/* =============================================
   糖心vlog网 - 主样式文件
   品牌色：深海蓝 #1a3a5c | 珊瑚红 #e05c4b | 金色 #d4a843
   ============================================= */

:root {
  --primary: #1a3a5c;
  --secondary: #e05c4b;
  --accent: #d4a843;
  --dark: #0d1f33;
  --light: #f4f8fc;
  --gray: #6b7a8d;
  --white: #ffffff;
  --border: #dde4ed;
  --shadow: 0 4px 20px rgba(26,58,92,0.12);
  --radius: 10px;
  --transition: all 0.3s ease;
}

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

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

body {
  font-family: 'PingFang SC', 'Microsoft YaHei', '微软雅黑', sans-serif;
  color: #2c3e50;
  background: var(--white);
  line-height: 1.7;
  overflow-x: hidden;
}

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

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

/* ========== 顶部公告栏 ========== */
.top-bar {
  background: var(--primary);
  color: rgba(255,255,255,0.85);
  font-size: 13px;
  padding: 6px 0;
  text-align: center;
}
.top-bar a { color: var(--accent); }

/* ========== 头部导航 ========== */
.site-header {
  background: var(--white);
  box-shadow: 0 2px 12px rgba(26,58,92,0.08);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 0;
  gap: 20px;
}

.logo-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.logo-icon {
  width: 44px;
  height: 44px;
  object-fit: contain;
  border-radius: 8px;
}

.logo-text {
  display: flex;
  flex-direction: column;
}

.logo-name {
  font-size: 22px;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: 2px;
  line-height: 1.2;
}

.logo-slogan {
  font-size: 11px;
  color: var(--gray);
  letter-spacing: 1px;
}

/* 主导航 */
.main-nav { display: flex; align-items: center; gap: 4px; }

.main-nav a {
  padding: 8px 14px;
  font-size: 14px;
  font-weight: 500;
  color: var(--primary);
  border-radius: 6px;
  white-space: nowrap;
}

.main-nav a:hover,
.main-nav a.active {
  background: var(--light);
  color: var(--secondary);
}

/* 搜索框 */
.search-wrap {
  display: flex;
  align-items: center;
  background: var(--light);
  border: 1.5px solid var(--border);
  border-radius: 24px;
  padding: 6px 14px;
  gap: 8px;
  min-width: 200px;
  transition: var(--transition);
}

.search-wrap:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(26,58,92,0.1);
}

.search-wrap input {
  border: none;
  background: transparent;
  font-size: 14px;
  color: var(--primary);
  outline: none;
  width: 100%;
}

.search-wrap input::placeholder { color: var(--gray); }

.search-btn {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--gray);
  font-size: 16px;
  padding: 0;
  transition: var(--transition);
}

.search-btn:hover { color: var(--secondary); }

/* 汉堡菜单 */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
}

.hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--primary);
  border-radius: 2px;
  transition: var(--transition);
}

/* ========== Hero 横幅 ========== */
.hero-section {
  position: relative;
  height: 560px;
  overflow: hidden;
  background: var(--dark);
}

.hero-bg {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.75;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(13,31,51,0.85) 0%, rgba(26,58,92,0.5) 60%, transparent 100%);
  display: flex;
  align-items: center;
}

.hero-content {
  padding: 0 60px;
  max-width: 700px;
}

.hero-tag {
  display: inline-block;
  background: var(--secondary);
  color: var(--white);
  font-size: 12px;
  padding: 4px 12px;
  border-radius: 20px;
  margin-bottom: 16px;
  letter-spacing: 1px;
}

.hero-content h1 {
  font-size: 48px;
  font-weight: 900;
  color: var(--white);
  line-height: 1.2;
  margin-bottom: 16px;
  text-shadow: 0 2px 8px rgba(0,0,0,0.3);
}

.hero-content h1 span { color: var(--accent); }

.hero-desc {
  font-size: 17px;
  color: rgba(255,255,255,0.85);
  margin-bottom: 28px;
  line-height: 1.8;
}

.hero-btns { display: flex; gap: 14px; flex-wrap: wrap; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  border: 2px solid transparent;
  transition: var(--transition);
}

