/* ============================================================
   Telegram 官网模板 - 主样式文件
   符合谷歌SEO / GEO 标准
   ============================================================ */

/* ---- CSS 变量 ---- */
:root {
  --tg-blue: #2AABEE;
  --tg-dark-blue: #1a8cc7;
  --tg-deeper-blue: #0d6fa8;
  --tg-bg: #ffffff;
  --tg-bg-light: #f4f9fd;
  --tg-bg-section: #eef6fc;
  --tg-text: #222222;
  --tg-text-muted: #666666;
  --tg-text-light: #999999;
  --tg-border: #e0eaf3;
  --tg-radius: 12px;
  --tg-radius-sm: 8px;
  --tg-shadow: 0 4px 24px rgba(42,171,238,0.10);
  --tg-shadow-hover: 0 8px 32px rgba(42,171,238,0.18);
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

/* ---- 重置 & 基础 ---- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font-main);
  color: var(--tg-text);
  background: var(--tg-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--tg-blue); text-decoration: none; transition: color .2s; }
a:hover { color: var(--tg-dark-blue); text-decoration: underline; }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }

/* ---- 容器 ---- */
.container { max-width: 1160px; margin: 0 auto; padding: 0 24px; }
.container-sm { max-width: 860px; margin: 0 auto; padding: 0 24px; }

/* ============================================================
   顶部导航
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: #fff;
  border-bottom: 1px solid var(--tg-border);
  box-shadow: 0 2px 12px rgba(42,171,238,0.07);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.site-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--tg-text);
}
.site-logo img {
  width: 40px;
  height: 40px;
  border-radius: 50%;
}
.site-logo span { color: var(--tg-blue); }

/* 主导航 */
.main-nav { display: flex; align-items: center; gap: 4px; }
.main-nav a {
  padding: 8px 14px;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--tg-text);
  transition: background .2s, color .2s;
}
.main-nav a:hover,
.main-nav a.active {
  background: var(--tg-bg-section);
  color: var(--tg-blue);
  text-decoration: none;
}

/* 右侧操作区 */
.header-actions { display: flex; align-items: center; gap: 12px; }
.btn-download {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--tg-blue);
  color: #fff !important;
  padding: 9px 20px;
  border-radius: 24px;
  font-size: 0.9rem;
  font-weight: 600;
  transition: background .2s, transform .15s;
  text-decoration: none !important;
}
.btn-download:hover { background: var(--tg-dark-blue); transform: translateY(-1px); }

/* 汉堡菜单 */
.menu-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 4px; }
.menu-toggle span { display: block; width: 24px; height: 2px; background: var(--tg-text); border-radius: 2px; transition: all .3s; }

/* ============================================================
   面包屑
   ============================================================ */
.breadcrumb {
  background: var(--tg-bg-light);
  border-bottom: 1px solid var(--tg-border);
  padding: 10px 0;
  font-size: 0.875rem;
}
.breadcrumb ol { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; }
.breadcrumb li { display: flex; align-items: center; gap: 6px; color: var(--tg-text-muted); }
.breadcrumb li + li::before { content: "›"; color: var(--tg-text-light); }
.breadcrumb a { color: var(--tg-blue); }
.breadcrumb a:hover { text-decoration: underline; }
.breadcrumb li:last-child { color: var(--tg-text); font-weight: 500; }

