ---------- 社交分享 ---------- */
.share-row { display: flex; gap: 12px; flex-wrap: wrap; justify-content: center; }
.share-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 18px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 700;
  transition: var(--trans);
  border: 1px solid var(--border);
  color: var(--text-muted);
}
.share-btn:hover { border-color: var(--purple2); color: var(--white); background: rgba(107,33,168,0.15); }

/* ---------- 联系信息 ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 30px;
}
.contact-card {
  background: var(--dark2);
  border-radius: var(--radius-lg);
  padding: 28px;
  border: 1px solid var(--border);
}
.contact-title { font-size: 18px; font-weight: 800; color: var(--white); margin-bottom: 16px; }
.contact-item { display: flex; gap: 12px; margin-bottom: 12px; font-size: 14px; color: var(--text-muted); }
.contact-icon { font-size: 18px; flex-shrink: 0; }
.qr-row { display: flex; gap: 20px; flex-wrap: wrap; }
.qr-item { text-align: center; }
.qr-box {
  width: 100px;
  height: 100px;
  background: var(--dark3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 36px;
  margin-bottom: 6px;
}
.qr-label { font-size: 12px; color: var(--text-muted); }

/* ---------- 视频弹窗 ---------- */
.video-modal {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 9999;
  background: rgba(0,0,0,0.85);
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.video-modal.show { display: flex; }
.video-modal-inner {
  background: var(--dark2);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 800px;
  border: 1px solid var(--border);
  position: relative;
  overflow: hidden;
}
.video-modal-close {
  position: absolute;
  top: 12px;
  right: 14px;
  background: rgba(0,0,0,0.6);
  color: #fff;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  font-size: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10;
  cursor: pointer;
}
.video-modal-player {
  width: 100%;
  aspect-ratio: 16/9;
  background: #000;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 14px;
}
.video-modal-info { padding: 16px 20px; }
.video-modal-title { font-size: 16px; font-weight: 700; color: var(--white); margin-bottom: 6px; }
.video-modal-meta { font-size: 13px; color: var(--text-muted); }

/* ---------- 博客卡片 ---------- */
.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}
.blog-card {
  background: var(--dark2);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  transition: var(--trans);
}
.blog-card:hover { transform: translateY(-4px); border-color: var(--purple2); }
.blog-thumb { aspect-ratio: 16/9; overflow: hidden; }
.blog-thumb img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.4s; }
.blog-card:hover .blog-thumb img { transform: scale(1.05); }
.blog-body { padding: 16px; }
.blog-cat { font-size: 11px; color: var(--purple2); font-weight: 700; letter-spacing: 1px; text-transform: uppercase; margin-bottom: 6px; }
.blog-title { font-size: 15px; font-weight: 700; color: var(--white); margin-bottom: 8px; line-height: 1.5; }
.blog-excerpt { font-size: 13px; color: var(--text-muted); line-height: 1.6; margin-bottom: 12px; }
.blog-footer { display: flex; justify-content: space-between; font-size: 12px; color: var(--text-muted); }

/* ---------- 加入社区 ---------- */
.join-section {
  background: linear-gradient(135deg, var(--dark2) 0%, rgba(107,33,168,0.1) 100%);
  border-radius: var(--radius-lg);
  padding: 50px 40px;
  text-align: center;
  border: 1px solid rgba(107,33,168,0.2);
}
.join-title { font-size: 28px; font-weight: 900; color: var(--white); margin-bottom: 12px; }
.join-desc { font-size: 15px; color: var(--text-muted); margin-bottom: 28px; }
.join-steps { display: flex; justify-content: center; gap: 30px; margin-bottom: 30px; flex-wrap: wrap; }
.join-step { text-align: center; }
.join-step-num {
  width: 40px; height: 40px;
  background: linear-gradient(135deg, var(--purple), var(--blue));
  color: #fff;
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 16px; font-weight: 800;
  margin: 0 auto 8px;
}
.join-step-text { font-size: 13px; color: var(--text-muted); }