.btn-primary {
  background: var(--secondary);
  color: var(--white);
  border-color: var(--secondary);
}

.btn-primary:hover {
  background: #c94a39;
  border-color: #c94a39;
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(224,92,75,0.4);
}

.btn-outline {
  background: transparent;
  color: var(--white);
  border-color: rgba(255,255,255,0.6);
}

.btn-outline:hover {
  background: rgba(255,255,255,0.15);
  border-color: var(--white);
}

/* ========== 通用区块样式 ========== */
.section { padding: 70px 0; }
.section-alt { background: var(--light); }

.section-header {
  text-align: center;
  margin-bottom: 48px;
}

.section-tag {
  display: inline-block;
  background: rgba(224,92,75,0.1);
  color: var(--secondary);
  font-size: 12px;
  font-weight: 600;
  padding: 4px 14px;
  border-radius: 20px;
  margin-bottom: 12px;
  letter-spacing: 1px;
}

.section-header h2 {
  font-size: 32px;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 12px;
}

.section-header p {
  font-size: 16px;
  color: var(--gray);
  max-width: 600px;
  margin: 0 auto;
}

/* ========== 视频卡片 ========== */
.video-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.video-card {
  background: var(--white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
  cursor: pointer;
}

.video-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 40px rgba(26,58,92,0.18);
}

.video-thumb {
  position: relative;
  aspect-ratio: 16/9;
  overflow: hidden;
  background: var(--dark);
}

.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-btn {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.3);
  opacity: 0;
  transition: var(--transition);
}

.video-card:hover .play-btn { opacity: 1; }

.play-icon {
  width: 52px;
  height: 52px;
  background: rgba(255,255,255,0.92);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transform: scale(0.85);
  transition: var(--transition);
}

.video-card:hover .play-icon { transform: scale(1); }

.play-icon::after {
  content: '';
  border-left: 18px solid var(--secondary);
  border-top: 11px solid transparent;
  border-bottom: 11px solid transparent;
  margin-left: 4px;
}

.video-badge {
  position: absolute;
  top: 10px;
  left: 10px;
  background: var(--secondary);
  color: var(--white);
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 4px;
}

.video-duration {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(0,0,0,0.7);
  color: var(--white);
  font-size: 12px;
  padding: 2px 6px;
  border-radius: 4px;
}

.video-info { padding: 14px; }

.video-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--primary);
  margin-bottom: 8px;
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.video-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 12px;
  color: var(--gray);
}

.video-meta span { display: flex; align-items: center; gap: 4px; }

/* ========== 图文卡片 ========== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.card {
  background: var(--white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 32px rgba(26,58,92,0.16);
}

.card-img {
  aspect-ratio: 4/3;
  overflow: hidden;
}

.card-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}

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

.card-body { padding: 18px; }

.card-tag {
  display: inline-block;
  background: rgba(26,58,92,0.08);
  color: var(--primary);
  font-size: 11px;
  padding: 3px 10px;
  border-radius: 4px;
  margin-bottom: 10px;
}

.card-title {
  font-size: 16px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 8px;
  line-height: 1.5;
}

.card-desc {
  font-size: 13px;
  color: var(--gray);
  line-height: 1.7;
  margin-bottom: 14px;
}

.card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 12px;
  color: var(--gray);
  border-top: 1px solid var(--border);
  padding-top: 12px;
}

/* ========== 功能模块区 ========== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.feature-item {
  text-align: center;
  padding: 28px 20px;
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: var(--transition);
  border-bottom: 3px solid transparent;
}

.feature-item:hover {
  border-bottom-color: var(--secondary);
  transform: translateY(-4px);
}

.feature-icon {
  width: 60px;
  height: 60px;
  background: linear-gradient(135deg, var(--primary), #2a5a8c);
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  font-size: 26px;
  color: var(--white);
}

.feature-item h3 {
  font-size: 16px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 8px;
}

.feature-item p {
  font-size: 13px;
  color: var(--gray);
  line-height: 1.6;
}

/* ========== 专家展示 ========== */
.expert-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.expert-card {
  background: var(--white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  text-align: center;
  transition: var(--transition);
}

