/* ===== 谷歌浏览器下载 - 主样式文件 ===== */
/* 遵循谷歌SEO/EEAT标准，响应式设计 */

:root {
  --chrome-blue: #1a73e8;
  --chrome-blue-dark: #1557b0;
  --chrome-blue-light: #e8f0fe;
  --chrome-red: #ea4335;
  --chrome-green: #34a853;
  --chrome-yellow: #fbbc04;
  --text-primary: #202124;
  --text-secondary: #5f6368;
  --text-light: #80868b;
  --bg-white: #ffffff;
  --bg-light: #f8f9fa;
  --bg-gray: #f1f3f4;
  --border-color: #dadce0;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 25px rgba(0,0,0,0.1), 0 4px 10px rgba(0,0,0,0.06);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

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

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

body {
  font-family: 'Google Sans', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif;
  color: var(--text-primary);
  background-color: var(--bg-white);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--chrome-blue);
  text-decoration: none;
  transition: var(--transition);
}

a:hover {
  color: var(--chrome-blue-dark);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

ul, ol {
  list-style: none;
}

/* ===== 通用容器 ===== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 80px 0;
}

.section-sm {
  padding: 48px 0;
}

/* ===== 按钮样式 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius-xl);
  font-size: 15px;
  font-weight: 500;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--chrome-blue);
  color: #fff;
  box-shadow: 0 2px 6px rgba(26, 115, 232, 0.35);
}

.btn-primary:hover {
  background-color: var(--chrome-blue-dark);
  color: #fff;
  box-shadow: 0 4px 12px rgba(26, 115, 232, 0.45);
  transform: translateY(-1px);
}

.btn-outline {
  background-color: transparent;
  color: var(--chrome-blue);
  border: 1.5px solid var(--chrome-blue);
}

.btn-outline:hover {
  background-color: var(--chrome-blue-light);
  color: var(--chrome-blue-dark);
}

.btn-white {
  background-color: #fff;
  color: var(--chrome-blue);
  box-shadow: var(--shadow-md);
}

.btn-white:hover {
  background-color: var(--bg-light);
  color: var(--chrome-blue-dark);
  box-shadow: var(--shadow-lg);
}

.btn-lg {
  padding: 16px 36px;
  font-size: 16px;
  border-radius: var(--radius-xl);
}

.btn-icon {
  width: 20px;
  height: 20px;
}

/* ===== 顶部导航 ===== */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: rgba(255,255,255,0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition);
}

.header.scrolled {
  box-shadow: var(--shadow-sm);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 32px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
  text-decoration: none;
  flex-shrink: 0;
}

.logo-icon {
  width: 32px;
  height: 32px;
}

.logo-text {
  color: var(--text-primary);
}

.logo-text span {
  color: var(--chrome-blue);
}

/* 主导航 */
.nav {
  display: flex;
  align-items: center;
  gap: 4px;
  flex: 1;
}

.nav-link {
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  transition: var(--transition);
  white-space: nowrap;
}

.nav-link:hover,
.nav-link.active {
  color: var(--chrome-blue);
  background-color: var(--chrome-blue-light);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

/* 移动端菜单按钮 */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 8px;
  border-radius: var(--radius-sm);
  background: none;
  border: none;
}

.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition);
}

/* ===== 轮播图 ===== */
.carousel {
  position: relative;
  overflow: hidden;
  border-radius: 0;
  background: linear-gradient(135deg, #e8f0fe 0%, #f0f4ff 50%, #e8f5e9 100%);
}

.carousel-track {
  display: flex;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.carousel-slide {
  min-width: 100%;
  position: relative;
  overflow: hidden;
}

.carousel-slide img {
  width: 100%;
  height: 520px;
  object-fit: cover;
  object-position: center;
}

.carousel-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to right, rgba(0,0,0,0.55) 0%, rgba(0,0,0,0.2) 50%, transparent 100%);
  display: flex;
  align-items: center;
}

.carousel-content {
  padding: 0 80px;
  max-width: 600px;
  color: #fff;
}

.carousel-content .tag {
  display: inline-block;
  background: rgba(255,255,255,0.2);
  border: 1px solid rgba(255,255,255,0.4);
  color: #fff;
  padding: 4px 14px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 500;
  margin-bottom: 16px;
  backdrop-filter: blur(4px);
}

