/* ============================================================
   国产主播 - 汽车改装与视频社区
   主样式文件 | ejmor.cn
   ============================================================ */

/* ---- CSS变量 ---- */
:root {
  --color-primary: #FF6B2B;
  --color-primary-dark: #E05520;
  --color-secondary: #0A0E1A;
  --color-accent: #1A2540;
  --color-accent2: #2A3A60;
  --color-text: #1a1a2e;
  --color-text-light: #555e7a;
  --color-bg: #f5f6fa;
  --color-bg2: #eef0f7;
  --color-white: #ffffff;
  --color-border: #dde2f0;
  --color-gold: #f5c518;
  --font-main: 'PingFang SC','Microsoft YaHei','Helvetica Neue',Arial,sans-serif;
  --radius: 12px;
  --radius-sm: 6px;
  --shadow: 0 4px 24px rgba(10,14,26,0.10);
  --shadow-lg: 0 8px 40px rgba(10,14,26,0.18);
  --transition: 0.3s cubic-bezier(.4,0,.2,1);
}

/* ---- 重置 ---- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font-main);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  overflow-x: hidden;
}
a { color: inherit; text-decoration: none; transition: color var(--transition); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }
button, input, textarea, select { font-family: inherit; }

/* ---- 干扰标签隐藏 ---- */
.kktu-noise { display: none !important; visibility: hidden !important; position: absolute !important; left: -9999px !important; }

/* ============================================================
   顶部公告条
   ============================================================ */
.site-topbar {
  background: var(--color-secondary);
  color: rgba(255,255,255,0.75);
  font-size: 0.78rem;
  padding: 6px 0;
  text-align: center;
  letter-spacing: 0.03em;
}
.site-topbar a { color: var(--color-primary); }
.site-topbar .topbar-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ============================================================
   头部导航
   ============================================================ */
.site-header {
  background: var(--color-white);
  box-shadow: 0 2px 16px rgba(10,14,26,0.08);
  position: sticky;
  top: 0;
  z-index: 1000;
}
.header-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  gap: 24px;
  height: 70px;
}
.site-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
.site-logo img {
  height: 44px;
  width: auto;
}
.site-logo .logo-text {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--color-secondary);
  letter-spacing: -0.02em;
  line-height: 1.2;
}
.site-logo .logo-text span {
  color: var(--color-primary);
}
.site-logo .logo-sub {
  font-size: 0.7rem;
  color: var(--color-text-light);
  font-weight: 400;
}

/* 主导航 */
.main-nav {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}
.main-nav ul {
  display: flex;
  gap: 4px;
  align-items: center;
}
.main-nav ul li a {
  display: block;
  padding: 8px 14px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-text);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
  white-space: nowrap;
}
.main-nav ul li a:hover,
.main-nav ul li a.active {
  color: var(--color-primary);
  background: rgba(255,107,43,0.08);
}

/* 搜索框 */
.header-search {
  position: relative;
  flex-shrink: 0;
}
.header-search input {
  width: 200px;
  padding: 8px 40px 8px 14px;
  border: 1.5px solid var(--color-border);
  border-radius: 24px;
  font-size: 0.85rem;
  background: var(--color-bg);
  color: var(--color-text);
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.header-search input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(255,107,43,0.12);
}
.header-search .search-btn {
  position: absolute;
  right: 10px;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  cursor: pointer;
  color: var(--color-text-light);
  display: flex;
  align-items: center;
}
.header-search .search-btn:hover { color: var(--color-primary); }

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

/* 搜索提示 */
.search-tip {
  display: none;
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  right: 0;
  background: var(--color-white);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  font-size: 0.82rem;
  color: var(--color-text-light);
  box-shadow: var(--shadow);
  z-index: 200;
  white-space: nowrap;
}