.expert-card:hover { transform: translateY(-6px); box-shadow: 0 14px 40px rgba(26,58,92,0.18); }

.expert-avatar {
  width: 100%;
  aspect-ratio: 1;
  object-fit: cover;
}

.expert-info { padding: 18px; }

.expert-name {
  font-size: 17px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 4px;
}

.expert-role {
  font-size: 13px;
  color: var(--secondary);
  margin-bottom: 10px;
}

.expert-desc {
  font-size: 13px;
  color: var(--gray);
  line-height: 1.6;
  margin-bottom: 14px;
}

.expert-tags { display: flex; flex-wrap: wrap; gap: 6px; justify-content: center; margin-bottom: 14px; }

.tag {
  background: var(--light);
  color: var(--primary);
  font-size: 11px;
  padding: 3px 10px;
  border-radius: 20px;
  border: 1px solid var(--border);
}

.expert-btns { display: flex; gap: 8px; justify-content: center; }

.btn-sm {
  padding: 7px 16px;
  font-size: 13px;
  border-radius: 6px;
  font-weight: 600;
  cursor: pointer;
  border: 1.5px solid;
  transition: var(--transition);
}

.btn-sm-primary {
  background: var(--primary);
  color: var(--white);
  border-color: var(--primary);
}

.btn-sm-primary:hover { background: #0d2640; }

.btn-sm-outline {
  background: transparent;
  color: var(--primary);
  border-color: var(--primary);
}

.btn-sm-outline:hover { background: var(--light); }

/* ========== 统计数据 ========== */
.stats-section {
  background: linear-gradient(135deg, var(--primary) 0%, #2a5a8c 100%);
  padding: 60px 0;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  text-align: center;
}

.stat-item { color: var(--white); }

.stat-num {
  font-size: 44px;
  font-weight: 900;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 8px;
}

.stat-label {
  font-size: 15px;
  color: rgba(255,255,255,0.8);
}

/* ========== FAQ ========== */
.faq-list { max-width: 800px; margin: 0 auto; }

.faq-item {
  background: var(--white);
  border-radius: var(--radius);
  margin-bottom: 12px;
  box-shadow: 0 2px 10px rgba(26,58,92,0.07);
  overflow: hidden;
}

.faq-q {
  padding: 18px 22px;
  font-size: 15px;
  font-weight: 600;
  color: var(--primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
}

.faq-q::after {
  content: '+';
  font-size: 22px;
  color: var(--secondary);
  font-weight: 400;
  transition: var(--transition);
  flex-shrink: 0;
}

.faq-item.open .faq-q::after { content: '−'; }

.faq-a {
  padding: 0 22px;
  font-size: 14px;
  color: var(--gray);
  line-height: 1.8;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
}

.faq-item.open .faq-a {
  max-height: 300px;
  padding: 0 22px 18px;
}

/* ========== 用户评价 ========== */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.review-card {
  background: var(--white);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
  border-top: 3px solid var(--secondary);
}

.review-stars { color: var(--accent); font-size: 16px; margin-bottom: 12px; }

.review-text {
  font-size: 14px;
  color: #444;
  line-height: 1.8;
  margin-bottom: 16px;
  font-style: italic;
}

.review-user { display: flex; align-items: center; gap: 10px; }

.review-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-size: 16px;
  font-weight: 700;
  flex-shrink: 0;
}

.review-name { font-size: 14px; font-weight: 600; color: var(--primary); }
.review-date { font-size: 12px; color: var(--gray); }

/* ========== 合作品牌 ========== */
.partners-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 40px;
  flex-wrap: wrap;
}

.partner-item {
  background: var(--white);
  border: 1.5px solid var(--border);
  border-radius: 8px;
  padding: 14px 28px;
  font-size: 16px;
  font-weight: 700;
  color: var(--gray);
  transition: var(--transition);
}

.partner-item:hover {
  border-color: var(--primary);
  color: var(--primary);
  box-shadow: var(--shadow);
}

/* ========== 联系我们 ========== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: start;
}

.contact-info h3 {
  font-size: 22px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 20px;
}

.contact-item {
  display: flex;
  gap: 14px;
  margin-bottom: 18px;
  align-items: flex-start;
}

.contact-icon {
  width: 44px;
  height: 44px;
  background: var(--light);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  flex-shrink: 0;
}

.contact-text strong { display: block; font-size: 14px; color: var(--primary); margin-bottom: 2px; }
.contact-text span { font-size: 13px; color: var(--gray); }

.qr-row { display: flex; gap: 24px; margin-top: 24px; }

.qr-item { text-align: center; }

.qr-item img {
  width: 120px;
  height: 120px;
  object-fit: cover;
  border-radius: 8px;
  border: 2px solid var(--border);
}

.qr-item p { font-size: 12px; color: var(--gray); margin-top: 8px; }

/* ========== 社交分享 ========== */
.share-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.share-label { font-size: 14px; color: var(--gray); }

.share-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border-radius: 6px;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  color: var(--white);
}

.share-wechat { background: #07c160; }
.share-weibo { background: #e6162d; }
.share-douyin { background: #010101; }
.share-bilibili { background: #00a1d6; }

.share-btn:hover { opacity: 0.88; transform: translateY(-2px); }

/* ========== 底部 ========== */
.site-footer {
  background: var(--dark);
  color: rgba(255,255,255,0.75);
  padding: 60px 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand .logo-name { color: var(--white); }
.footer-brand .logo-slogan { color: rgba(255,255,255,0.5); }

.footer-desc {
  font-size: 13px;
  color: rgba(255,255,255,0.6);
  line-height: 1.8;
  margin: 16px 0;
}

.footer-col h4 {
  font-size: 15px;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--secondary);
  display: inline-block;
}

.footer-col ul li { margin-bottom: 10px; }

.footer-col ul li a {
  font-size: 13px;
  color: rgba(255,255,255,0.6);
  transition: var(--transition);
}

.footer-col ul li a:hover { color: var(--accent); padding-left: 4px; }

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding: 20px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 13px;
  color: rgba(255,255,255,0.45);
  flex-wrap: wrap;
  gap: 10px;
}

.footer-bottom a { color: rgba(255,255,255,0.6); }
.footer-bottom a:hover { color: var(--accent); }

/* ========== 面包屑 ========== */
.breadcrumb {
  background: var(--light);
  padding: 12px 0;
  font-size: 13px;
  color: var(--gray);
}

.breadcrumb a { color: var(--primary); }
.breadcrumb a:hover { color: var(--secondary); }
.breadcrumb span { margin: 0 6px; }

/* ========== 内页 Banner ========== */
.page-banner {
  background: linear-gradient(135deg, var(--primary) 0%, #2a5a8c 100%);
  padding: 60px 0;
  text-align: center;
  color: var(--white);
}

.page-banner h1 {
  font-size: 38px;
  font-weight: 800;
  margin-bottom: 12px;
}

.page-banner p {
  font-size: 16px;
  color: rgba(255,255,255,0.8);
}

/* ========== 直播区域 ========== */
.live-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.live-card {
  background: var(--white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.live-card:hover { transform: translateY(-4px); }

.live-thumb {
  position: relative;
  aspect-ratio: 4/3;
  overflow: hidden;
}

.live-thumb img { width: 100%; height: 100%; object-fit: cover; }

.live-badge {
  position: absolute;
  top: 10px;
  left: 10px;
  background: #ff4444;
  color: var(--white);
  font-size: 11px;
  padding: 3px 10px;
  border-radius: 4px;
  font-weight: 700;
  animation: pulse 1.5s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

.live-viewers {
  position: absolute;
  bottom: 8px;
  right: 8px;
  background: rgba(0,0,0,0.65);
  color: var(--white);
  font-size: 12px;
  padding: 3px 8px;
  border-radius: 4px;
}

.live-info { padding: 14px; }
.live-title { font-size: 14px; font-weight: 600; color: var(--primary); margin-bottom: 6px; }
.live-host { font-size: 13px; color: var(--gray); }

/* ========== AI赋能区 ========== */
.ai-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.ai-card {
  background: linear-gradient(135deg, var(--primary) 0%, #1e4a7a 100%);
  border-radius: var(--radius);
  padding: 28px;
  color: var(--white);
  transition: var(--transition);
}

.ai-card:hover { transform: translateY(-4px); box-shadow: 0 12px 36px rgba(26,58,92,0.3); }

.ai-icon { font-size: 36px; margin-bottom: 14px; }

.ai-card h3 { font-size: 18px; font-weight: 700; margin-bottom: 10px; color: var(--accent); }

.ai-card p { font-size: 14px; color: rgba(255,255,255,0.8); line-height: 1.7; }

/* ========== 加入社区 How-To ========== */
.howto-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
  position: relative;
}

.howto-steps::before {
  content: '';
  position: absolute;
  top: 36px;
  left: 10%;
  right: 10%;
  height: 2px;
  background: linear-gradient(90deg, var(--secondary), var(--accent));
}

.step-item {
  text-align: center;
  position: relative;
  z-index: 1;
}

.step-num {
  width: 72px;
  height: 72px;
  background: var(--white);
  border: 3px solid var(--secondary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  font-weight: 900;
  color: var(--secondary);
  margin: 0 auto 16px;
  box-shadow: var(--shadow);
}

.step-item h4 { font-size: 15px; font-weight: 700; color: var(--primary); margin-bottom: 8px; }
.step-item p { font-size: 13px; color: var(--gray); line-height: 1.6; }

/* ========== 响应式 ========== */
@media (max-width: 1024px) {
  .video-grid { grid-template-columns: repeat(2, 1fr); }
  .expert-grid { grid-template-columns: repeat(2, 1fr); }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .howto-steps::before { display: none; }
  .howto-steps { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .header-inner { flex-wrap: wrap; }
  .main-nav { display: none; width: 100%; flex-direction: column; gap: 0; }
  .main-nav.open { display: flex; }
  .main-nav a { padding: 12px 16px; border-bottom: 1px solid var(--border); border-radius: 0; }
  .hamburger { display: flex; }
  .search-wrap { min-width: 140px; }
  .hero-section { height: 420px; }
  .hero-content { padding: 0 24px; }
  .hero-content h1 { font-size: 32px; }
  .card-grid { grid-template-columns: 1fr; }
  .live-grid { grid-template-columns: 1fr; }
  .ai-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .reviews-grid { grid-template-columns: 1fr 1fr; }
  .section { padding: 48px 0; }
  .section-header h2 { font-size: 26px; }
}

@media (max-width: 480px) {
  .video-grid { grid-template-columns: 1fr; }
  .expert-grid { grid-template-columns: 1fr; }
  .feature-grid { grid-template-columns: 1fr 1fr; }
  .stats-grid { grid-template-columns: 1fr 1fr; }
  .reviews-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .howto-steps { grid-template-columns: 1fr; }
  .hero-content h1 { font-size: 26px; }
}

/* ========== 懒加载占位 ========== */
img[data-src] {
  background: linear-gradient(90deg, #f0f4f8 25%, #e0e8f0 50%, #f0f4f8 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ========== 滚动条美化 ========== */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--light); }
::-webkit-scrollbar-thumb { background: var(--primary); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--secondary); }

/* ========== 回到顶部 ========== */
.back-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 44px;
  height: 44px;
  background: var(--primary);
  color: var(--white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  cursor: pointer;
  box-shadow: 0 4px 16px rgba(26,58,92,0.3);
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
  z-index: 999;
  border: none;
}

.back-top.show { opacity: 1; visibility: visible; }
.back-top:hover { background: var(--secondary); transform: translateY(-3px); }

/* ========== 内页侧边栏 ========== */
.page-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 32px;
  padding: 48px 0;
}

.sidebar-widget {
  background: var(--white);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
  margin-bottom: 24px;
}

.sidebar-widget h4 {
  font-size: 15px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 16px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--secondary);
}

.hot-list li {
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
  font-size: 13px;
}

.hot-list li:last-child { border-bottom: none; }

.hot-list a { color: var(--primary); }
.hot-list a:hover { color: var(--secondary); }

@media (max-width: 900px) {
  .page-layout { grid-template-columns: 1fr; }
}