/* ==========================================================================
   博客公共样式 common.css
   说明：包含 CSS 变量、全局重置、导航栏、底部、通用组件、主题切换
   主色调：莫兰迪蓝灰 #64748B
   ========================================================================== */

/* ---------- CSS 变量：日间模式（默认） ---------- */
:root {
  /* 主色系 */
  --color-primary: #64748B;          /* 主色：莫兰迪蓝灰 */
  --color-primary-hover: #475569;    /* 主色悬停：加深 */
  --color-primary-light: #F1F5F9;    /* 主色浅底：卡片底/标签底 */
  --color-accent: #0EA5E9;           /* 强调点缀：新/热小标签 */

  /* 文字 */
  --color-text: #1E293B;             /* 正文 */
  --color-text-secondary: #64748B;   /* 次要文字：时间/摘要 */
  --color-text-light: #94A3B8;       /* 更弱的文字：占位/提示 */

  /* 背景 */
  --color-bg: #FFFFFF;               /* 页面背景 */
  --color-bg-card: #FFFFFF;          /* 卡片背景 */
  --color-bg-hover: #F8FAFC;         /* hover 背景 */
  --color-bg-code: #F1F5F9;          /* 行内代码背景 */

  /* 边框 */
  --color-border: #E2E8F0;           /* 普通边框 */
  --color-border-light: #F1F5F9;     /* 浅边框 */

  /* 阴影 */
  --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.06);   /* 卡片阴影 */
  --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.10); /* hover 阴影 */

  /* 圆角 */
  --radius-sm: 4px;
  --radius: 8px;       /* 统一圆角 */
  --radius-lg: 12px;

  /* 间距 */
  --container-width: 1200px;         /* 内容区最大宽度 */
  --header-height: 64px;             /* 导航栏高度 */

  /* 字体 */
  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "Fira Code", Consolas, Monaco, monospace;
}

/* ---------- CSS 变量：夜间模式 ---------- */
body.theme-dark {
  --color-primary: #94A3B8;
  --color-primary-hover: #CBD5E1;
  --color-primary-light: #1E293B;
  --color-accent: #38BDF8;

  --color-text: #E2E8F0;
  --color-text-secondary: #94A3B8;
  --color-text-light: #64748B;

  --color-bg: #0F172A;
  --color-bg-card: #1E293B;
  --color-bg-hover: #334155;
  --color-bg-code: #334155;

  --color-border: #334155;
  --color-border-light: #1E293B;

  --shadow-card: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.4);
}

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

html {
  scroll-behavior: smooth;  /* 锚点跳转平滑 */
}

body {
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: background-color 0.3s, color 0.3s;  /* 主题切换过渡 */
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s;
}

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

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

ul, ol {
  list-style: none;
}

/* 滚动条美化 */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--color-text-light);
}

/* ==========================================================================
   通用布局类
   ========================================================================== */

/* 内容容器：居中 + 最大宽度 */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* 主内容 + 侧边栏 双栏布局 */
.layout-main {
  display: flex;
  gap: 30px;
  padding: 30px 0;
}
.layout-content {
  flex: 1;
  min-width: 0;  /* 防止 flex 子项溢出 */
}
.layout-sidebar {
  width: 300px;
  flex-shrink: 0;
  position: sticky;        /* 侧边栏粘性定位：滚动时跟随，避免列表比侧边栏长时出现大片空白 */
  top: calc(var(--header-height) + 20px);  /* 顶部留出导航栏高度 + 间距 */
  align-self: flex-start;  /* sticky 生效关键：让侧边栏在交叉轴顶部对齐 */
}

/* ==========================================================================
   导航栏
   ========================================================================== */
.header {
  position: sticky;          /* 粘性定位：滚动时固定顶部 */
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  transition: background-color 0.3s;
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 20px;
  font-weight: 700;
  color: var(--color-text);
}
.logo:hover {
  color: var(--color-primary);
}
.logo-icon {
  width: 32px;
  height: 32px;
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
}

/* 主菜单 */
.nav-menu {
  display: flex;
  align-items: center;
  gap: 4px;
}
.nav-menu a {
  padding: 8px 14px;
  color: var(--color-text-secondary);
  font-size: 15px;
  border-radius: var(--radius-sm);
  transition: all 0.2s;
}
.nav-menu a:hover {
  color: var(--color-primary);
  background: var(--color-primary-light);
}
.nav-menu a.active {
  color: var(--color-primary);
  background: var(--color-primary-light);
  font-weight: 500;
}