.carousel-content h2 {
  font-size: 42px;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 16px;
  text-shadow: 0 2px 8px rgba(0,0,0,0.2);
}

.carousel-content p {
  font-size: 17px;
  line-height: 1.6;
  margin-bottom: 28px;
  opacity: 0.92;
}

.carousel-content .btn-group {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.carousel-nav {
  position: absolute;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 8px;
  z-index: 10;
}

.carousel-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba(255,255,255,0.5);
  cursor: pointer;
  transition: var(--transition);
  border: none;
}

.carousel-dot.active {
  width: 24px;
  border-radius: 4px;
  background: #fff;
}

.carousel-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: rgba(255,255,255,0.9);
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  transition: var(--transition);
  z-index: 10;
}

.carousel-btn:hover {
  background: #fff;
  box-shadow: var(--shadow-lg);
  transform: translateY(-50%) scale(1.05);
}

.carousel-btn-prev { left: 20px; }
.carousel-btn-next { right: 20px; }

.carousel-btn svg {
  width: 20px;
  height: 20px;
  color: var(--text-primary);
}

/* ===== 首页 Hero 区域 ===== */
.hero {
  background: linear-gradient(135deg, #e8f0fe 0%, #f8f9ff 40%, #e8f5e9 100%);
  padding: 80px 0 60px;
  overflow: hidden;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.hero-content h1 {
  font-size: 52px;
  font-weight: 700;
  line-height: 1.15;
  color: var(--text-primary);
  margin-bottom: 20px;
}

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

.hero-content p {
  font-size: 18px;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 32px;
}

.hero-meta {
  font-size: 13px;
  color: var(--text-light);
  margin-top: 16px;
}

.hero-image {
  position: relative;
}

.hero-image img {
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
}

.hero-badge {
  position: absolute;
  bottom: -20px;
  left: -20px;
  background: #fff;
  border-radius: var(--radius-md);
  padding: 12px 20px;
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 10px;
}

.hero-badge .badge-icon {
  width: 36px;
  height: 36px;
  background: var(--chrome-blue-light);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero-badge .badge-text strong {
  display: block;
  font-size: 15px;
  font-weight: 600;
  color: var(--text-primary);
}

.hero-badge .badge-text span {
  font-size: 12px;
  color: var(--text-light);
}

/* ===== 统计数字 ===== */
.stats {
  background: var(--bg-white);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
  padding: 40px 0;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
}

.stat-item {
  text-align: center;
  padding: 20px;
  border-right: 1px solid var(--border-color);
}

.stat-item:last-child {
  border-right: none;
}

.stat-number {
  font-size: 40px;
  font-weight: 700;
  color: var(--chrome-blue);
  line-height: 1;
  margin-bottom: 8px;
}

.stat-label {
  font-size: 14px;
  color: var(--text-secondary);
}

/* ===== 功能特性 ===== */
.features {
  background: var(--bg-white);
}

.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-tag {
  display: inline-block;
  background: var(--chrome-blue-light);
  color: var(--chrome-blue);
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 16px;
  letter-spacing: 0.5px;
}

.section-title {
  font-size: 36px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 16px;
  line-height: 1.25;
}

.section-desc {
  font-size: 17px;
  color: var(--text-secondary);
  max-width: 560px;
  margin: 0 auto;
  line-height: 1.7;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.feature-card {
  background: var(--bg-light);
  border-radius: var(--radius-md);
  padding: 32px 28px;
  transition: var(--transition);
  border: 1px solid transparent;
}

.feature-card:hover {
  background: var(--bg-white);
  border-color: var(--border-color);
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
}

.feature-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  font-size: 24px;
}

.feature-icon.blue { background: var(--chrome-blue-light); }
.feature-icon.green { background: #e6f4ea; }
.feature-icon.yellow { background: #fef7e0; }
.feature-icon.red { background: #fce8e6; }
.feature-icon.purple { background: #f3e8fd; }
.feature-icon.teal { background: #e6f4f1; }

.feature-card h3 {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.feature-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