/* ============================================================
   面包屑
   ============================================================ */
.breadcrumb {
  background: var(--color-bg2);
  padding: 10px 0;
  font-size: 0.82rem;
  color: var(--color-text-light);
  border-bottom: 1px solid var(--color-border);
}
.breadcrumb-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  align-items: center;
  gap: 6px;
}
.breadcrumb a { color: var(--color-primary); }
.breadcrumb span { color: var(--color-text-light); }

/* ============================================================
   容器
   ============================================================ */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 20px;
}
.section {
  padding: 72px 0;
}
.section-sm {
  padding: 48px 0;
}
.section-dark {
  background: var(--color-secondary);
  color: var(--color-white);
}
.section-gray {
  background: var(--color-bg2);
}

/* ---- 区块标题 ---- */
.section-header {
  text-align: center;
  margin-bottom: 48px;
}
.section-label {
  display: inline-block;
  background: rgba(255,107,43,0.1);
  color: var(--color-primary);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 4px 14px;
  border-radius: 20px;
  margin-bottom: 12px;
}
.section-title {
  font-size: 2rem;
  font-weight: 800;
  color: var(--color-secondary);
  line-height: 1.3;
  margin-bottom: 14px;
}
.section-dark .section-title { color: var(--color-white); }
.section-title em {
  color: var(--color-primary);
  font-style: normal;
}
.section-desc {
  font-size: 1rem;
  color: var(--color-text-light);
  max-width: 600px;
  margin: 0 auto;
}
.section-dark .section-desc { color: rgba(255,255,255,0.65); }

/* ============================================================
   Hero 首屏
   ============================================================ */
.hero {
  position: relative;
  min-height: 600px;
  display: flex;
  align-items: center;
  overflow: hidden;
  background: var(--color-secondary);
}
.hero-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  opacity: 0.45;
  z-index: 0;
}
.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(10,14,26,0.92) 0%, rgba(26,37,64,0.7) 60%, rgba(255,107,43,0.15) 100%);
  z-index: 1;
}
.hero-content {
  position: relative;
  z-index: 2;
  max-width: 1280px;
  margin: 0 auto;
  padding: 80px 20px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,107,43,0.18);
  border: 1px solid rgba(255,107,43,0.35);
  color: var(--color-primary);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  padding: 6px 16px;
  border-radius: 20px;
  margin-bottom: 20px;
}
.hero-badge::before {
  content: '';
  width: 6px;
  height: 6px;
  background: var(--color-primary);
  border-radius: 50%;
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0%,100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.4); }
}
.hero-title {
  font-size: 3rem;
  font-weight: 900;
  color: var(--color-white);
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}
.hero-title em {
  color: var(--color-primary);
  font-style: normal;
}
.hero-desc {
  font-size: 1.05rem;
  color: rgba(255,255,255,0.75);
  margin-bottom: 32px;
  line-height: 1.8;
}
.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}
.hero-stats {
  display: flex;
  gap: 32px;
  margin-top: 40px;
}
.hero-stat {
  text-align: center;
}
.hero-stat .num {
  font-size: 1.8rem;
  font-weight: 900;
  color: var(--color-primary);
  line-height: 1;
}
.hero-stat .label {
  font-size: 0.78rem;
  color: rgba(255,255,255,0.55);
  margin-top: 4px;
}
.hero-right {
  position: relative;
}
.hero-video-card {
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: var(--radius);
  overflow: hidden;
  backdrop-filter: blur(10px);
}
.hero-video-card img {
  width: 100%;
  aspect-ratio: 16/9;
  object-fit: cover;
}
.hero-video-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(10,14,26,0.3);
  transition: background var(--transition);
  cursor: pointer;
}
.hero-video-overlay:hover { background: rgba(10,14,26,0.15); }
.play-btn-lg {
  width: 72px;
  height: 72px;
  background: var(--color-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 0 0 12px rgba(255,107,43,0.2);
  transition: transform var(--transition), box-shadow var(--transition);
}
.play-btn-lg:hover {
  transform: scale(1.1);
  box-shadow: 0 0 0 18px rgba(255,107,43,0.15);
}
.play-btn-lg svg { margin-left: 4px; }

