/* ============================================
   吃瓜网 - 全网内容精选与每日必读推荐
   核心样式文件 v1.0
   ============================================ */

/* CSS变量定义 */
:root {
  --primary: #26A69A;
  --secondary: #00897B;
  --bg: #FFFFFF;
  --card-bg: #E0F2F1;
  --accent: #4DB6AC;
  --text: #1A1A1A;
  --text-light: #555555;
  --text-muted: #888888;
  --border: #E0E0E0;
  --shadow: rgba(0, 0, 0, 0.08);
  --shadow-hover: rgba(38, 166, 154, 0.15);
  --radius: 12px;
  --radius-sm: 8px;
  --radius-lg: 16px;
  --transition: all 0.3s ease;
  --font-main: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
  --font-mono: 'Roboto', 'SF Mono', monospace;
  --max-width: 1200px;
  --header-height: 64px;
}

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

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

body {
  font-family: var(--font-main);
  color: var(--text);
  background-color: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a:hover {
  color: var(--secondary);
}

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

ul, ol {
  list-style: none;
}

/* ============================================
   导航栏
   ============================================ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
  transition: var(--transition);
}

.header.scrolled {
  box-shadow: 0 2px 20px var(--shadow);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--primary);
}

.logo img {
  width: 36px;
  height: 36px;
  border-radius: 8px;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-menu a {
  color: var(--text);
  font-size: 0.95rem;
  font-weight: 500;
  position: relative;
  padding: 4px 0;
}

.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  transition: var(--transition);
}

.nav-menu a:hover::after,
.nav-menu a.active::after {
  width: 100%;
}

.nav-menu a:hover {
  color: var(--primary);
}

.search-box {
  display: flex;
  align-items: center;
  background: var(--card-bg);
  border-radius: 24px;
  padding: 8px 16px;
  gap: 8px;
  min-width: 200px;
}

.search-box input {
  border: none;
  background: transparent;
  outline: none;
  font-size: 0.9rem;
  width: 100%;
  color: var(--text);
}

.search-box button {
  border: none;
  background: var(--primary);
  color: white;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.search-box button:hover {
  background: var(--secondary);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text);
}

/* ============================================
   轮播区
   ============================================ */
.hero-carousel {
  margin-top: var(--header-height);
  position: relative;
  overflow: hidden;
  border-radius: 0 0 var(--radius-lg) var(--radius-lg);
}

.carousel-container {
  display: flex;
  transition: transform 0.6s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

.carousel-slide {
  min-width: 100%;
  position: relative;
  aspect-ratio: 16/7;
}

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

.carousel-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(0,0,0,0.6) 0%, rgba(0,0,0,0.2) 100%);
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 60px 80px;
  color: white;
}

.carousel-overlay .tag {
  display: inline-block;
  background: var(--primary);
  color: white;
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.8rem;
  margin-bottom: 16px;
  width: fit-content;
}

.carousel-overlay h2 {
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 12px;
  line-height: 1.3;
  max-width: 600px;
}

.carousel-overlay p {
  font-size: 1rem;
  opacity: 0.9;
  max-width: 500px;
  margin-bottom: 20px;
}

.carousel-overlay .btn-read {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--primary);
  color: white;
  padding: 10px 24px;
  border-radius: 24px;
  font-weight: 500;
  transition: var(--transition);
  width: fit-content;
}

.carousel-overlay .btn-read:hover {
  background: var(--secondary);
  transform: translateX(4px);
}

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

.carousel-dots .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: rgba(255,255,255,0.5);
  cursor: pointer;
  transition: var(--transition);
}

.carousel-dots .dot.active {
  background: var(--primary);
  width: 28px;
  border-radius: 5px;
}

.carousel-nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 44px;
  height: 44px;
  background: rgba(255,255,255,0.9);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  color: var(--text);
  transition: var(--transition);
  box-shadow: 0 2px 10px var(--shadow);
}