.feature-card .feature-img {
  width: 100%;
  height: 180px;
  object-fit: cover;
  border-radius: var(--radius-sm);
  margin-bottom: 20px;
}

/* ===== 安全性区域 ===== */
.security {
  background: linear-gradient(135deg, #1a73e8 0%, #0d47a1 100%);
  color: #fff;
}

.security .section-tag {
  background: rgba(255,255,255,0.2);
  color: #fff;
}

.security .section-title {
  color: #fff;
}

.security .section-desc {
  color: rgba(255,255,255,0.85);
}

.security-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}

.security-list {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.security-item {
  display: flex;
  gap: 16px;
  align-items: flex-start;
}

.security-item-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: rgba(255,255,255,0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  flex-shrink: 0;
}

.security-item-content h4 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 6px;
}

.security-item-content p {
  font-size: 14px;
  opacity: 0.85;
  line-height: 1.6;
}

.security-image img {
  border-radius: var(--radius-lg);
  box-shadow: 0 20px 60px rgba(0,0,0,0.3);
}

/* ===== 下载区域 ===== */
.download-cta {
  background: var(--bg-light);
  text-align: center;
}

.download-cta .section-title {
  font-size: 40px;
}

.download-options {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-top: 40px;
  flex-wrap: wrap;
}

.download-card {
  background: #fff;
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 28px 36px;
  text-align: center;
  transition: var(--transition);
  min-width: 200px;
}

.download-card:hover {
  border-color: var(--chrome-blue);
  box-shadow: var(--shadow-md);
  transform: translateY(-3px);
}

.download-card-icon {
  font-size: 40px;
  margin-bottom: 12px;
}

.download-card h4 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.download-card p {
  font-size: 13px;
  color: var(--text-light);
  margin-bottom: 16px;
}

/* ===== 资讯列表 ===== */
.news {
  background: var(--bg-white);
}

.news-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.news-card {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
}

.news-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-4px);
  border-color: transparent;
}

.news-card-img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  transition: transform 0.4s ease;
}

.news-card:hover .news-card-img {
  transform: scale(1.03);
}

.news-card-img-wrap {
  overflow: hidden;
}

.news-card-body {
  padding: 20px;
}

.news-card-tags {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-bottom: 10px;
}

.tag-badge {
  display: inline-block;
  background: var(--chrome-blue-light);
  color: var(--chrome-blue);
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 500;
}

.news-card-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.5;
  margin-bottom: 10px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.news-card-title a {
  color: inherit;
}

.news-card-title a:hover {
  color: var(--chrome-blue);
}

.news-card-desc {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 14px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.news-card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 12px;
  color: var(--text-light);
}

.news-card-author {
  display: flex;
  align-items: center;
  gap: 6px;
}

.author-avatar {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--chrome-blue-light);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  color: var(--chrome-blue);
  font-weight: 600;
}

/* ===== 面包屑 ===== */
.breadcrumb {
  padding: 16px 0;
  border-bottom: 1px solid var(--border-color);
  background: var(--bg-white);
}

.breadcrumb-list {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  color: var(--text-secondary);
}

.breadcrumb-list li:not(:last-child)::after {
  content: '/';
  margin-left: 6px;
  color: var(--text-light);
}

.breadcrumb-list a {
  color: var(--chrome-blue);
}

.breadcrumb-list .current {
  color: var(--text-primary);
  font-weight: 500;
}

/* ===== 分页 ===== */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 8px;
  margin-top: 48px;
}

.page-btn {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  border: 1.5px solid var(--border-color);
  background: var(--bg-white);
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
}

.page-btn:hover,
.page-btn.active {
  background: var(--chrome-blue);
  color: #fff;
  border-color: var(--chrome-blue);
}

/* ===== 内容页 ===== */
.article-header {
  padding: 48px 0 32px;
  border-bottom: 1px solid var(--border-color);
}

.article-header h1 {
  font-size: 36px;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 16px;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 20px;
  font-size: 14px;
  color: var(--text-secondary);
  flex-wrap: wrap;
}

