/* ============================================================
   海角社区 游戏解说社区 - 原创样式
   主题：深蓝+金色游戏风
   域名：bdweld.cn
   ============================================================ */

/* ---- 全局重置与变量 ---- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary:    #1A2744;
  --accent:     #F0B429;
  --secondary:  #2D4A8A;
  --bg-dark:    #0D1B2A;
  --bg-card:    #162035;
  --text-main:  #E8EDF5;
  --text-muted: #8A9BB8;
  --border:     rgba(240,180,41,0.25);
  --glow:       0 0 18px rgba(240,180,41,0.35);
  --radius:     10px;
  --radius-lg:  18px;
  --trans:      0.28s ease;
}

html { scroll-behavior: smooth; }

body {
  font-family: "PingFang SC","Microsoft YaHei","Hiragino Sans GB",sans-serif;
  background: var(--bg-dark);
  color: var(--text-main);
  line-height: 1.7;
  font-size: 15px;
  overflow-x: hidden;
}

a { color: var(--accent); text-decoration: none; transition: color var(--trans); }
a:hover { color: #ffd166; }
img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }

/* ---- 滚动条 ---- */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-dark); }
::-webkit-scrollbar-thumb { background: var(--secondary); border-radius: 3px; }

/* ============================================================
   顶部导航
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(13,27,42,0.96);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 2px 20px rgba(0,0,0,0.5);
}

.header-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 20px;
  height: 66px;
  display: flex;
  align-items: center;
  gap: 24px;
}

/* Logo区域 */
.logo-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
  text-decoration: none;
}
.logo-wrap img.logo-img {
  width: 40px;
  height: 40px;
  border-radius: 8px;
  object-fit: cover;
}
.logo-wrap .logo-favicon {
  width: 20px;
  height: 20px;
  border-radius: 4px;
}
.logo-text {
  font-size: 20px;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: 0.5px;
  white-space: nowrap;
}
.logo-text span { color: #fff; }

/* 主导航 */
.main-nav {
  display: flex;
  align-items: center;
  gap: 4px;
  flex: 1;
}
.main-nav a {
  color: var(--text-main);
  font-size: 14px;
  padding: 6px 14px;
  border-radius: 6px;
  transition: all var(--trans);
  white-space: nowrap;
}
.main-nav a:hover,
.main-nav a.active {
  color: var(--accent);
  background: rgba(240,180,41,0.1);
}

/* 搜索框 */
.search-wrap {
  display: flex;
  align-items: center;
  background: rgba(45,74,138,0.3);
  border: 1px solid var(--border);
  border-radius: 24px;
  overflow: hidden;
  flex-shrink: 0;
}
.search-wrap input {
  background: transparent;
  border: none;
  outline: none;
  color: var(--text-main);
  padding: 7px 14px;
  font-size: 13px;
  width: 180px;
}
.search-wrap input::placeholder { color: var(--text-muted); }
.search-wrap button {
  background: var(--accent);
  border: none;
  color: var(--primary);
  padding: 7px 14px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 700;
  transition: background var(--trans);
}
.search-wrap button:hover { background: #ffd166; }

/* 汉堡菜单 */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  flex-direction: column;
  gap: 5px;
  padding: 4px;
}
.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
  transition: all var(--trans);
}

/* ============================================================
   搜索提示
   ============================================================ */
.search-toast {
  position: fixed;
  top: 80px;
  left: 50%;
  transform: translateX(-50%) translateY(-20px);
  background: var(--secondary);
  color: #fff;
  padding: 10px 24px;
  border-radius: 24px;
  font-size: 14px;
  opacity: 0;
  pointer-events: none;
  transition: all 0.3s ease;
  z-index: 9999;
  border: 1px solid var(--border);
}
.search-toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ============================================================
   Hero Banner
   ============================================================ */
.hero-section {
  position: relative;
  min-height: 580px;
  display: flex;
  align-items: center;
  overflow: hidden;
}
.hero-bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  z-index: 0;
}
.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(13,27,42,0.88) 0%, rgba(26,39,68,0.65) 60%, rgba(13,27,42,0.4) 100%);
  z-index: 1;
}
.hero-content {
  position: relative;
  z-index: 2;
  max-width: 1280px;
  margin: 0 auto;
  padding: 80px 20px;
  width: 100%;
}
.hero-badge {
  display: inline-block;
  background: rgba(240,180,41,0.15);
  border: 1px solid var(--accent);
  color: var(--accent);
  font-size: 12px;
  padding: 4px 14px;
  border-radius: 20px;
  margin-bottom: 18px;
  letter-spacing: 1px;
}
.hero-content h1 {
  font-size: clamp(32px, 5vw, 58px);
  font-weight: 900;
  line-height: 1.15;
  margin-bottom: 16px;
  text-shadow: 0 2px 20px rgba(0,0,0,0.6);
}
.hero-content h1 .brand-highlight {
  color: var(--accent);
  text-shadow: var(--glow);
}
.hero-subtitle {
  font-size: clamp(15px, 2vw, 18px);
  color: rgba(232,237,245,0.85);
  max-width: 580px;
  margin-bottom: 32px;
  line-height: 1.8;
}
.hero-btns {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}
.btn-primary {
  background: linear-gradient(135deg, var(--accent), #e09000);
  color: var(--primary);
  font-weight: 700;
  padding: 12px 32px;
  border-radius: 8px;
  font-size: 15px;
  transition: all var(--trans);
  box-shadow: 0 4px 16px rgba(240,180,41,0.4);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(240,180,41,0.5);
  color: var(--primary);
}
.btn-outline {
  border: 2px solid var(--accent);
  color: var(--accent);
  padding: 11px 28px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 600;
  transition: all var(--trans);
}
.btn-outline:hover {
  background: rgba(240,180,41,0.1);
  color: var(--accent);
}