/* ============================================================
   Hero / 轮播区
   ============================================================ */
.hero-section {
  background: linear-gradient(135deg, #e8f6fd 0%, #d0ecf9 40%, #b8e2f5 100%);
  padding: 80px 0 60px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.hero-section::before {
  content: '';
  position: absolute;
  top: -60px; right: -60px;
  width: 300px; height: 300px;
  background: radial-gradient(circle, rgba(42,171,238,0.15) 0%, transparent 70%);
  border-radius: 50%;
}
.hero-section::after {
  content: '';
  position: absolute;
  bottom: -40px; left: -40px;
  width: 200px; height: 200px;
  background: radial-gradient(circle, rgba(42,171,238,0.10) 0%, transparent 70%);
  border-radius: 50%;
}
.hero-logo {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  margin: 0 auto 24px;
  box-shadow: 0 8px 32px rgba(42,171,238,0.25);
}
.hero-title {
  font-size: 2.8rem;
  font-weight: 800;
  color: var(--tg-text);
  margin-bottom: 16px;
  line-height: 1.2;
}
.hero-title .brand { color: var(--tg-blue); }
.hero-subtitle {
  font-size: 1.2rem;
  color: var(--tg-text-muted);
  max-width: 600px;
  margin: 0 auto 36px;
}
.hero-actions { display: flex; justify-content: center; gap: 16px; flex-wrap: wrap; }
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--tg-blue);
  color: #fff;
  padding: 14px 32px;
  border-radius: 32px;
  font-size: 1rem;
  font-weight: 700;
  text-decoration: none;
  transition: background .2s, transform .15s, box-shadow .2s;
  box-shadow: 0 4px 16px rgba(42,171,238,0.3);
}
.btn-primary:hover { background: var(--tg-dark-blue); transform: translateY(-2px); box-shadow: 0 8px 24px rgba(42,171,238,0.4); color: #fff; text-decoration: none; }
.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: #fff;
  color: var(--tg-blue);
  padding: 14px 32px;
  border-radius: 32px;
  font-size: 1rem;
  font-weight: 700;
  text-decoration: none;
  border: 2px solid var(--tg-blue);
  transition: all .2s;
}
.btn-secondary:hover { background: var(--tg-bg-section); transform: translateY(-2px); text-decoration: none; }

/* 轮播 */
.carousel-section { background: #fff; padding: 48px 0; }
.carousel-wrapper { position: relative; overflow: hidden; border-radius: var(--tg-radius); }
.carousel-track { display: flex; transition: transform .5s ease; }
.carousel-slide {
  min-width: 100%;
  position: relative;
  border-radius: var(--tg-radius);
  overflow: hidden;
}
.carousel-slide img { width: 100%; height: 420px; object-fit: cover; }
.carousel-caption {
  position: absolute;
  bottom: 0; left: 0; right: 0;
  background: linear-gradient(transparent, rgba(0,0,0,0.6));
  color: #fff;
  padding: 32px 32px 24px;
}
.carousel-caption h3 { font-size: 1.4rem; font-weight: 700; margin-bottom: 8px; }
.carousel-caption p { font-size: 0.95rem; opacity: 0.9; }
.carousel-controls { display: flex; justify-content: center; gap: 8px; margin-top: 16px; }
.carousel-dot {
  width: 10px; height: 10px;
  border-radius: 50%;
  background: var(--tg-border);
  cursor: pointer;
  transition: background .2s, transform .2s;
  border: none;
}
.carousel-dot.active { background: var(--tg-blue); transform: scale(1.3); }
.carousel-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(255,255,255,0.9);
  border: none;
  width: 44px; height: 44px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.2rem;
  color: var(--tg-blue);
  box-shadow: 0 2px 12px rgba(0,0,0,0.15);
  transition: background .2s;
  z-index: 10;
  display: flex; align-items: center; justify-content: center;
}
.carousel-btn:hover { background: #fff; }
.carousel-btn.prev { left: 16px; }
.carousel-btn.next { right: 16px; }

/* ============================================================
   特性卡片
   ============================================================ */
.features-section { padding: 72px 0; background: var(--tg-bg-light); }
.section-header { text-align: center; margin-bottom: 48px; }
.section-title {
  font-size: 2rem;
  font-weight: 800;
  color: var(--tg-text);
  margin-bottom: 12px;
}
.section-title .brand { color: var(--tg-blue); }
.section-desc { font-size: 1.05rem; color: var(--tg-text-muted); max-width: 560px; margin: 0 auto; }

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.feature-card {
  background: #fff;
  border-radius: var(--tg-radius);
  padding: 32px 24px;
  text-align: center;
  box-shadow: var(--tg-shadow);
  transition: transform .25s, box-shadow .25s;
  border: 1px solid var(--tg-border);
}
.feature-card:hover { transform: translateY(-6px); box-shadow: var(--tg-shadow-hover); }
.feature-icon {
  width: 64px; height: 64px;
  background: var(--tg-bg-section);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 16px;
  font-size: 1.8rem;
}
.feature-card h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 10px; color: var(--tg-text); }
.feature-card p { font-size: 0.9rem; color: var(--tg-text-muted); line-height: 1.6; }