/* ---------- 面包屑 ---------- */
.breadcrumb {
  padding: 12px 0;
  font-size: 13px;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}
.breadcrumb a { color: var(--text-muted); transition: var(--trans); }
.breadcrumb a:hover { color: var(--purple2); }
.breadcrumb-sep { color: var(--border); }
.breadcrumb-current { color: var(--purple2); font-weight: 600; }

/* ---------- 内页Hero ---------- */
.page-hero {
  background: linear-gradient(135deg, var(--dark2) 0%, var(--dark3) 100%);
  padding: 50px 0 40px;
  border-bottom: 1px solid var(--border);
}
.page-hero-title { font-size: clamp(24px, 4vw, 40px); font-weight: 900; color: var(--white); margin-bottom: 10px; }
.page-hero-desc { font-size: 15px; color: var(--text-muted); }

/* ---------- Footer ---------- */
.site-footer {
  background: var(--dark2);
  border-top: 1px solid var(--border);
  padding: 50px 0 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 40px;
}
.footer-brand-name {
  font-size: 20px;
  font-weight: 900;
  background: linear-gradient(135deg, var(--purple2), var(--blue2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 10px;
}
.footer-brand-desc { font-size: 13px; color: var(--text-muted); line-height: 1.7; margin-bottom: 16px; }
.footer-social { display: flex; gap: 10px; }
.footer-social a {
  width: 34px; height: 34px;
  border-radius: 50%;
  background: var(--dark3);
  border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  font-size: 14px;
  transition: var(--trans);
}
.footer-social a:hover { border-color: var(--purple2); background: rgba(107,33,168,0.2); }
.footer-col-title { font-size: 14px; font-weight: 800; color: var(--white); margin-bottom: 14px; }
.footer-links { display: flex; flex-direction: column; gap: 8px; }
.footer-links a { font-size: 13px; color: var(--text-muted); transition: var(--trans); }
.footer-links a:hover { color: var(--purple2); }
.footer-bottom {
  border-top: 1px solid var(--border);
  padding: 18px 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 13px;
  color: var(--text-muted);
}
.footer-update { color: var(--purple2); font-weight: 600; }

/* ---------- SEO文本块 ---------- */
.seo-text-block {
  background: var(--dark2);
  border-radius: var(--radius-lg);
  padding: 28px;
  border: 1px solid var(--border);
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.9;
}
.seo-text-block h3 { font-size: 16px; color: var(--white); margin-bottom: 10px; font-weight: 700; }
.seo-text-block p { margin-bottom: 10px; }

/* ---------- 动画 ---------- */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(24px); }
  to   { opacity: 1; transform: translateY(0); }
}
.fade-in { animation: fadeInUp 0.6s ease both; }
.fade-in-1 { animation-delay: 0.1s; }
.fade-in-2 { animation-delay: 0.2s; }
.fade-in-3 { animation-delay: 0.3s; }
.fade-in-4 { animation-delay: 0.4s; }

@keyframes pulse-glow {
  0%, 100% { box-shadow: 0 0 10px rgba(107,33,168,0.3); }
  50% { box-shadow: 0 0 25px rgba(107,33,168,0.6); }
}
.pulse { animation: pulse-glow 2s ease infinite; }

/* ---------- 响应式 ---------- */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .stats-row { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .main-nav {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 64px;
    left: 0; right: 0;
    background: var(--dark2);
    padding: 16px;
    border-bottom: 1px solid var(--border);
    z-index: 999;
  }
  .main-nav.open { display: flex; }
  .menu-toggle { display: flex; }
  .header-search-form { display: none; }
  .search-bar-section { display: none; }
  .mobile-search-bar { display: block; }
  .hero { min-height: 380px; }
  .hero-content { padding: 40px 0; }
  .hero-stats { gap: 20px; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; text-align: center; }
  .video-grid { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }
  .expert-grid { grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); }
  .join-section { padding: 30px 20px; }
  .join-steps { gap: 16px; }
}
@media (max-width: 480px) {
  .video-grid { grid-template-columns: 1fr; }
  .hero-title { font-size: 24px; }
  .stats-row { grid-template-columns: 1fr 1fr; }
  .section { padding: 45px 0; }
  .hero-btns { flex-direction: column; }
}