/* ============================================
   移动优先信息流门户 - 主样式表
   暗色高级感 · 卡片化布局 · 移动端优先
   ============================================ */

:root {
  --color-primary: #6c5ce7;
  --color-primary-light: #a29bfe;
  --color-secondary: #00cec9;
  --color-accent: #fd79a8;
  --color-warning: #fdcb6e;
  --color-success: #00b894;
  --color-danger: #d63031;
  --color-bg: #0d1117;
  --color-bg-secondary: #161b22;
  --color-bg-card: #1c2128;
  --color-bg-elevated: #21262d;
  --color-text: #e6edf3;
  --color-text-secondary: #8b949e;
  --color-text-muted: #6e7681;
  --color-border: #30363d;
  --color-border-light: #21262d;
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.5);
  --shadow-glow: 0 0 20px rgba(108,92,231,0.3);
  --transition-fast: 0.15s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  --font-sans: -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-mono: "SF Mono", "Fira Code", monospace;
  --max-width: 768px;
  --bottom-nav-height: 60px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  min-height: 100vh;
  padding-bottom: var(--bottom-nav-height);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

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

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

ul, ol {
  list-style: none;
}

/* 容器 */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* 顶部导航栏 */
.top-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13,17,23,0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  padding: var(--spacing-sm) var(--spacing-md);
}

.top-header .header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
}

.top-header .logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
}

.top-header .logo img {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
}

.top-header .header-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.btn-search-trigger {
  background: none;
  border: none;
  color: var(--color-text-secondary);
  font-size: 1.2rem;
  cursor: pointer;
  padding: var(--spacing-xs);
  transition: color var(--transition-fast);
}

.btn-search-trigger:hover {
  color: var(--color-primary-light);
}

/* PWA安装条 */
.pwa-install-bar {
  display: none;
  background: linear-gradient(135deg, var(--color-primary), #4834d4);
  padding: var(--spacing-sm) var(--spacing-md);
  text-align: center;
  font-size: 0.85rem;
  color: #fff;
  position: relative;
  animation: slideDown 0.4s ease;
}

.pwa-install-bar.show {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
}

.pwa-install-bar .btn-install {
  background: rgba(255,255,255,0.2);
  border: 1px solid rgba(255,255,255,0.4);
  color: #fff;
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  cursor: pointer;
  transition: background var(--transition-fast);
}

.pwa-install-bar .btn-install:hover {
  background: rgba(255,255,255,0.3);
}

.pwa-install-bar .btn-close-pwa {
  position: absolute;
  right: var(--spacing-md);
  background: none;
  border: none;
  color: rgba(255,255,255,0.7);
  font-size: 1.2rem;
  cursor: pointer;
}

@keyframes slideDown {
  from { transform: translateY(-100%); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

/* 首屏英雄区 */
.hero-section {
  position: relative;
  padding: var(--spacing-xl) var(--spacing-md);
  text-align: center;
  overflow: hidden;
}

.hero-section::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, transparent, var(--color-bg));
  z-index: 1;
}

.hero-section .hero-bg {
  position: absolute;
  inset: 0;
  object-fit: cover;
  width: 100%;
  height: 100%;
  opacity: 0.3;
}

.hero-section .hero-content {
  position: relative;
  z-index: 2;
}

.hero-section h1 {
  font-size: 1.8rem;
  font-weight: 800;
  margin-bottom: var(--spacing-sm);
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-section .hero-subtitle {
  font-size: 0.95rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-lg);
  line-height: 1.6;
}

/* 搜索框 */
.search-box {
  position: relative;
  max-width: 480px;
  margin: 0 auto var(--spacing-lg);
}

.search-box input {
  width: 100%;
  padding: 12px 44px 12px 16px;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  color: var(--color-text);
  font-size: 0.9rem;
  outline: none;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

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

.search-box input::placeholder {
  color: var(--color-text-muted);
}

.search-box .search-btn {
  position: absolute;
  right: 4px;
  top: 50%;
  transform: translateY(-50%);
  background: var(--color-primary);
  border: none;
  color: #fff;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition-fast);
}

.search-box .search-btn:hover {
  background: var(--color-primary-light);
}

/* 搜索建议 */
.search-suggestions {
  display: none;
  position: absolute;
  top: calc(100% + 4px);
  left: 0;
  right: 0;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  z-index: 50;
  max-height: 240px;
  overflow-y: auto;
}

.search-suggestions.active {
  display: block;
}

.search-suggestions .suggestion-item {
  padding: 10px 16px;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: background var(--transition-fast);
  border-bottom: 1px solid var(--color-border-light);
}

.search-suggestions .suggestion-item:last-child {
  border-bottom: none;
}

.search-suggestions .suggestion-item:hover {
  background: var(--color-bg-elevated);
  color: var(--color-text);
}

/* 栏目标签切换 */
.tab-nav {
  display: flex;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-md);
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
  border-bottom: 1px solid var(--color-border);
}