/* ============================================================
   按钮
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 8px;
  font-size: 0.92rem;
  font-weight: 700;
  cursor: pointer;
  border: 2px solid transparent;
  transition: all var(--transition);
  white-space: nowrap;
  text-decoration: none;
}
.btn-primary {
  background: var(--color-primary);
  color: var(--color-white);
  border-color: var(--color-primary);
}
.btn-primary:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(255,107,43,0.35);
}
.btn-outline {
  background: transparent;
  color: var(--color-white);
  border-color: rgba(255,255,255,0.4);
}
.btn-outline:hover {
  background: rgba(255,255,255,0.1);
  border-color: var(--color-white);
}
.btn-outline-dark {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}
.btn-outline-dark:hover {
  background: var(--color-primary);
  color: var(--color-white);
}
.btn-sm {
  padding: 8px 18px;
  font-size: 0.82rem;
}

/* ============================================================
   视频卡片
   ============================================================ */
.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}
.video-card {
  background: var(--color-white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
  cursor: pointer;
}
.video-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
}
.video-thumb {
  position: relative;
  aspect-ratio: 16/9;
  overflow: hidden;
  background: var(--color-secondary);
}
.video-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}
.video-card:hover .video-thumb img {
  transform: scale(1.06);
}
.video-play-overlay {
  position: absolute;
  inset: 0;
  background: rgba(10,14,26,0.35);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity var(--transition);
}
.video-card:hover .video-play-overlay {
  opacity: 1;
}
.play-btn {
  width: 52px;
  height: 52px;
  background: var(--color-primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 16px rgba(255,107,43,0.5);
  transform: scale(0.8);
  transition: transform var(--transition);
}
.video-card:hover .play-btn {
  transform: scale(1);
}
.play-btn svg { margin-left: 3px; }
.video-duration {
  position: absolute;
  bottom: 8px;
  right: 10px;
  background: rgba(10,14,26,0.75);
  color: var(--color-white);
  font-size: 0.72rem;
  font-weight: 600;
  padding: 2px 7px;
  border-radius: 4px;
}
.video-tag {
  position: absolute;
  top: 10px;
  left: 10px;
  background: var(--color-primary);
  color: var(--color-white);
  font-size: 0.68rem;
  font-weight: 700;
  padding: 3px 9px;
  border-radius: 4px;
  letter-spacing: 0.05em;
}
.video-info {
  padding: 16px;
}
.video-title {
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
  line-height: 1.45;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.video-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.76rem;
  color: var(--color-text-light);
}
.video-meta .views::before { content: '▶ '; }
.video-meta .likes::before { content: '♥ '; color: #e74c3c; }
.video-meta .comments::before { content: '💬 '; }
.video-author {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px solid var(--color-border);
}
.video-author-avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent2));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--color-white);
  flex-shrink: 0;
}
.video-author-name {
  font-size: 0.78rem;
  color: var(--color-text-light);
  font-weight: 600;
}

/* ============================================================
   专家卡片
   ============================================================ */
.expert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 28px;
}
.expert-card {
  background: var(--color-white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
  text-align: center;
}
.expert-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
}
.expert-cover {
  height: 180px;
  background: linear-gradient(135deg, var(--color-secondary), var(--color-accent2));
  position: relative;
  overflow: hidden;
}
.expert-cover img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.7;
}
.expert-avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary), #ff9a5c);
  border: 4px solid var(--color-white);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  font-weight: 900;
  color: var(--color-white);
  margin: -40px auto 0;
  position: relative;
  z-index: 1;
  box-shadow: 0 4px 16px rgba(255,107,43,0.3);
}
.expert-body {
  padding: 16px 20px 24px;
}
.expert-name {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--color-text);
  margin-bottom: 4px;
}
.expert-role {
  font-size: 0.78rem;
  color: var(--color-primary);
  font-weight: 600;
  margin-bottom: 12px;
}
.expert-desc {
  font-size: 0.82rem;
  color: var(--color-text-light);
  line-height: 1.6;
  margin-bottom: 14px;
}
.expert-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  justify-content: center;
  margin-bottom: 16px;
}
.expert-badge {
  background: var(--color-bg2);
  color: var(--color-text-light);
  font-size: 0.7rem;
  padding: 3px 10px;
  border-radius: 12px;
  font-weight: 600;
}
.expert-actions {
  display: flex;
  gap: 10px;
  justify-content: center;
}