/* ============================================================
   下载区域
   ============================================================ */
.download-section { padding: 72px 0; background: #fff; }
.download-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  margin-top: 40px;
}
.download-card {
  display: flex;
  align-items: center;
  gap: 20px;
  background: var(--tg-bg-light);
  border: 1px solid var(--tg-border);
  border-radius: var(--tg-radius);
  padding: 28px 24px;
  transition: all .25s;
  text-decoration: none;
  color: var(--tg-text);
}
.download-card:hover {
  border-color: var(--tg-blue);
  background: var(--tg-bg-section);
  transform: translateY(-4px);
  box-shadow: var(--tg-shadow-hover);
  text-decoration: none;
  color: var(--tg-text);
}
.download-card-icon {
  width: 56px; height: 56px;
  background: var(--tg-blue);
  border-radius: 14px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.6rem;
  flex-shrink: 0;
  color: #fff;
}
.download-card-info h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 4px; }
.download-card-info p { font-size: 0.875rem; color: var(--tg-text-muted); }
.download-card-arrow { margin-left: auto; color: var(--tg-blue); font-size: 1.2rem; }

/* ============================================================
   新闻/文章列表
   ============================================================ */
.news-section { padding: 72px 0; background: var(--tg-bg-light); }
.news-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 40px;
}
.news-card {
  background: #fff;
  border-radius: var(--tg-radius);
  overflow: hidden;
  box-shadow: var(--tg-shadow);
  border: 1px solid var(--tg-border);
  transition: transform .25s, box-shadow .25s;
  display: flex;
  flex-direction: column;
}
.news-card:hover { transform: translateY(-5px); box-shadow: var(--tg-shadow-hover); }
.news-card-thumb {
  width: 100%;
  height: 180px;
  object-fit: cover;
}
.news-card-thumb-placeholder {
  width: 100%;
  height: 180px;
  background: linear-gradient(135deg, var(--tg-bg-section), #c8e8f8);
  display: flex; align-items: center; justify-content: center;
  font-size: 2.5rem;
}
.news-card-body { padding: 20px; flex: 1; display: flex; flex-direction: column; }
.news-card-meta { display: flex; align-items: center; gap: 8px; margin-bottom: 10px; }
.news-card-cat {
  background: var(--tg-bg-section);
  color: var(--tg-blue);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 20px;
}
.news-card-date { font-size: 0.8rem; color: var(--tg-text-light); }
.news-card-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--tg-text);
  margin-bottom: 10px;
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.news-card-title a { color: var(--tg-text); text-decoration: none; }
.news-card-title a:hover { color: var(--tg-blue); }
.news-card-excerpt { font-size: 0.875rem; color: var(--tg-text-muted); line-height: 1.6; flex: 1; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.news-card-footer { padding: 12px 20px; border-top: 1px solid var(--tg-border); }
.read-more { font-size: 0.875rem; color: var(--tg-blue); font-weight: 600; }
.read-more:hover { text-decoration: underline; }

/* ============================================================
   列表页
   ============================================================ */
.list-layout { display: grid; grid-template-columns: 1fr 300px; gap: 32px; padding: 48px 0; }
.list-main {}
.list-sidebar {}

.page-title-bar {
  background: linear-gradient(135deg, var(--tg-bg-section), #d8eef9);
  padding: 40px 0;
  border-bottom: 1px solid var(--tg-border);
}
.page-title-bar h1 { font-size: 1.8rem; font-weight: 800; color: var(--tg-text); }
.page-title-bar p { font-size: 1rem; color: var(--tg-text-muted); margin-top: 8px; }

.article-list { display: flex; flex-direction: column; gap: 20px; }
.article-item {
  display: flex;
  gap: 20px;
  background: #fff;
  border: 1px solid var(--tg-border);
  border-radius: var(--tg-radius);
  padding: 20px;
  transition: all .25s;
}
.article-item:hover { border-color: var(--tg-blue); box-shadow: var(--tg-shadow-hover); transform: translateX(4px); }
.article-item-thumb {
  width: 140px;
  height: 100px;
  object-fit: cover;
  border-radius: var(--tg-radius-sm);
  flex-shrink: 0;
}
.article-item-thumb-placeholder {
  width: 140px;
  height: 100px;
  background: linear-gradient(135deg, var(--tg-bg-section), #c8e8f8);
  border-radius: var(--tg-radius-sm);
  flex-shrink: 0;
  display: flex; align-items: center; justify-content: center;
  font-size: 2rem;
}
.article-item-body { flex: 1; }
.article-item-meta { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.article-item-cat { background: var(--tg-bg-section); color: var(--tg-blue); font-size: 0.75rem; font-weight: 600; padding: 3px 10px; border-radius: 20px; }
.article-item-date { font-size: 0.8rem; color: var(--tg-text-light); }
.article-item-views { font-size: 0.8rem; color: var(--tg-text-light); }
.article-item-title { font-size: 1.05rem; font-weight: 700; margin-bottom: 8px; }
.article-item-title a { color: var(--tg-text); }
.article-item-title a:hover { color: var(--tg-blue); }
.article-item-excerpt { font-size: 0.875rem; color: var(--tg-text-muted); line-height: 1.6; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }

/* 分页 */
.pagination { display: flex; justify-content: center; align-items: center; gap: 8px; margin-top: 40px; }
.page-btn {
  display: flex; align-items: center; justify-content: center;
  width: 40px; height: 40px;
  border-radius: 8px;
  border: 1px solid var(--tg-border);
  color: var(--tg-text);
  font-size: 0.9rem;
  font-weight: 500;
  transition: all .2s;
  text-decoration: none;
}
.page-btn:hover, .page-btn.active { background: var(--tg-blue); color: #fff; border-color: var(--tg-blue); text-decoration: none; }
.page-btn.active { pointer-events: none; }

/* 侧边栏 */
.sidebar-widget {
  background: #fff;
  border: 1px solid var(--tg-border);
  border-radius: var(--tg-radius);
  padding: 24px;
  margin-bottom: 24px;
}
.sidebar-widget-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--tg-text);
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--tg-blue);
  display: flex; align-items: center; gap: 8px;
}
.sidebar-list { display: flex; flex-direction: column; gap: 12px; }
.sidebar-list-item { display: flex; gap: 12px; align-items: flex-start; }
.sidebar-list-num {
  width: 24px; height: 24px;
  background: var(--tg-bg-section);
  color: var(--tg-blue);
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
}
.sidebar-list-item a { font-size: 0.875rem; color: var(--tg-text); line-height: 1.5; }
.sidebar-list-item a:hover { color: var(--tg-blue); }
.sidebar-list-item .meta { font-size: 0.75rem; color: var(--tg-text-light); margin-top: 2px; }

/* 标签云 */
.tag-cloud { display: flex; flex-wrap: wrap; gap: 8px; }
.tag-item {
  background: var(--tg-bg-section);
  color: var(--tg-blue);
  font-size: 0.8rem;
  padding: 5px 12px;
  border-radius: 20px;
  border: 1px solid var(--tg-border);
  transition: all .2s;
  text-decoration: none;
}
.tag-item:hover { background: var(--tg-blue); color: #fff; border-color: var(--tg-blue); text-decoration: none; }

/* ============================================================
   内容页
   ============================================================ */
.article-layout { display: grid; grid-template-columns: 1fr 300px; gap: 32px; padding: 48px 0; }
.article-main {}
.article-content-box {
  background: #fff;
  border: 1px solid var(--tg-border);
  border-radius: var(--tg-radius);
  padding: 40px;
}
.article-header { margin-bottom: 28px; }
.article-header h1 {
  font-size: 1.7rem;
  font-weight: 800;
  color: var(--tg-text);
  line-height: 1.4;
  margin-bottom: 16px;
}
.article-meta { display: flex; flex-wrap: wrap; align-items: center; gap: 16px; color: var(--tg-text-muted); font-size: 0.875rem; }
.article-meta-item { display: flex; align-items: center; gap: 5px; }
.article-cover { width: 100%; border-radius: var(--tg-radius-sm); margin-bottom: 28px; max-height: 400px; object-fit: cover; }
.article-body { font-size: 1rem; line-height: 1.85; color: var(--tg-text); }
.article-body h2 { font-size: 1.4rem; font-weight: 700; margin: 32px 0 16px; color: var(--tg-text); }
.article-body h3 { font-size: 1.2rem; font-weight: 700; margin: 24px 0 12px; color: var(--tg-text); }
.article-body p { margin-bottom: 16px; }
.article-body ul, .article-body ol { margin: 16px 0 16px 24px; }
.article-body ul { list-style: disc; }
.article-body ol { list-style: decimal; }
.article-body li { margin-bottom: 8px; }
.article-body blockquote {
  border-left: 4px solid var(--tg-blue);
  background: var(--tg-bg-section);
  padding: 16px 20px;
  margin: 20px 0;
  border-radius: 0 8px 8px 0;
  font-style: italic;
  color: var(--tg-text-muted);
}
.article-body img { border-radius: var(--tg-radius-sm); margin: 16px 0; }
.article-body a { color: var(--tg-blue); }
.article-body table { width: 100%; border-collapse: collapse; margin: 20px 0; }
.article-body th { background: var(--tg-bg-section); padding: 10px 14px; text-align: left; font-weight: 600; border: 1px solid var(--tg-border); }
.article-body td { padding: 10px 14px; border: 1px solid var(--tg-border); }
.article-body tr:nth-child(even) td { background: var(--tg-bg-light); }