.carousel-nav:hover {
  background: var(--primary);
  color: white;
}

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

/* ============================================
   主内容区布局
   ============================================ */
.main-content {
  max-width: var(--max-width);
  margin: 40px auto;
  padding: 0 20px;
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 30px;
}

.content-area {
  min-width: 0;
}

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

/* ============================================
   区块标题
   ============================================ */
.section-title {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--card-bg);
}

.section-title h2 {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 8px;
}

.section-title h2::before {
  content: '';
  width: 4px;
  height: 20px;
  background: var(--primary);
  border-radius: 2px;
}

.section-title .more-link {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.section-title .more-link:hover {
  color: var(--primary);
}

/* ============================================
   内容卡片
   ============================================ */
.card-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin-bottom: 40px;
}

.card {
  background: var(--bg);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  transition: var(--transition);
  position: relative;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px var(--shadow-hover);
  border-color: var(--accent);
}

.card-image {
  position: relative;
  aspect-ratio: 3/2;
  overflow: hidden;
}

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

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

.card-category {
  position: absolute;
  top: 12px;
  left: 12px;
  background: var(--primary);
  color: white;
  padding: 3px 10px;
  border-radius: 12px;
  font-size: 0.75rem;
  font-weight: 500;
}

.card-bookmark {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 32px;
  height: 32px;
  background: rgba(255,255,255,0.9);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  font-size: 1rem;
}

.card-bookmark:hover,
.card-bookmark.active {
  background: var(--accent);
  color: white;
}

.card-body {
  padding: 16px;
}

.card-body h3 {
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: 8px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-body h3 a {
  color: var(--text);
}

.card-body h3 a:hover {
  color: var(--primary);
}

.card-body p {
  font-size: 0.85rem;
  color: var(--text-light);
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: 12px;
}

.card-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.78rem;
  color: var(--text-muted);
}

.card-meta .reading-time {
  display: flex;
  align-items: center;
  gap: 4px;
  color: var(--primary);
  font-weight: 500;
}

/* ============================================
   热门标签云
   ============================================ */
.tag-cloud {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 20px;
}

.tag-cloud-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.tag-cloud-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag-cloud-list a {
  display: inline-block;
  padding: 5px 12px;
  background: white;
  border-radius: 16px;
  font-size: 0.8rem;
  color: var(--text-light);
  border: 1px solid var(--border);
  transition: var(--transition);
}

.tag-cloud-list a:hover {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

.tag-cloud-list a.hot {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

/* ============================================
   每日必读榜单
   ============================================ */
.daily-ranking {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 20px;
}

.daily-ranking-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.ranking-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.ranking-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
}

.ranking-num {
  width: 24px;
  height: 24px;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  color: white;
  background: var(--text-muted);
  flex-shrink: 0;
}

.ranking-item:nth-child(1) .ranking-num { background: #FF5252; }
.ranking-item:nth-child(2) .ranking-num { background: #FF7043; }
.ranking-item:nth-child(3) .ranking-num { background: #FFA726; }

.ranking-item a {
  font-size: 0.85rem;
  color: var(--text);
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.ranking-item a:hover {
  color: var(--primary);
}

.ranking-trend {
  margin-left: auto;
  font-size: 0.7rem;
  flex-shrink: 0;
}

.ranking-trend.up { color: #FF5252; }
.ranking-trend.down { color: #4CAF50; }

/* ============================================
   个性化推荐
   ============================================ */
.recommend-box {
  background: var(--card-bg);
  border-radius: var(--radius);
  padding: 20px;
}

.recommend-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.recommend-loading {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.recommend-loading .dots {
  display: inline-flex;
  gap: 3px;
}

.recommend-loading .dots span {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--primary);
  animation: dotPulse 1.4s infinite ease-in-out;
}

.recommend-loading .dots span:nth-child(2) { animation-delay: 0.2s; }
.recommend-loading .dots span:nth-child(3) { animation-delay: 0.4s; }

@keyframes dotPulse {
  0%, 80%, 100% { opacity: 0.3; transform: scale(0.8); }
  40% { opacity: 1; transform: scale(1.2); }
}