.tab-nav::-webkit-scrollbar {
  display: none;
}

.tab-nav .tab-item {
  flex-shrink: 0;
  padding: 6px 16px;
  border-radius: var(--radius-xl);
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  background: transparent;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.tab-nav .tab-item.active,
.tab-nav .tab-item:hover {
  color: var(--color-primary-light);
  background: rgba(108,92,231,0.1);
  border-color: rgba(108,92,231,0.3);
}

/* 信息流卡片 */
.feed-section {
  padding: var(--spacing-md);
}

.feed-section .section-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.feed-section .section-title::before {
  content: '';
  width: 3px;
  height: 18px;
  background: var(--color-primary);
  border-radius: 2px;
}

.card-feed {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.card-item {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.card-item:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.card-item .card-image {
  position: relative;
  width: 100%;
  aspect-ratio: 16/9;
  overflow: hidden;
}

.card-item .card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

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

.card-item .card-tag {
  position: absolute;
  top: var(--spacing-sm);
  left: var(--spacing-sm);
  background: rgba(108,92,231,0.9);
  color: #fff;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  font-size: 0.7rem;
  font-weight: 600;
}

.card-item .card-body {
  padding: var(--spacing-md);
}

.card-item .card-title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-item .card-desc {
  font-size: 0.82rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: var(--spacing-sm);
}

.card-item .card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

/* 横向滚动卡片 */
.scroll-cards {
  display: flex;
  gap: var(--spacing-md);
  overflow-x: auto;
  padding: var(--spacing-sm) 0;
  scrollbar-width: none;
  -ms-overflow-style: none;
}

.scroll-cards::-webkit-scrollbar {
  display: none;
}

.scroll-card-item {
  flex-shrink: 0;
  width: 200px;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: transform var(--transition-fast);
}

.scroll-card-item:hover {
  transform: scale(1.02);
}

.scroll-card-item img {
  width: 100%;
  aspect-ratio: 3/2;
  object-fit: cover;
}

.scroll-card-item .scroll-card-title {
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: 0.82rem;
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* 榜单列表 */
.rank-list {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.rank-list .rank-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-md);
  border-bottom: 1px solid var(--color-border-light);
  transition: background var(--transition-fast);
}

.rank-list .rank-item:last-child {
  border-bottom: none;
}

.rank-list .rank-item:hover {
  background: var(--color-bg-elevated);
}

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

.rank-list .rank-item:nth-child(1) .rank-num {
  background: var(--color-danger);
  color: #fff;
}

.rank-list .rank-item:nth-child(2) .rank-num {
  background: var(--color-warning);
  color: #333;
}

.rank-list .rank-item:nth-child(3) .rank-num {
  background: var(--color-primary);
  color: #fff;
}

.rank-list .rank-title {
  flex: 1;
  font-size: 0.88rem;
  line-height: 1.4;
}

.rank-list .rank-heat {
  font-size: 0.72rem;
  color: var(--color-text-muted);
  flex-shrink: 0;
}

/* FAQ模块 */
.faq-section {
  padding: var(--spacing-lg) var(--spacing-md);
}

.faq-item {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-sm);
  overflow: hidden;
}

.faq-question {
  padding: var(--spacing-md);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: background var(--transition-fast);
}

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

.faq-question::after {
  content: '+';
  font-size: 1.2rem;
  color: var(--color-primary-light);
  transition: transform var(--transition-fast);
}

.faq-item.open .faq-question::after {
  content: '−';
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-normal);
}

.faq-item.open .faq-answer {
  max-height: 500px;
}

.faq-answer-inner {
  padding: 0 var(--spacing-md) var(--spacing-md);
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

/* 面包屑导航 */
.breadcrumb {
  padding: var(--spacing-md);
  font-size: 0.8rem;
  color: var(--color-text-muted);
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

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

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

/* 页面标题区 */
.page-header {
  padding: var(--spacing-lg) var(--spacing-md);
  border-bottom: 1px solid var(--color-border);
}

.page-header h1 {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: var(--spacing-sm);
}

.page-header .page-desc {
  font-size: 0.88rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

/* 底部导航 */
.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 200;
  background: rgba(13,17,23,0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-top: 1px solid var(--color-border);
  height: var(--bottom-nav-height);
  display: flex;
  align-items: center;
  justify-content: space-around;
  padding: 0 var(--spacing-sm);
}

.bottom-nav .nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: var(--spacing-xs) var(--spacing-sm);
  color: var(--color-text-muted);
  font-size: 0.65rem;
  text-decoration: none;
  transition: color var(--transition-fast);
  min-width: 48px;
}

.bottom-nav .nav-item .nav-icon {
  font-size: 1.3rem;
  line-height: 1;
}

.bottom-nav .nav-item.active,
.bottom-nav .nav-item:hover {
  color: var(--color-primary-light);
}

/* 浮动按钮 */
.fab-download {
  position: fixed;
  right: var(--spacing-md);
  bottom: calc(var(--bottom-nav-height) + var(--spacing-md));
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--color-primary), #4834d4);
  border: none;
  border-radius: 50%;
  color: #fff;
  font-size: 1.3rem;
  cursor: pointer;
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 150;
  transition: transform var(--transition-fast);
  text-decoration: none;
}

.fab-download:hover {
  transform: scale(1.1);
  color: #fff;
}

/* 返回顶部 */
.back-to-top {
  position: fixed;
  right: var(--spacing-md);
  bottom: calc(var(--bottom-nav-height) + 76px);
  width: 40px;
  height: 40px;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 50%;
  color: var(--color-text-secondary);
  font-size: 1rem;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 150;
  transition: all var(--transition-fast);
}

.back-to-top.show {
  display: flex;
}

.back-to-top:hover {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

/* 页脚 */
.site-footer {
  background: var(--color-bg-secondary);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-xl) var(--spacing-md) calc(var(--spacing-xl) + var(--bottom-nav-height));
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
  font-weight: 700;
  font-size: 1rem;
}

.footer-brand img {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-xl);
}

.footer-links .link-group h4 {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--spacing-sm);
}

.footer-links .link-group a {
  display: block;
  font-size: 0.78rem;
  color: var(--color-text-secondary);
  padding: 3px 0;
  transition: color var(--transition-fast);
}

.footer-links .link-group a:hover {
  color: var(--color-primary-light);
}

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-top: var(--spacing-md);
  font-size: 0.72rem;
  color: var(--color-text-muted);
  text-align: center;
  line-height: 1.8;
}

/* 通用按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: 10px 20px;
  border-radius: var(--radius-md);
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-primary-light);
  color: #fff;
}

.btn-outline {
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
}

.btn-outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary-light);
}

/* 提示条 */
.toast {
  position: fixed;
  top: 80px;
  left: 50%;
  transform: translateX(-50%) translateY(-20px);
  background: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: 0.85rem;
  color: var(--color-text);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-normal);
  z-index: 999;
}

.toast.show {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

/* 内容区通用 */
.content-section {
  padding: var(--spacing-lg) var(--spacing-md);
}

.content-section h2 {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: var(--spacing-md);
}

.content-section h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.content-section p {
  font-size: 0.88rem;
  color: var(--color-text-secondary);
  line-height: 1.8;
  margin-bottom: var(--spacing-md);
}

/* 合规提醒条 */
.compliance-notice {
  background: rgba(108,92,231,0.08);
  border: 1px solid rgba(108,92,231,0.2);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  margin: var(--spacing-lg) var(--spacing-md);
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.compliance-notice a {
  color: var(--color-primary-light);
}

/* 表单 */
.form-group {
  margin-bottom: var(--spacing-md);
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
  color: var(--color-text);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 10px 14px;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  color: var(--color-text);
  font-size: 0.88rem;
  outline: none;
  transition: border-color var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  border-color: var(--color-primary);
}

.form-group textarea {
  min-height: 120px;
  resize: vertical;
}

/* 时间线 */
.timeline {
  position: relative;
  padding-left: var(--spacing-lg);
}

.timeline::before {
  content: '';
  position: absolute;
  left: 8px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--color-border);
}

.timeline-item {
  position: relative;
  margin-bottom: var(--spacing-lg);
  padding-left: var(--spacing-md);
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -20px;
  top: 6px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--color-primary);
  border: 2px solid var(--color-bg);
}

.timeline-item .timeline-date {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  margin-bottom: var(--spacing-xs);
}

.timeline-item .timeline-content {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

/* 标签 */
.tag {
  display: inline-block;
  padding: 2px 10px;
  background: rgba(108,92,231,0.1);
  border: 1px solid rgba(108,92,231,0.2);
  border-radius: var(--radius-xl);
  font-size: 0.72rem;
  color: var(--color-primary-light);
  margin: 2px;
}

/* 响应式 - 平板及桌面 */
@media (min-width: 768px) {
  :root {
    --max-width: 960px;
  }

  .hero-section h1 {
    font-size: 2.4rem;
  }

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

  .footer-links {
    grid-template-columns: repeat(4, 1fr);
  }

  .bottom-nav {
    max-width: 480px;
    left: 50%;
    transform: translateX(-50%);
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
  }
}

@media (min-width: 1024px) {
  :root {
    --max-width: 1080px;
  }

  body {
    padding-bottom: 0;
  }

  .bottom-nav {
    display: none;
  }

  .fab-download {
    bottom: var(--spacing-xl);
  }

  .back-to-top {
    bottom: calc(var(--spacing-xl) + 60px);
  }

  .site-footer {
    padding-bottom: var(--spacing-xl);
  }
}

/* 动画 */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-in {
  animation: fadeInUp 0.4s ease forwards;
}

/* 加载骨架屏 */
.skeleton {
  background: linear-gradient(90deg, var(--color-bg-card) 25%, var(--color-bg-elevated) 50%, var(--color-bg-card) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--radius-sm);
}

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