.article-meta-item {
  display: flex;
  align-items: center;
  gap: 6px;
}

.article-content {
  padding: 40px 0;
}

.article-content h2 {
  font-size: 26px;
  font-weight: 700;
  color: var(--text-primary);
  margin: 36px 0 16px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--chrome-blue-light);
}

.article-content h3 {
  font-size: 20px;
  font-weight: 600;
  color: var(--text-primary);
  margin: 28px 0 12px;
}

.article-content p {
  font-size: 16px;
  line-height: 1.8;
  color: var(--text-primary);
  margin-bottom: 20px;
}

.article-content ul,
.article-content ol {
  margin: 16px 0 20px 24px;
}

.article-content ul { list-style: disc; }
.article-content ol { list-style: decimal; }

.article-content li {
  font-size: 16px;
  line-height: 1.8;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.article-content img {
  border-radius: var(--radius-md);
  margin: 24px 0;
  box-shadow: var(--shadow-sm);
}

.article-content blockquote {
  border-left: 4px solid var(--chrome-blue);
  background: var(--chrome-blue-light);
  padding: 16px 20px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 24px 0;
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.7;
}

.article-content code {
  background: var(--bg-gray);
  padding: 2px 8px;
  border-radius: 4px;
  font-family: 'Roboto Mono', monospace;
  font-size: 14px;
  color: var(--chrome-red);
}

.article-content pre {
  background: #1e1e2e;
  color: #cdd6f4;
  padding: 20px;
  border-radius: var(--radius-sm);
  overflow-x: auto;
  margin: 20px 0;
  font-size: 14px;
  line-height: 1.6;
}

.article-content pre code {
  background: none;
  color: inherit;
  padding: 0;
}

/* 文章侧边栏 */
.article-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 48px;
  align-items: start;
}

.sidebar {
  position: sticky;
  top: 80px;
}

.sidebar-widget {
  background: var(--bg-light);
  border-radius: var(--radius-md);
  padding: 24px;
  margin-bottom: 24px;
}

.sidebar-widget h4 {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--chrome-blue);
}

.sidebar-list li {
  padding: 10px 0;
  border-bottom: 1px solid var(--border-color);
}

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

.sidebar-list a {
  font-size: 14px;
  color: var(--text-secondary);
  display: flex;
  align-items: flex-start;
  gap: 8px;
  line-height: 1.5;
}

.sidebar-list a:hover {
  color: var(--chrome-blue);
}

.sidebar-list a::before {
  content: '›';
  color: var(--chrome-blue);
  font-weight: 700;
  flex-shrink: 0;
  margin-top: 1px;
}

/* ===== 下载页 ===== */
.download-hero {
  background: linear-gradient(135deg, #e8f0fe 0%, #f0f4ff 100%);
  padding: 80px 0;
  text-align: center;
}

.download-hero h1 {
  font-size: 48px;
  font-weight: 700;
  margin-bottom: 20px;
}

.download-hero p {
  font-size: 18px;
  color: var(--text-secondary);
  margin-bottom: 40px;
}

.version-info {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: #fff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 8px 20px;
  font-size: 14px;
  color: var(--text-secondary);
  margin-top: 20px;
}

.version-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--chrome-green);
}

.download-platforms {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 60px;
}

.platform-card {
  background: #fff;
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 36px 28px;
  text-align: center;
  transition: var(--transition);
}

.platform-card:hover,
.platform-card.featured {
  border-color: var(--chrome-blue);
  box-shadow: 0 0 0 3px rgba(26, 115, 232, 0.1);
}

.platform-card.featured {
  position: relative;
}

.platform-badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--chrome-blue);
  color: #fff;
  padding: 4px 16px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 600;
  white-space: nowrap;
}

.platform-icon {
  font-size: 48px;
  margin-bottom: 16px;
}

.platform-card h3 {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 8px;
}

.platform-card .version {
  font-size: 14px;
  color: var(--text-light);
  margin-bottom: 6px;
}

.platform-card .size {
  font-size: 13px;
  color: var(--text-light);
  margin-bottom: 24px;
}

.install-steps {
  background: var(--bg-light);
  padding: 80px 0;
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-top: 48px;
}

.step-item {
  text-align: center;
  padding: 28px 20px;
  background: #fff;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  position: relative;
}

.step-number {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--chrome-blue);
  color: #fff;
  font-size: 18px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
}

.step-item h4 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
}

.step-item p {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ===== FAQ ===== */
.faq {
  background: var(--bg-white);
}

.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
  overflow: hidden;
}

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 24px;
  cursor: pointer;
  font-size: 16px;
  font-weight: 500;
  color: var(--text-primary);
  background: var(--bg-white);
  transition: var(--transition);
  user-select: none;
}

.faq-question:hover {
  background: var(--bg-light);
}

.faq-question.open {
  color: var(--chrome-blue);
  background: var(--chrome-blue-light);
}

.faq-icon {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--bg-gray);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  flex-shrink: 0;
  transition: var(--transition);
}

.faq-question.open .faq-icon {
  background: var(--chrome-blue);
  color: #fff;
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
}

.faq-answer.open {
  max-height: 400px;
}

.faq-answer-inner {
  padding: 0 24px 20px;
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ===== 页脚 ===== */
.footer {
  background: var(--text-primary);
  color: rgba(255,255,255,0.75);
  padding: 60px 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 48px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}

.footer-brand .logo {
  color: #fff;
  margin-bottom: 16px;
}

.footer-brand p {
  font-size: 14px;
  line-height: 1.7;
  margin-bottom: 20px;
}

.footer-social {
  display: flex;
  gap: 10px;
}

.social-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: rgba(255,255,255,0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(255,255,255,0.7);
  font-size: 14px;
  transition: var(--transition);
  text-decoration: none;
}

.social-btn:hover {
  background: var(--chrome-blue);
  color: #fff;
}

.footer-col h5 {
  font-size: 14px;
  font-weight: 600;
  color: #fff;
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links a {
  font-size: 14px;
  color: rgba(255,255,255,0.65);
  transition: var(--transition);
}

.footer-links a:hover {
  color: #fff;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 0;
  font-size: 13px;
  color: rgba(255,255,255,0.5);
  flex-wrap: wrap;
  gap: 12px;
}

.footer-bottom-links {
  display: flex;
  gap: 20px;
}

.footer-bottom-links a {
  color: rgba(255,255,255,0.5);
  font-size: 13px;
}

.footer-bottom-links a:hover {
  color: rgba(255,255,255,0.8);
}

/* ===== 列表页 ===== */
.list-header {
  background: linear-gradient(135deg, #e8f0fe 0%, #f0f4ff 100%);
  padding: 48px 0;
  text-align: center;
}

.list-header h1 {
  font-size: 36px;
  font-weight: 700;
  margin-bottom: 12px;
}

.list-header p {
  font-size: 17px;
  color: var(--text-secondary);
}

.list-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 48px;
  padding: 48px 0;
  align-items: start;
}

.list-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

.list-card {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 24px;
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
}

.list-card:hover {
  box-shadow: var(--shadow-md);
  border-color: transparent;
}

.list-card-img {
  width: 100%;
  height: 160px;
  object-fit: cover;
}

.list-card-body {
  padding: 20px 20px 20px 0;
  display: flex;
  flex-direction: column;
}

.list-card-tags {
  display: flex;
  gap: 6px;
  margin-bottom: 10px;
}

.list-card-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.4;
  margin-bottom: 10px;
}

.list-card-title a {
  color: inherit;
}

.list-card-title a:hover {
  color: var(--chrome-blue);
}

.list-card-desc {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.6;
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.list-card-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 14px;
  font-size: 13px;
  color: var(--text-light);
}

/* ===== 搜索框 ===== */
.search-box {
  position: relative;
  margin-bottom: 24px;
}

.search-box input {
  width: 100%;
  padding: 12px 16px 12px 44px;
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-xl);
  font-size: 14px;
  color: var(--text-primary);
  background: var(--bg-white);
  outline: none;
  transition: var(--transition);
}

.search-box input:focus {
  border-color: var(--chrome-blue);
  box-shadow: 0 0 0 3px rgba(26, 115, 232, 0.1);
}

.search-box-icon {
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-light);
  font-size: 16px;
}

/* ===== 分类标签 ===== */
.category-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 24px;
}