/* ============================================================
   评价卡片
   ============================================================ */
.review-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
}
.review-card {
  background: var(--color-white);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
  border-left: 4px solid var(--color-primary);
  transition: transform var(--transition);
}
.review-card:hover { transform: translateY(-4px); }
.review-stars {
  color: var(--color-gold);
  font-size: 1rem;
  margin-bottom: 12px;
  letter-spacing: 2px;
}
.review-text {
  font-size: 0.9rem;
  color: var(--color-text);
  line-height: 1.7;
  margin-bottom: 16px;
}
.review-author {
  display: flex;
  align-items: center;
  gap: 12px;
}
.review-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent2));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--color-white);
  flex-shrink: 0;
}
.review-name {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--color-text);
}
.review-date {
  font-size: 0.75rem;
  color: var(--color-text-light);
}

/* ============================================================
   FAQ
   ============================================================ */
.faq-list {
  max-width: 860px;
  margin: 0 auto;
}
.faq-item {
  background: var(--color-white);
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
  box-shadow: 0 2px 10px rgba(10,14,26,0.06);
  overflow: hidden;
}
.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 22px;
  background: none;
  border: none;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--color-text);
  text-align: left;
  gap: 12px;
  transition: color var(--transition);
}
.faq-question:hover { color: var(--color-primary); }
.faq-icon {
  width: 24px;
  height: 24px;
  background: var(--color-bg2);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-primary);
  transition: transform var(--transition), background var(--transition);
}
.faq-item.active .faq-icon {
  transform: rotate(45deg);
  background: var(--color-primary);
  color: var(--color-white);
}
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding var(--transition);
  padding: 0 22px;
  font-size: 0.88rem;
  color: var(--color-text-light);
  line-height: 1.8;
}
.faq-item.active .faq-answer {
  max-height: 300px;
  padding: 0 22px 18px;
}

/* ============================================================
   合作品牌Logo墙
   ============================================================ */
.partner-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  justify-content: center;
  align-items: center;
}
.partner-item {
  background: var(--color-white);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 16px 28px;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--color-text-light);
  transition: all var(--transition);
  min-width: 120px;
  text-align: center;
}
.partner-item:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  transform: translateY(-3px);
  box-shadow: var(--shadow);
}

/* ============================================================
   联系区块
   ============================================================ */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: start;
}
.contact-info-list {
  display: flex;
  flex-direction: column;
  gap: 18px;
}
.contact-info-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
  padding: 18px;
  background: var(--color-bg2);
  border-radius: var(--radius-sm);
}
.contact-icon {
  width: 44px;
  height: 44px;
  background: var(--color-primary);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 1.2rem;
}
.contact-label {
  font-size: 0.78rem;
  color: var(--color-text-light);
  margin-bottom: 4px;
}
.contact-value {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--color-text);
}
.qr-group {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}
.qr-item {
  text-align: center;
}
.qr-code {
  width: 120px;
  height: 120px;
  background: var(--color-white);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 8px;
  overflow: hidden;
}
.qr-code canvas, .qr-code img { width: 100%; height: 100%; }
.qr-label {
  font-size: 0.78rem;
  color: var(--color-text-light);
  font-weight: 600;
}

/* ============================================================
   社区加入指南
   ============================================================ */
.howto-steps {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 24px;
  counter-reset: step;
}
.howto-step {
  background: var(--color-white);
  border-radius: var(--radius);
  padding: 28px 22px;
  text-align: center;
  box-shadow: var(--shadow);
  position: relative;
  transition: transform var(--transition);
}
.howto-step:hover { transform: translateY(-5px); }
.howto-step-num {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--color-primary), #ff9a5c);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  font-weight: 900;
  color: var(--color-white);
  margin: 0 auto 16px;
}
.howto-step-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
}
.howto-step-desc {
  font-size: 0.82rem;
  color: var(--color-text-light);
  line-height: 1.6;
}

/* ============================================================
   分享按钮
   ============================================================ */
.share-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}
.share-label {
  font-size: 0.85rem;
  color: var(--color-text-light);
  font-weight: 600;
}
.share-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border-radius: 6px;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
  color: var(--color-white);
}
.share-btn:hover { transform: translateY(-2px); opacity: 0.9; }
.share-wechat { background: #07c160; }
.share-weibo { background: #e6162d; }
.share-douyin { background: #010101; }
.share-bilibili { background: #00a1d6; }

/* ============================================================
   AI赋能区块
   ============================================================ */
.ai-features {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}
.ai-feature-card {
  background: var(--color-white);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
  border-top: 3px solid var(--color-primary);
  transition: transform var(--transition), box-shadow var(--transition);
}
.ai-feature-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}
.ai-feature-icon {
  font-size: 2.2rem;
  margin-bottom: 16px;
}
.ai-feature-title {
  font-size: 1rem;
  font-weight: 800;
  color: var(--color-text);
  margin-bottom: 10px;
}
.ai-feature-desc {
  font-size: 0.85rem;
  color: var(--color-text-light);
  line-height: 1.7;
}

/* ============================================================
   媒体模块
   ============================================================ */
.media-tabs {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 32px;
}
.media-tab {
  padding: 8px 20px;
  border-radius: 24px;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  border: 1.5px solid var(--color-border);
  background: var(--color-white);
  color: var(--color-text-light);
  transition: all var(--transition);
}
.media-tab:hover,
.media-tab.active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-white);
}

/* ============================================================
   页脚
   ============================================================ */
.site-footer {
  background: var(--color-secondary);
  color: rgba(255,255,255,0.7);
  padding: 60px 0 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}
.footer-brand .logo-text {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--color-white);
  margin-bottom: 12px;
}
.footer-brand .logo-text span { color: var(--color-primary); }
.footer-brand p {
  font-size: 0.85rem;
  line-height: 1.8;
  margin-bottom: 20px;
}
.footer-col-title {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 16px;
}
.footer-links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.footer-links a {
  font-size: 0.83rem;
  color: rgba(255,255,255,0.6);
  transition: color var(--transition);
}
.footer-links a:hover { color: var(--color-primary); }
.footer-bottom {
  padding: 20px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 0.8rem;
  color: rgba(255,255,255,0.45);
}
.footer-bottom a { color: rgba(255,255,255,0.6); }
.footer-bottom a:hover { color: var(--color-primary); }
.footer-update {
  font-size: 0.78rem;
  color: rgba(255,255,255,0.4);
}

/* ============================================================
   内页Banner
   ============================================================ */
.page-banner {
  background: linear-gradient(135deg, var(--color-secondary) 0%, var(--color-accent2) 100%);
  padding: 60px 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.page-banner::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -10%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(255,107,43,0.15) 0%, transparent 70%);
  pointer-events: none;
}
.page-banner h1 {
  font-size: 2.2rem;
  font-weight: 900;
  color: var(--color-white);
  margin-bottom: 12px;
}
.page-banner h1 em { color: var(--color-primary); font-style: normal; }
.page-banner p {
  font-size: 1rem;
  color: rgba(255,255,255,0.7);
  max-width: 600px;
  margin: 0 auto;
}

/* ============================================================
   通用卡片
   ============================================================ */
.card {
  background: var(--color-white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  transition: transform var(--transition), box-shadow var(--transition);
}
.card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}
.card-img {
  width: 100%;
  aspect-ratio: 16/9;
  object-fit: cover;
}
.card-body {
  padding: 20px;
}
.card-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
}
.card-text {
  font-size: 0.85rem;
  color: var(--color-text-light);
  line-height: 1.7;
}
.card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--color-border);
  font-size: 0.78rem;
  color: var(--color-text-light);
}

/* ============================================================
   标签
   ============================================================ */
.tag {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 4px;
  font-size: 0.72rem;
  font-weight: 600;
}
.tag-primary { background: rgba(255,107,43,0.1); color: var(--color-primary); }
.tag-dark { background: var(--color-secondary); color: var(--color-white); }
.tag-gray { background: var(--color-bg2); color: var(--color-text-light); }

/* ============================================================
   滚动条
   ============================================================ */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--color-bg2); }
::-webkit-scrollbar-thumb { background: var(--color-border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--color-primary); }

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

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 1024px) {
  .hero-content { grid-template-columns: 1fr; gap: 40px; }
  .hero-right { display: none; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
  .main-nav { display: none; }
  .main-nav.open { display: flex; flex-direction: column; position: fixed; top: 70px; left: 0; right: 0; background: var(--color-white); padding: 20px; box-shadow: var(--shadow-lg); z-index: 999; }
  .main-nav.open ul { flex-direction: column; width: 100%; }
  .main-nav.open ul li a { padding: 12px 16px; border-radius: var(--radius-sm); }
  .nav-toggle { display: flex; }
  .header-search input { width: 150px; }
  .hero-title { font-size: 2rem; }
  .section-title { font-size: 1.6rem; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; text-align: center; }
  .video-grid { grid-template-columns: 1fr 1fr; }
  .expert-grid { grid-template-columns: 1fr 1fr; }
  .review-grid { grid-template-columns: 1fr; }
  .howto-steps { grid-template-columns: 1fr 1fr; }
  .hero-stats { gap: 20px; }
}
@media (max-width: 480px) {
  .video-grid { grid-template-columns: 1fr; }
  .expert-grid { grid-template-columns: 1fr; }
  .howto-steps { grid-template-columns: 1fr; }
  .hero-actions { flex-direction: column; }
  .header-search { display: none; }
  .site-topbar .topbar-inner { flex-direction: column; gap: 4px; }
}

/* ============================================================
   科普教育模块 (edu-grid / edu-card)
   ============================================================ */
.edu-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-top: 40px;
}
.edu-card {
  background: var(--color-white);
  border-radius: var(--radius);
  padding: 28px 22px;
  box-shadow: var(--shadow);
  border: 1px solid var(--color-border);
  transition: transform var(--transition), box-shadow var(--transition);
}
.edu-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}
.edu-icon {
  font-size: 2rem;
  margin-bottom: 14px;
}
.edu-card-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-secondary);
  margin-bottom: 8px;
}
.edu-sub {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--color-primary);
  margin-bottom: 10px;
}
.edu-sub2 {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--color-text-light);
  margin: 12px 0 6px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.edu-sub3 {
  font-size: 0.76rem;
  font-weight: 600;
  color: var(--color-accent2);
  margin: 12px 0 6px;
}
.edu-card p {
  font-size: 0.85rem;
  color: var(--color-text-light);
  line-height: 1.65;
  margin-bottom: 10px;
}
.edu-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.edu-list li {
  font-size: 0.82rem;
  padding: 4px 0;
  border-bottom: 1px dashed var(--color-border);
}
.edu-list li:last-child { border-bottom: none; }
.edu-list a {
  color: var(--color-primary);
  transition: color var(--transition);
}
.edu-list a:hover { color: var(--color-primary-dark); }

@media (max-width: 1024px) {
  .edu-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 600px) {
  .edu-grid { grid-template-columns: 1fr; }
}