/* 文章标签 */
.article-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 28px; padding-top: 20px; border-top: 1px solid var(--tg-border); }
.article-tags-label { font-size: 0.875rem; font-weight: 600; color: var(--tg-text-muted); }

/* 相关文章 */
.related-articles { margin-top: 32px; }
.related-articles h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 16px; }
.related-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.related-item {
  background: var(--tg-bg-light);
  border: 1px solid var(--tg-border);
  border-radius: var(--tg-radius-sm);
  padding: 16px;
  transition: all .2s;
}
.related-item:hover { border-color: var(--tg-blue); background: var(--tg-bg-section); }
.related-item a { font-size: 0.9rem; font-weight: 600; color: var(--tg-text); line-height: 1.5; display: block; margin-bottom: 6px; }
.related-item a:hover { color: var(--tg-blue); text-decoration: none; }
.related-item .meta { font-size: 0.78rem; color: var(--tg-text-light); }

/* ============================================================
   下载页
   ============================================================ */
.download-hero {
  background: linear-gradient(135deg, #1a8cc7 0%, #2AABEE 60%, #5ec8f5 100%);
  padding: 72px 0;
  text-align: center;
  color: #fff;
}
.download-hero h1 { font-size: 2.4rem; font-weight: 800; margin-bottom: 16px; }
.download-hero p { font-size: 1.1rem; opacity: 0.9; max-width: 560px; margin: 0 auto 32px; }
.download-hero .version-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,255,255,0.2);
  padding: 8px 20px;
  border-radius: 20px;
  font-size: 0.9rem;
  margin-bottom: 32px;
}

.platforms-section { padding: 72px 0; }
.platforms-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
  margin-top: 40px;
}
.platform-card {
  background: #fff;
  border: 1px solid var(--tg-border);
  border-radius: var(--tg-radius);
  padding: 36px 28px;
  text-align: center;
  box-shadow: var(--tg-shadow);
  transition: all .25s;
}
.platform-card:hover { border-color: var(--tg-blue); box-shadow: var(--tg-shadow-hover); transform: translateY(-6px); }
.platform-icon { font-size: 3rem; margin-bottom: 16px; }
.platform-card h3 { font-size: 1.2rem; font-weight: 700; margin-bottom: 8px; }
.platform-card p { font-size: 0.9rem; color: var(--tg-text-muted); margin-bottom: 20px; }
.platform-card .btn-dl {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--tg-blue);
  color: #fff;
  padding: 12px 28px;
  border-radius: 24px;
  font-size: 0.95rem;
  font-weight: 700;
  text-decoration: none;
  transition: background .2s;
}
.platform-card .btn-dl:hover { background: var(--tg-dark-blue); color: #fff; text-decoration: none; }
.platform-card .btn-dl-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: transparent;
  color: var(--tg-blue);
  padding: 10px 20px;
  border-radius: 24px;
  font-size: 0.875rem;
  font-weight: 600;
  text-decoration: none;
  border: 1.5px solid var(--tg-blue);
  margin-top: 8px;
  transition: all .2s;
}
.platform-card .btn-dl-secondary:hover { background: var(--tg-bg-section); text-decoration: none; }

/* 下载步骤 */
.steps-section { padding: 72px 0; background: var(--tg-bg-light); }
.steps-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; margin-top: 40px; }
.step-item { text-align: center; }
.step-num {
  width: 56px; height: 56px;
  background: var(--tg-blue);
  color: #fff;
  border-radius: 50%;
  font-size: 1.4rem;
  font-weight: 800;
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 16px;
  box-shadow: 0 4px 16px rgba(42,171,238,0.3);
}
.step-item h3 { font-size: 1rem; font-weight: 700; margin-bottom: 8px; }
.step-item p { font-size: 0.875rem; color: var(--tg-text-muted); }