/* 右侧操作区 */
.nav-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}
.nav-actions .icon-btn {
  width: 36px;
  height: 36px;
  border: none;
  background: transparent;
  color: var(--color-text-secondary);
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  transition: all 0.2s;
}
.nav-actions .icon-btn:hover {
  color: var(--color-primary);
  background: var(--color-primary-light);
}

/* 移动端汉堡菜单按钮（默认隐藏） */
.menu-toggle {
  display: none;
  width: 36px;
  height: 36px;
  border: none;
  background: transparent;
  color: var(--color-text);
  font-size: 22px;
  cursor: pointer;
}

/* ==========================================================================
   底部
   ========================================================================== */
.footer {
  background: var(--color-bg-card);
  border-top: 1px solid var(--color-border);
  padding: 40px 0 20px;
  margin-top: 60px;
}
.footer-inner {
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 14px;
}
.footer-links {
  margin-bottom: 12px;
}
.footer-links a {
  margin: 0 10px;
  color: var(--color-text-secondary);
}
.footer-info p {
  margin: 4px 0;
}
.footer-info a {
  color: var(--color-text-secondary);
}

/* ==========================================================================
   通用组件
   ========================================================================== */

/* 卡片 */
.card {
  background: var(--color-bg-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  transition: box-shadow 0.2s, transform 0.2s;
}
.card-hover:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}

/* 文章卡片 */
.article-card {
  display: flex;
  gap: 20px;
  padding: 20px;
  margin-bottom: 20px;
  background: var(--color-bg-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  transition: box-shadow 0.2s, transform 0.2s;
  cursor: pointer;
}
.article-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}
.article-card .cover {
  width: 200px;
  height: 130px;
  border-radius: var(--radius);
  object-fit: cover;
  flex-shrink: 0;
}
.article-card .info {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}
.article-card .title {
  font-size: 18px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 8px;
  /* 单行省略 */
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.article-card .excerpt {
  font-size: 14px;
  color: var(--color-text-secondary);
  line-height: 1.6;
  /* 两行省略 */
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: 12px;
}
.article-card .meta {
  display: flex;
  align-items: center;
  gap: 14px;
  font-size: 13px;
  color: var(--color-text-light);
  margin-top: auto;  /* 推到底部 */
}
.article-card .meta span {
  display: flex;
  align-items: center;
  gap: 4px;
}

/* 标签 */
.tag {
  display: inline-block;
  padding: 2px 10px;
  font-size: 12px;
  color: var(--color-primary);
  background: var(--color-primary-light);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.2s;
}
.tag:hover {
  color: #fff;
  background: var(--color-primary);
}

/* 侧边栏卡片 */
.sidebar-card {
  padding: 20px;
  margin-bottom: 20px;
  background: var(--color-bg-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
}
.sidebar-card .card-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--color-border-light);
  display: flex;
  align-items: center;
  gap: 8px;
}

/* 个人简介卡 */
.profile-card .avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  margin: 0 auto 12px;
  object-fit: cover;
  border: 3px solid var(--color-primary-light);
}
.profile-card .name {
  text-align: center;
  font-size: 18px;
  font-weight: 600;
  color: var(--color-text);
}
.profile-card .bio {
  text-align: center;
  font-size: 13px;
  color: var(--color-text-secondary);
  margin: 8px 0 16px;
}
.profile-card .social {
  display: flex;
  justify-content: center;
  gap: 12px;
}
.profile-card .social a {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-primary-light);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  transition: all 0.2s;
}
.profile-card .social a:hover {
  background: var(--color-primary);
  color: #fff;
}

/* 热门文章列表 */
.hot-list li {
  padding: 8px 0;
  display: flex;
  align-items: center;
  gap: 10px;
  border-bottom: 1px dashed var(--color-border-light);
}
.hot-list li:last-child {
  border-bottom: none;
}
.hot-list .rank {
  width: 20px;
  height: 20px;
  border-radius: 4px;
  background: var(--color-primary-light);
  color: var(--color-text-secondary);
  font-size: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.hot-list li:nth-child(1) .rank {
  background: #FEF3C7;
  color: #D97706;
}
.hot-list li:nth-child(2) .rank {
  background: #E0E7FF;
  color: #4F46E5;
}
.hot-list li:nth-child(3) .rank {
  background: #FEE2E2;
  color: #DC2626;
}
.hot-list .title {
  flex: 1;
  font-size: 13px;
  color: var(--color-text);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  cursor: pointer;
}
.hot-list .title:hover {
  color: var(--color-primary);
}

/* 标签云 */
.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.tag-cloud .tag {
  font-size: 12px;
}
.tag-cloud .tag.size-sm { font-size: 11px; }
.tag-cloud .tag.size-md { font-size: 13px; }
.tag-cloud .tag.size-lg { font-size: 15px; }

/* 分类目录列表 */
.category-list li {
  padding: 8px 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px dashed var(--color-border-light);
  cursor: pointer;
}
.category-list li:last-child { border-bottom: none; }
.category-list .name:hover { color: var(--color-primary); }
.category-list .count {
  font-size: 12px;
  color: var(--color-text-light);
  background: var(--color-primary-light);
  padding: 1px 8px;
  border-radius: 10px;
}

/* 分页器 */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 6px;
  margin: 40px 0;
}
.pagination a, .pagination span {
  min-width: 36px;
  height: 36px;
  padding: 0 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text-secondary);
  font-size: 14px;
  cursor: pointer;
  transition: all 0.2s;
}
.pagination a:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
}
.pagination .current {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

/* 返回顶部按钮 */
.back-to-top {
  position: fixed;
  right: 30px;
  bottom: 30px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  border: none;
  font-size: 20px;
  cursor: pointer;
  box-shadow: var(--shadow-hover);
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s;
  z-index: 99;
}
.back-to-top.show {
  opacity: 1;
  visibility: visible;
}
.back-to-top:hover {
  background: var(--color-primary-hover);
  transform: translateY(-2px);
}

/* 骨架屏（加载占位） */
.skeleton {
  background: linear-gradient(90deg, var(--color-primary-light) 25%, var(--color-bg-hover) 50%, var(--color-primary-light) 75%);
  background-size: 200% 100%;
  animation: skeleton-loading 1.5s infinite;
  border-radius: var(--radius-sm);
}
@keyframes skeleton-loading {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* 空状态 */
.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--color-text-light);
}
.empty-state .icon {
  font-size: 48px;
  margin-bottom: 12px;
}

/* 页面标题 */
.page-header {
  padding: 30px 0;
  text-align: center;
}
.page-header h1 {
  font-size: 28px;
  color: var(--color-text);
  margin-bottom: 8px;
}
.page-header .subtitle {
  color: var(--color-text-secondary);
  font-size: 14px;
}

/* 列表页通栏标题区（与 .hero 类似的渐变背景，用于文章/专栏/标签/归档/友链/关于等列表页） */
.page-banner {
  text-align: center;
  padding: 40px 20px 30px;
  background: linear-gradient(180deg, var(--color-primary-light) 0%, var(--color-bg) 100%);
}
.page-banner h1 {
  font-size: 28px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 8px;
}
.page-banner .subtitle {
  font-size: 14px;
  color: var(--color-text-secondary);
}

/* ==========================================================================
   响应式：移动端适配
   ========================================================================== */
@media (max-width: 1024px) {
  .layout-sidebar {
    width: 260px;
  }
  .article-card .cover {
    width: 160px;
    height: 110px;
  }
}

@media (max-width: 768px) {
  /* 隐藏主菜单，显示汉堡按钮 */
  .nav-menu {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    align-items: stretch;
    padding: 10px;
    gap: 4px;
    transform: translateY(-150%);  /* 默认收起 */
    transition: transform 0.3s;
    z-index: 99;
  }
  .nav-menu.show {
    transform: translateY(0);
  }
  .menu-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
  }

  /* 双栏改单栏 */
  .layout-main {
    flex-direction: column;
  }
  .layout-sidebar {
    width: 100%;
    position: static;        /* 移动端取消 sticky，避免悬浮遮挡内容 */
    max-height: none;        /* 高度不限制 */
    overflow-y: visible;
  }

  /* 文章卡片改纵向 */
  .article-card {
    flex-direction: column;
  }
  .article-card .cover {
    width: 100%;
    height: 180px;
  }

  .back-to-top {
    right: 20px;
    bottom: 20px;
  }
}