/* ============================================================
   数据统计条
   ============================================================ */
.stats-bar {
  background: linear-gradient(90deg, var(--secondary), #1e3a6e);
  padding: 22px 20px;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}
.stats-inner {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  justify-content: space-around;
  flex-wrap: wrap;
  gap: 16px;
  text-align: center;
}
.stat-item h3 {
  font-size: 28px;
  font-weight: 800;
  color: var(--accent);
  text-shadow: var(--glow);
}
.stat-item p {
  font-size: 13px;
  color: var(--text-muted);
  margin-top: 2px;
}

/* ============================================================
   通用区块
   ============================================================ */
.section {
  padding: 64px 20px;
}
.section-alt {
  padding: 64px 20px;
  background: rgba(22,32,53,0.6);
}
.container {
  max-width: 1280px;
  margin: 0 auto;
}
.section-header {
  text-align: center;
  margin-bottom: 44px;
}
.section-tag {
  display: inline-block;
  background: rgba(240,180,41,0.12);
  border: 1px solid rgba(240,180,41,0.4);
  color: var(--accent);
  font-size: 12px;
  padding: 3px 12px;
  border-radius: 20px;
  margin-bottom: 10px;
  letter-spacing: 1px;
}
.section-title {
  font-size: clamp(22px, 3.5vw, 34px);
  font-weight: 800;
  color: #fff;
  margin-bottom: 10px;
}
.section-title .accent { color: var(--accent); }
.section-desc {
  color: var(--text-muted);
  font-size: 15px;
  max-width: 560px;
  margin: 0 auto;
}

/* ============================================================
   视频卡片网格
   ============================================================ */
.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}
.video-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid rgba(45,74,138,0.4);
  transition: all var(--trans);
  cursor: pointer;
}
.video-card:hover {
  transform: translateY(-6px);
  border-color: var(--accent);
  box-shadow: 0 12px 32px rgba(240,180,41,0.2);
}
.video-thumb {
  position: relative;
  aspect-ratio: 16/9;
  overflow: hidden;
}
.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); }
.play-overlay {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity var(--trans);
}
.video-card:hover .play-overlay { opacity: 1; }
.play-btn-icon {
  width: 56px;
  height: 56px;
  background: rgba(240,180,41,0.9);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 20px rgba(240,180,41,0.5);
}
.play-btn-icon::after {
  content: '';
  width: 0;
  height: 0;
  border-top: 11px solid transparent;
  border-bottom: 11px solid transparent;
  border-left: 18px solid var(--primary);
  margin-left: 4px;
}
.video-tag {
  position: absolute;
  top: 10px;
  left: 10px;
  background: var(--accent);
  color: var(--primary);
  font-size: 11px;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 4px;
}
.video-duration {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(0,0,0,0.75);
  color: #fff;
  font-size: 11px;
  padding: 2px 7px;
  border-radius: 4px;
}
.video-info {
  padding: 14px 16px;
}
.video-info h3 {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-main);
  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-meta span { display: flex; align-items: center; gap: 4px; }

/* ============================================================
   功能卡片（4列）
   ============================================================ */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 20px;
}
.feature-card {
  background: var(--bg-card);
  border: 1px solid rgba(45,74,138,0.4);
  border-radius: var(--radius-lg);
  padding: 28px 22px;
  text-align: center;
  transition: all var(--trans);
}
.feature-card:hover {
  border-color: var(--accent);
  box-shadow: var(--glow);
  transform: translateY(-4px);
}
.feature-icon {
  font-size: 38px;
  margin-bottom: 14px;
  display: block;
}
.feature-card h3 {
  font-size: 16px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 8px;
}
.feature-card p {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.7;
}