.cat-tag {
  padding: 6px 16px;
  border-radius: var(--radius-xl);
  font-size: 13px;
  font-weight: 500;
  border: 1.5px solid var(--border-color);
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition);
  background: var(--bg-white);
  text-decoration: none;
}

.cat-tag:hover,
.cat-tag.active {
  background: var(--chrome-blue);
  color: #fff;
  border-color: var(--chrome-blue);
}

/* ===== 通知条 ===== */
.notice-bar {
  background: var(--chrome-blue);
  color: #fff;
  text-align: center;
  padding: 10px 24px;
  font-size: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
}

.notice-bar a {
  color: #fff;
  font-weight: 600;
  text-decoration: underline;
}

.notice-close {
  background: none;
  border: none;
  color: rgba(255,255,255,0.7);
  cursor: pointer;
  font-size: 18px;
  padding: 0;
  margin-left: 8px;
  line-height: 1;
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .hero-inner {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 40px;
  }

  .hero-content h1 {
    font-size: 40px;
  }

  .hero-image {
    max-width: 500px;
    margin: 0 auto;
  }

  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .security-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }

  .article-layout,
  .list-layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
  }

  .download-platforms {
    grid-template-columns: 1fr;
    max-width: 400px;
    margin: 60px auto 0;
  }

  .steps-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .container {
    padding: 0 16px;
  }

  .section {
    padding: 56px 0;
  }

  .section-title {
    font-size: 28px;
  }

  .nav {
    display: none;
    position: fixed;
    top: 64px;
    left: 0;
    right: 0;
    background: #fff;
    padding: 16px;
    flex-direction: column;
    align-items: stretch;
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
    z-index: 999;
  }

  .nav.open {
    display: flex;
  }

  .nav-link {
    padding: 12px 16px;
    font-size: 15px;
  }

  .menu-toggle {
    display: flex;
  }

  .header-actions .btn {
    display: none;
  }

  .hero-content h1 {
    font-size: 32px;
  }

  .carousel-slide img {
    height: 320px;
  }

  .carousel-content {
    padding: 0 40px;
  }

  .carousel-content h2 {
    font-size: 28px;
  }

  .features-grid {
    grid-template-columns: 1fr;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .stat-item:nth-child(2) {
    border-right: none;
  }

  .news-grid {
    grid-template-columns: 1fr;
  }

  .list-card {
    grid-template-columns: 1fr;
  }

  .list-card-img {
    height: 200px;
  }

  .list-card-body {
    padding: 16px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }

  .steps-grid {
    grid-template-columns: 1fr;
  }

  .article-header h1 {
    font-size: 26px;
  }

  .download-hero h1 {
    font-size: 32px;
  }
}

/* ===== 工具类 ===== */
.text-center { text-align: center; }
.text-blue { color: var(--chrome-blue); }
.mt-4 { margin-top: 16px; }
.mt-8 { margin-top: 32px; }
.mb-4 { margin-bottom: 16px; }
.mb-8 { margin-bottom: 32px; }
.flex { display: flex; }
.items-center { align-items: center; }
.gap-2 { gap: 8px; }
.gap-4 { gap: 16px; }
.hidden { display: none; }

/* ===== 动画 ===== */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-fadeInUp {
  animation: fadeInUp 0.6s ease forwards;
}

.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }

/* ===== 进度条 ===== */
.progress-bar {
  background: var(--bg-gray);
  border-radius: 4px;
  height: 6px;
  overflow: hidden;
  margin-top: 8px;
}

.progress-fill {
  height: 100%;
  border-radius: 4px;
  background: var(--chrome-blue);
  transition: width 1s ease;
}

/* ===== 徽章 ===== */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 600;
}

.badge-blue { background: var(--chrome-blue-light); color: var(--chrome-blue); }
.badge-green { background: #e6f4ea; color: #137333; }
.badge-red { background: #fce8e6; color: #c5221f; }
.badge-yellow { background: #fef7e0; color: #b06000; }

/* ===== 返回顶部 ===== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--chrome-blue);
  color: #fff;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  transition: var(--transition);
  opacity: 0;
  pointer-events: none;
  z-index: 100;
}

.back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
}

.back-to-top:hover {
  background: var(--chrome-blue-dark);
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}