.recommend-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.recommend-item {
  display: flex;
  gap: 10px;
  padding: 10px;
  background: white;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.recommend-item:hover {
  box-shadow: 0 4px 12px var(--shadow);
}

.recommend-item img {
  width: 60px;
  height: 60px;
  border-radius: 6px;
  object-fit: cover;
  flex-shrink: 0;
}

.recommend-item-info h4 {
  font-size: 0.83rem;
  font-weight: 600;
  line-height: 1.3;
  margin-bottom: 4px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.recommend-item-info span {
  font-size: 0.72rem;
  color: var(--text-muted);
}

/* ============================================
   专题推荐横滑
   ============================================ */
.topic-scroll {
  margin-bottom: 40px;
}

.topic-scroll-inner {
  display: flex;
  gap: 16px;
  overflow-x: auto;
  padding-bottom: 10px;
  scroll-snap-type: x mandatory;
}

.topic-scroll-inner::-webkit-scrollbar {
  height: 4px;
}

.topic-scroll-inner::-webkit-scrollbar-thumb {
  background: var(--accent);
  border-radius: 2px;
}

.topic-card {
  min-width: 280px;
  border-radius: var(--radius);
  overflow: hidden;
  position: relative;
  scroll-snap-align: start;
  flex-shrink: 0;
}

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

.topic-card-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(0,0,0,0.7), transparent);
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  padding: 16px;
  color: white;
}

.topic-card-overlay h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.topic-card-overlay span {
  font-size: 0.75rem;
  opacity: 0.8;
}

/* ============================================
   内容质量评分
   ============================================ */
.quality-score {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  background: var(--card-bg);
  border-radius: var(--radius-sm);
  margin-bottom: 20px;
}

.quality-score-num {
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--primary);
}

.quality-score-label {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.quality-bar {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.quality-bar-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.72rem;
}

.quality-bar-item span {
  width: 40px;
  color: var(--text-muted);
}

.quality-bar-item .bar {
  flex: 1;
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  overflow: hidden;
}

.quality-bar-item .bar-fill {
  height: 100%;
  background: var(--primary);
  border-radius: 2px;
  transition: width 0.6s ease;
}

/* ============================================
   阅读时长标签
   ============================================ */
.reading-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 10px;
  background: var(--card-bg);
  border-radius: 12px;
  font-size: 0.75rem;
  color: var(--primary);
  font-weight: 500;
}

/* ============================================
   页脚
   ============================================ */
.footer {
  background: #1A1A1A;
  color: #CCCCCC;
  padding: 50px 20px 30px;
  margin-top: 60px;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
}

.footer-brand p {
  font-size: 0.85rem;
  line-height: 1.7;
  margin-top: 12px;
  color: #999;
}

.footer-links h4 {
  font-size: 0.95rem;
  color: white;
  margin-bottom: 14px;
  font-weight: 600;
}

.footer-links a {
  display: block;
  font-size: 0.83rem;
  color: #999;
  margin-bottom: 8px;
}

.footer-links a:hover {
  color: var(--accent);
}

.footer-bottom {
  max-width: var(--max-width);
  margin: 30px auto 0;
  padding-top: 20px;
  border-top: 1px solid #333;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.78rem;
  color: #777;
}

.footer-social {
  display: flex;
  gap: 12px;
}

.footer-social a {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: #333;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #999;
  transition: var(--transition);
}

.footer-social a:hover {
  background: var(--primary);
  color: white;
}

/* ============================================
   面包屑
   ============================================ */
.breadcrumb {
  max-width: var(--max-width);
  margin: calc(var(--header-height) + 20px) auto 20px;
  padding: 0 20px;
  font-size: 0.83rem;
  color: var(--text-muted);
}

.breadcrumb a {
  color: var(--text-muted);
}

.breadcrumb a:hover {
  color: var(--primary);
}

.breadcrumb span {
  margin: 0 6px;
}

/* ============================================
   通用页面容器
   ============================================ */
.page-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

.page-header {
  text-align: center;
  padding: 40px 0;
}

.page-header h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.page-header p {
  font-size: 1rem;
  color: var(--text-light);
  max-width: 600px;
  margin: 0 auto;
}

/* ============================================
   搜索页
   ============================================ */
.search-page-box {
  max-width: 700px;
  margin: 0 auto 40px;
  display: flex;
  gap: 12px;
}

.search-page-box input {
  flex: 1;
  padding: 14px 20px;
  border: 2px solid var(--border);
  border-radius: 28px;
  font-size: 1rem;
  outline: none;
  transition: var(--transition);
}

.search-page-box input:focus {
  border-color: var(--primary);
}

.search-page-box button {
  padding: 14px 32px;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 28px;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
}

.search-page-box button:hover {
  background: var(--secondary);
}

.search-filters {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
  margin-bottom: 30px;
}

.search-filters button {
  padding: 6px 16px;
  border: 1px solid var(--border);
  background: white;
  border-radius: 20px;
  font-size: 0.83rem;
  cursor: pointer;
  transition: var(--transition);
}

.search-filters button:hover,
.search-filters button.active {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

/* ============================================
   404页面
   ============================================ */
.error-page {
  text-align: center;
  padding: 80px 20px;
  margin-top: var(--header-height);
}

.error-page img {
  max-width: 360px;
  margin: 0 auto 30px;
}

.error-page h1 {
  font-size: 2.5rem;
  color: var(--primary);
  margin-bottom: 12px;
}

.error-page p {
  font-size: 1.1rem;
  color: var(--text-light);
  margin-bottom: 24px;
}

.error-page .btn-home {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  background: var(--primary);
  color: white;
  border-radius: 24px;
  font-weight: 500;
  transition: var(--transition);
}

.error-page .btn-home:hover {
  background: var(--secondary);
  transform: translateY(-2px);
}

/* ============================================
   APP下载页
   ============================================ */
.app-hero {
  margin-top: var(--header-height);
  padding: 60px 20px;
  background: linear-gradient(135deg, var(--card-bg) 0%, #B2DFDB 100%);
  text-align: center;
}

.app-hero h1 {
  font-size: 2.2rem;
  margin-bottom: 16px;
}

.app-hero p {
  font-size: 1.1rem;
  color: var(--text-light);
  max-width: 600px;
  margin: 0 auto 30px;
}

.app-buttons {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.app-buttons a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  background: var(--text);
  color: white;
  border-radius: 8px;
  font-weight: 500;
  transition: var(--transition);
}

.app-buttons a:hover {
  background: var(--primary);
  color: white;
}

.app-features {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  padding: 60px 20px;
  max-width: var(--max-width);
  margin: 0 auto;
}

.app-feature-item {
  text-align: center;
  padding: 24px;
  border-radius: var(--radius);
  background: var(--card-bg);
}

.app-feature-item .icon {
  width: 48px;
  height: 48px;
  background: var(--primary);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 12px;
  font-size: 1.4rem;
  color: white;
}

.app-feature-item h3 {
  font-size: 1rem;
  margin-bottom: 8px;
}

.app-feature-item p {
  font-size: 0.83rem;
  color: var(--text-light);
}

/* ============================================
   合规页面
   ============================================ */
.compliance-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 40px 20px;
}

.compliance-content h1 {
  font-size: 1.8rem;
  margin-bottom: 8px;
}

.compliance-content .update-date {
  font-size: 0.83rem;
  color: var(--text-muted);
  margin-bottom: 30px;
}

.compliance-content h2 {
  font-size: 1.3rem;
  margin-top: 30px;
  margin-bottom: 12px;
  padding-left: 12px;
  border-left: 3px solid var(--primary);
}

.compliance-content p {
  margin-bottom: 14px;
  font-size: 0.95rem;
  line-height: 1.8;
}

.compliance-content ul {
  margin-bottom: 14px;
  padding-left: 20px;
}

.compliance-content ul li {
  position: relative;
  padding-left: 16px;
  margin-bottom: 8px;
  font-size: 0.95rem;
  line-height: 1.7;
}

.compliance-content ul li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--primary);
}

/* ============================================
   时间轴布局
   ============================================ */
.timeline {
  position: relative;
  padding-left: 30px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 10px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--border);
}

.timeline-item {
  position: relative;
  margin-bottom: 30px;
  padding: 20px;
  background: var(--card-bg);
  border-radius: var(--radius);
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -25px;
  top: 24px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--primary);
  border: 3px solid white;
  box-shadow: 0 0 0 2px var(--primary);
}

.timeline-item .time {
  font-size: 0.78rem;
  color: var(--primary);
  font-weight: 600;
  margin-bottom: 6px;
}

.timeline-item h3 {
  font-size: 1rem;
  margin-bottom: 6px;
}

.timeline-item p {
  font-size: 0.85rem;
  color: var(--text-light);
}

/* ============================================
   收藏夹书签动画
   ============================================ */
.bookmark-toast {
  position: fixed;
  top: 80px;
  right: 20px;
  background: var(--primary);
  color: white;
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  transform: translateX(120%);
  transition: transform 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  z-index: 9999;
  box-shadow: 0 4px 20px rgba(38, 166, 154, 0.3);
}

.bookmark-toast.show {
  transform: translateX(0);
}

/* ============================================
   按钮通用
   ============================================ */
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 22px;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 24px;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
}

.btn-primary:hover {
  background: var(--secondary);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(38, 166, 154, 0.3);
}

.btn-outline {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 22px;
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
  border-radius: 24px;
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
}

.btn-outline:hover {
  background: var(--primary);
  color: white;
}

/* ============================================
   响应式设计
   ============================================ */
@media (max-width: 1024px) {
  .main-content {
    grid-template-columns: 1fr;
  }
  .sidebar {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
  }
  .footer-inner {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --header-height: 56px;
  }
  .nav-menu {
    display: none;
  }
  .mobile-menu-btn {
    display: block;
  }
  .carousel-slide {
    aspect-ratio: 16/9;
  }
  .carousel-overlay {
    padding: 30px;
  }
  .carousel-overlay h2 {
    font-size: 1.4rem;
  }
  .carousel-nav {
    display: none;
  }
  .card-grid {
    grid-template-columns: 1fr;
  }
  .sidebar {
    grid-template-columns: 1fr;
  }
  .footer-inner {
    grid-template-columns: 1fr;
    gap: 24px;
  }
  .footer-bottom {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }
  .app-features {
    grid-template-columns: repeat(2, 1fr);
  }
  .search-page-box {
    flex-direction: column;
  }
  .topic-card {
    min-width: 240px;
  }
}

@media (max-width: 480px) {
  .app-features {
    grid-template-columns: 1fr;
  }
  .page-header h1 {
    font-size: 1.5rem;
  }
}

/* ============================================
   动画关键帧
   ============================================ */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in-up {
  animation: fadeInUp 0.5s ease forwards;
}

/* 图片渐显 */
img[loading="lazy"] {
  opacity: 0;
  transition: opacity 0.4s ease;
}

img[loading="lazy"].loaded {
  opacity: 1;
}

/* ============================================
   PWA安装提示
   ============================================ */
.pwa-install-prompt {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%) translateY(120%);
  background: white;
  padding: 16px 24px;
  border-radius: var(--radius);
  box-shadow: 0 8px 32px var(--shadow);
  display: flex;
  align-items: center;
  gap: 16px;
  z-index: 9998;
  transition: transform 0.4s ease;
  border: 1px solid var(--border);
}

.pwa-install-prompt.show {
  transform: translateX(-50%) translateY(0);
}

.pwa-install-prompt p {
  font-size: 0.9rem;
}

.pwa-install-prompt .btn-install {
  padding: 8px 16px;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 20px;
  font-size: 0.83rem;
  cursor: pointer;
  white-space: nowrap;
}

.pwa-install-prompt .btn-close {
  background: none;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  color: var(--text-muted);
}