/* ============================================================
   专家卡片
   ============================================================ */
.expert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
}
.expert-card {
  background: var(--bg-card);
  border: 1px solid rgba(45,74,138,0.4);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: all var(--trans);
  display: flex;
  gap: 18px;
  align-items: flex-start;
}
.expert-card:hover {
  border-color: var(--accent);
  box-shadow: var(--glow);
}
.expert-avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--accent);
  flex-shrink: 0;
}
.expert-info h3 {
  font-size: 17px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 4px;
}
.expert-role {
  font-size: 12px;
  color: var(--accent);
  margin-bottom: 8px;
  font-weight: 600;
}
.expert-desc {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 10px;
}
.expert-award {
  font-size: 12px;
  color: #ffd166;
  background: rgba(240,180,41,0.1);
  padding: 3px 10px;
  border-radius: 4px;
  display: inline-block;
  margin-bottom: 10px;
}
.expert-btns {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.btn-sm {
  font-size: 12px;
  padding: 5px 14px;
  border-radius: 6px;
  font-weight: 600;
  transition: all var(--trans);
}
.btn-sm-primary {
  background: var(--accent);
  color: var(--primary);
}
.btn-sm-primary:hover { background: #ffd166; color: var(--primary); }
.btn-sm-outline {
  border: 1px solid var(--border);
  color: var(--text-muted);
}
.btn-sm-outline:hover { border-color: var(--accent); color: var(--accent); }

/* ============================================================
   合作伙伴Logo墙
   ============================================================ */
.partner-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 16px;
}
.partner-item {
  background: var(--bg-card);
  border: 1px solid rgba(45,74,138,0.3);
  border-radius: var(--radius);
  padding: 18px 12px;
  text-align: center;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  transition: all var(--trans);
}
.partner-item:hover {
  border-color: var(--accent);
  color: var(--accent);
}
.partner-item span {
  display: block;
  font-size: 24px;
  margin-bottom: 6px;
}

/* ============================================================
   联系我们
   ============================================================ */
.contact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}
.contact-card {
  background: var(--bg-card);
  border: 1px solid rgba(45,74,138,0.4);
  border-radius: var(--radius-lg);
  padding: 28px;
}
.contact-card h3 {
  font-size: 17px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}
.contact-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 12px;
  font-size: 14px;
  color: var(--text-muted);
}
.contact-item .ci-icon {
  font-size: 16px;
  flex-shrink: 0;
  margin-top: 1px;
}
.contact-item strong { color: var(--text-main); }

/* ============================================================
   用户评价
   ============================================================ */
.comment-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}
.comment-card {
  background: var(--bg-card);
  border: 1px solid rgba(45,74,138,0.3);
  border-radius: var(--radius-lg);
  padding: 22px;
  transition: all var(--trans);
}
.comment-card:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 16px rgba(240,180,41,0.1);
}
.comment-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}
.comment-user { font-weight: 700; color: #fff; font-size: 14px; }
.comment-stars { color: var(--accent); font-size: 14px; }
.comment-text { font-size: 13px; color: var(--text-muted); line-height: 1.8; }

/* ============================================================
   FAQ
   ============================================================ */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: var(--bg-card);
  border: 1px solid rgba(45,74,138,0.3);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
  transition: border-color var(--trans);
}
.faq-item:hover { border-color: var(--accent); }
.faq-q {
  padding: 16px 20px;
  font-weight: 600;
  font-size: 15px;
  color: var(--text-main);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
}
.faq-q::after {
  content: '+';
  color: var(--accent);
  font-size: 20px;
  flex-shrink: 0;
  transition: transform var(--trans);
}
.faq-item.open .faq-q::after { transform: rotate(45deg); }
.faq-a {
  padding: 0 20px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.8;
}
.faq-item.open .faq-a {
  max-height: 300px;
  padding: 0 20px 16px;
}

/* ============================================================
   How-To 指南
   ============================================================ */
.howto-steps {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 20px;
  counter-reset: step;
}
.howto-step {
  background: var(--bg-card);
  border: 1px solid rgba(45,74,138,0.3);
  border-radius: var(--radius-lg);
  padding: 24px 20px;
  position: relative;
  transition: all var(--trans);
}
.howto-step:hover { border-color: var(--accent); }
.step-num {
  width: 36px;
  height: 36px;
  background: var(--accent);
  color: var(--primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 16px;
  margin-bottom: 12px;
}
.howto-step h4 {
  font-size: 15px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 6px;
}
.howto-step p {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.7;
}

/* ============================================================
   二维码区域
   ============================================================ */
.qr-grid {
  display: flex;
  justify-content: center;
  gap: 40px;
  flex-wrap: wrap;
}
.qr-item {
  text-align: center;
}
.qr-box {
  width: 120px;
  height: 120px;
  background: var(--bg-card);
  border: 2px solid var(--border);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 10px;
  font-size: 50px;
}
.qr-item p {
  font-size: 13px;
  color: var(--text-muted);
}

/* ============================================================
   社交分享
   ============================================================ */
.share-bar {
  display: flex;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
  padding: 20px;
}
.share-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 18px;
  border-radius: 24px;
  font-size: 13px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: all var(--trans);
}
.share-wechat  { background: #07c160; color: #fff; }
.share-weibo   { background: #e6162d; color: #fff; }
.share-douyin  { background: #010101; color: #fff; border: 1px solid #333; }
.share-bilibili{ background: #00a1d6; color: #fff; }
.share-btn:hover { opacity: 0.85; transform: translateY(-2px); }

/* ============================================================
   视频播放弹窗
   ============================================================ */
.video-modal {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.85);
  z-index: 9998;
  align-items: center;
  justify-content: center;
}
.video-modal.active { display: flex; }
.modal-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  max-width: 560px;
  width: 90%;
  text-align: center;
  position: relative;
}
.modal-close {
  position: absolute;
  top: 12px;
  right: 16px;
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 24px;
  cursor: pointer;
  transition: color var(--trans);
}
.modal-close:hover { color: var(--accent); }
.modal-play-btn {
  width: 72px;
  height: 72px;
  background: var(--accent);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 16px auto;
  cursor: pointer;
  box-shadow: 0 4px 20px rgba(240,180,41,0.4);
  transition: transform var(--trans);
}
.modal-play-btn:hover { transform: scale(1.1); }
.modal-play-btn::after {
  content: '';
  width: 0;
  height: 0;
  border-top: 13px solid transparent;
  border-bottom: 13px solid transparent;
  border-left: 22px solid var(--primary);
  margin-left: 5px;
}
.modal-title {
  font-size: 17px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 8px;
}
.modal-desc {
  font-size: 13px;
  color: var(--text-muted);
}

/* ============================================================
   面包屑
   ============================================================ */
.breadcrumb {
  max-width: 1280px;
  margin: 0 auto;
  padding: 14px 20px;
  font-size: 13px;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
}
.breadcrumb a { color: var(--text-muted); }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb .sep { color: rgba(138,155,184,0.4); }
.breadcrumb .current { color: var(--accent); }

/* ============================================================
   内页头部
   ============================================================ */
.page-hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  padding: 48px 20px;
  border-bottom: 1px solid var(--border);
}
.page-hero h1 {
  font-size: clamp(24px, 4vw, 38px);
  font-weight: 800;
  color: #fff;
  margin-bottom: 8px;
}
.page-hero p {
  color: var(--text-muted);
  font-size: 15px;
  max-width: 600px;
}

/* ============================================================
   页脚
   ============================================================ */
.site-footer {
  background: rgba(10,18,30,0.98);
  border-top: 1px solid var(--border);
  padding: 48px 20px 24px;
}
.footer-inner {
  max-width: 1280px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 32px;
  margin-bottom: 32px;
}
.footer-col h4 {
  font-size: 15px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}
.footer-col p,
.footer-col li {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 8px;
  line-height: 1.7;
}
.footer-col a { color: var(--text-muted); }
.footer-col a:hover { color: var(--accent); }
.footer-bottom {
  max-width: 1280px;
  margin: 0 auto;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 12px;
  color: var(--text-muted);
}
.footer-links {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}
.footer-links a { color: var(--text-muted); font-size: 12px; }
.footer-links a:hover { color: var(--accent); }

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 900px) {
  .main-nav { display: none; }
  .main-nav.open {
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 66px;
    left: 0;
    right: 0;
    background: rgba(13,27,42,0.98);
    padding: 16px 20px;
    border-bottom: 1px solid var(--border);
    z-index: 999;
    gap: 4px;
  }
  .main-nav.open a { padding: 10px 14px; }
  .nav-toggle { display: flex; }
  .search-wrap { display: none; }
  .hero-section { min-height: 420px; }
  .stats-inner { gap: 20px; }
  .stat-item h3 { font-size: 22px; }
}

@media (max-width: 600px) {
  .header-inner { gap: 12px; }
  .logo-text { font-size: 17px; }
  .hero-content { padding: 50px 16px; }
  .section, .section-alt { padding: 44px 16px; }
  .video-grid { grid-template-columns: 1fr 1fr; gap: 12px; }
  .expert-card { flex-direction: column; }
  .footer-inner { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 400px) {
  .video-grid { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr; }
}

/* ============================================================
   工具类
   ============================================================ */
.text-center { text-align: center; }
.mt-8 { margin-top: 8px; }
.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }
.mt-32 { margin-top: 32px; }
.mb-8 { margin-bottom: 8px; }
.mb-16 { margin-bottom: 16px; }
.hidden { display: none !important; }