/* FAQ */
.faq-section { padding: 72px 0; }
.faq-list { max-width: 760px; margin: 40px auto 0; }
.faq-item {
  border: 1px solid var(--tg-border);
  border-radius: var(--tg-radius-sm);
  margin-bottom: 12px;
  overflow: hidden;
}
.faq-question {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 18px 20px;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.95rem;
  background: #fff;
  transition: background .2s;
}
.faq-question:hover { background: var(--tg-bg-section); }
.faq-question .icon { color: var(--tg-blue); font-size: 1.2rem; transition: transform .3s; }
.faq-item.open .faq-question .icon { transform: rotate(45deg); }
.faq-answer { display: none; padding: 0 20px 18px; font-size: 0.9rem; color: var(--tg-text-muted); line-height: 1.7; background: #fff; }
.faq-item.open .faq-answer { display: block; }

/* ============================================================
   统计数据
   ============================================================ */
.stats-section { padding: 56px 0; background: linear-gradient(135deg, #1a8cc7, #2AABEE); color: #fff; }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; text-align: center; }
.stat-item {}
.stat-num { font-size: 2.4rem; font-weight: 800; margin-bottom: 6px; }
.stat-label { font-size: 0.9rem; opacity: 0.85; }

/* ============================================================
   CTA 区块
   ============================================================ */
.cta-section {
  padding: 72px 0;
  background: var(--tg-bg-light);
  text-align: center;
}
.cta-section h2 { font-size: 2rem; font-weight: 800; margin-bottom: 16px; }
.cta-section p { font-size: 1.05rem; color: var(--tg-text-muted); margin-bottom: 32px; max-width: 520px; margin-left: auto; margin-right: auto; }

/* ============================================================
   页脚
   ============================================================ */
.site-footer {
  background: #1a2a3a;
  color: #b0c4d8;
  padding: 56px 0 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}
.footer-brand { }
.footer-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
  text-decoration: none;
}
.footer-logo img { width: 36px; height: 36px; border-radius: 50%; }
.footer-logo span { font-size: 1.2rem; font-weight: 700; color: #fff; }
.footer-brand p { font-size: 0.875rem; line-height: 1.7; color: #8aa4bb; }
.footer-social { display: flex; gap: 10px; margin-top: 16px; }
.footer-social a {
  width: 36px; height: 36px;
  background: rgba(255,255,255,0.08);
  border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  color: #b0c4d8;
  font-size: 0.9rem;
  transition: background .2s, color .2s;
  text-decoration: none;
}
.footer-social a:hover { background: var(--tg-blue); color: #fff; }
.footer-col h4 { font-size: 0.95rem; font-weight: 700; color: #fff; margin-bottom: 16px; }
.footer-col ul { display: flex; flex-direction: column; gap: 10px; }
.footer-col ul li a { font-size: 0.875rem; color: #8aa4bb; transition: color .2s; }
.footer-col ul li a:hover { color: var(--tg-blue); text-decoration: none; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding: 20px 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 0.8rem;
  color: #6a8aa0;
}
.footer-bottom a { color: #6a8aa0; }
.footer-bottom a:hover { color: var(--tg-blue); }

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 1024px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .news-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .steps-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .hero-title { font-size: 2rem; }
  .list-layout, .article-layout { grid-template-columns: 1fr; }
  .list-sidebar, .article-sidebar { order: -1; }
  .download-grid, .platforms-grid { grid-template-columns: 1fr; }
  .related-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .main-nav { display: none; }
  .menu-toggle { display: flex; }
  .main-nav.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 64px; left: 0; right: 0;
    background: #fff;
    border-bottom: 1px solid var(--tg-border);
    padding: 12px 16px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.1);
    z-index: 999;
  }
  .header-inner { position: relative; }
  .carousel-slide img { height: 240px; }
  .features-grid { grid-template-columns: 1fr; }
  .news-grid { grid-template-columns: 1fr; }
  .steps-grid { grid-template-columns: repeat(2, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .article-content-box { padding: 24px 16px; }
}

@media (max-width: 480px) {
  .hero-title { font-size: 1.6rem; }
  .hero-actions { flex-direction: column; align-items: center; }
  .steps-grid { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; text-align: center; }
}

/* ============================================================
   工具类
   ============================================================ */
.text-center { text-align: center; }
.text-blue { color: var(--tg-blue); }
.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; }
.mb-24 { margin-bottom: 24px; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }