/* ============================================
   自定义样式 - 宋家强 博客优化
   ============================================ */

/* 色彩系统 - 浅色主题 */
:root {
  --primary-color: #1e88e5;
  --secondary-color: #43a047;
  --bg-color: #ffffff;
  --card-bg: #f5f5f5;
  --text-primary: #212121;
  --text-secondary: #757575;
  --border-color: #e0e0e0;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.15);
}

/* 色彩系统 - 暗色主题 */
[data-theme="dark"] {
  --primary-color: #42a5f5;
  --secondary-color: #66bb6a;
  --bg-color: #121212;
  --card-bg: #1e1e1e;
  --text-primary: #e0e0e0;
  --text-secondary: #9e9e9e;
  --border-color: #333333;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.4);
}

/* 排版规范 */
:root {
  --font-heading-zh: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-heading-en: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-body-zh: "Songti SC", "STSong", "SimSun", serif;
  --font-body-en: Georgia, "Times New Roman", serif;
  --font-code: "JetBrains Mono", "Fira Code", "Consolas", monospace;
  
  --h1-size: 2.5rem; /* 40px */
  --h2-size: 2rem;   /* 32px */
  --h3-size: 1.5rem; /* 24px */
  --body-size: 1rem; /* 16px */
  --small-size: 0.875rem; /* 14px */
}

/* 间距系统 */
:root {
  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 24px;
  --spacing-lg: 48px;
}

/* Hero Section */
.hero-section {
  position: relative;
  width: 100%;
  min-height: 400px;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--spacing-lg) var(--spacing-sm);
  background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
  margin-bottom: var(--spacing-lg);
  border-radius: 12px;
  overflow: hidden;
}

[data-theme="dark"] .hero-section {
  background: linear-gradient(135deg, #1e3a5f 0%, #2d4a2f 100%);
}

.hero-section::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><defs><pattern id="grid" width="100" height="100" patternUnits="userSpaceOnUse"><path d="M 100 0 L 0 0 0 100" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="1"/></pattern></defs><rect width="100%" height="100%" fill="url(%23grid)"/></svg>');
  opacity: 0.3;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
  margin: 0 auto;
}

.hero-title {
  font-size: clamp(2rem, 5vw, var(--h1-size));
  font-weight: 700;
  color: #ffffff;
  margin-bottom: var(--spacing-sm);
  font-family: var(--font-heading-zh), var(--font-heading-en);
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.hero-subtitle {
  font-size: clamp(1rem, 2.5vw, 1.25rem);
  color: rgba(255, 255, 255, 0.9);
  margin-bottom: var(--spacing-md);
  font-family: var(--font-body-zh), var(--font-body-en);
  line-height: 1.6;
}

.hero-buttons {
  display: flex;
  gap: var(--spacing-sm);
  justify-content: center;
  flex-wrap: wrap;
  margin-top: var(--spacing-md);
}

.hero-button {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  font-size: var(--body-size);
  font-weight: 500;
  color: var(--primary-color);
  background: #ffffff;
  border: none;
  border-radius: 8px;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.hero-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
  color: var(--primary-color);
}

.hero-button.secondary {
  background: rgba(255, 255, 255, 0.2);
  color: #ffffff;
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.hero-button.secondary:hover {
  background: rgba(255, 255, 255, 0.3);
  color: #ffffff;
}

/* 优化的文章卡片 */
.post-card {
  background: var(--card-bg);
  border-radius: 12px;
  overflow: hidden;
  transition: all 0.3s ease;
  box-shadow: var(--shadow);
  margin-bottom: var(--spacing-md);
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border-color);
}

.post-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.post-card-image {
  width: 100%;
  height: 200px;
  object-fit: cover;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  display: block;
}

.post-card-content {
  padding: var(--spacing-sm);
  flex: 1;
  display: flex;
  flex-direction: column;
}

.post-card-header {
  margin-bottom: var(--spacing-xs);
}

.post-card-title {
  font-size: var(--h3-size);
  font-weight: 600;
  margin: 0 0 var(--spacing-xs) 0;
  color: var(--text-primary);
  font-family: var(--font-heading-zh), var(--font-heading-en);
}

.post-card-title a {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s;
}

.post-card-title a:hover {
  color: var(--primary-color);
}

.post-card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  font-size: var(--small-size);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xs);
}

.post-card-summary {
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: var(--spacing-sm);
  flex: 1;
  font-family: var(--font-body-zh), var(--font-body-en);
}

.post-card-footer {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  align-items: center;
  justify-content: space-between;
  padding-top: var(--spacing-xs);
  border-top: 1px solid var(--border-color);
}

.post-card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.tag-badge {
  display: inline-block;
  padding: 4px 8px;
  font-size: 0.75rem;
  background: var(--primary-color);
  color: #ffffff;
  border-radius: 4px;
  text-decoration: none;
  transition: all 0.2s;
}

.tag-badge:hover {
  background: var(--secondary-color);
  transform: scale(1.05);
}

.category-badge {
  display: inline-block;
  padding: 4px 8px;
  font-size: 0.75rem;
  background: var(--secondary-color);
  color: #ffffff;
  border-radius: 4px;
  text-decoration: none;
  transition: all 0.2s;
}

.category-badge:hover {
  background: var(--primary-color);
  transform: scale(1.05);
}

.post-card-read-more {
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 500;
  font-size: var(--small-size);
  transition: all 0.2s;
}

.post-card-read-more:hover {
  color: var(--secondary-color);
  text-decoration: underline;
}

/* 文章网格布局 */
.posts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-md);
}

@media (max-width: 768px) {
  .posts-grid {
    grid-template-columns: 1fr;
  }
}

/* 内容分区 */
.content-section {
  margin-bottom: var(--spacing-lg);
}

.section-title {
  font-size: var(--h2-size);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
  font-family: var(--font-heading-zh), var(--font-heading-en);
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.section-title::after {
  content: '';
  flex: 1;
  height: 2px;
  background: linear-gradient(to right, var(--primary-color), transparent);
}

/* 优化的导航栏 */
.nav {
  backdrop-filter: blur(10px);
  background: rgba(var(--bg-color-rgb, 255, 255, 255), 0.9);
}

[data-theme="dark"] .nav {
  background: rgba(var(--bg-color-rgb, 18, 18, 18), 0.9);
}

/* =====================
   文档布局 — 精工纸张美学
   ===================== */

:root {
  --sidebar-w: 252px;
  --sidebar-bg-light: #faf9f6;
  --sidebar-border-light: #d8d3c8;
  --sidebar-ink: #2c2c2c;
  --sidebar-ink-muted: #7a756e;
  --sidebar-accent: #1a4a7a;
  --sidebar-highlight: rgba(252, 228, 150, 0.55);
  --sidebar-highlight-border: #d4a80a;
  --sidebar-active-text: #0f2f52;
  --sidebar-font: 'Noto Serif SC', 'Songti SC', 'STSong', Georgia, serif;
}

[data-theme="dark"] {
  --sidebar-bg-light: #18181a;
  --sidebar-border-light: #2e2e32;
  --sidebar-ink: #d8d4cc;
  --sidebar-ink-muted: #7a7870;
  --sidebar-accent: #5b9bd5;
  --sidebar-highlight: rgba(180, 140, 40, 0.18);
  --sidebar-highlight-border: #c09a20;
  --sidebar-active-text: #8ec4f0;
}

.doc-layout {
  display: flex;
  align-items: flex-start;
  width: 100%;
  padding: 0;
  gap: 0;
}

/* ── 左侧侧边栏 ── */
.doc-sidebar {
  position: sticky;
  top: 52px;
  width: var(--sidebar-w);
  min-width: var(--sidebar-w);
  max-height: calc(100vh - 60px);
  overflow: hidden;
  flex-shrink: 0;
  background: var(--sidebar-bg-light);
  border-right: 1px solid var(--sidebar-border-light);
  display: flex;
  flex-direction: column;
  transition: width 0.22s cubic-bezier(.4,0,.2,1),
              min-width 0.22s cubic-bezier(.4,0,.2,1);
}

.doc-sidebar.is-collapsed {
  width: 42px;
  min-width: 42px;
}

.doc-sidebar.is-collapsed .sidebar-nav,
.doc-sidebar.is-collapsed .sidebar-fade-bottom,
.doc-sidebar.is-collapsed .sidebar-title {
  opacity: 0;
  pointer-events: none;
}

/* ── 头部 ── */
.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 16px 12px;
  border-bottom: 1px solid var(--sidebar-border-light);
  flex-shrink: 0;
}

.sidebar-title {
  display: flex;
  align-items: center;
  gap: 7px;
  font-family: var(--sidebar-font);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--sidebar-ink-muted);
  transition: opacity 0.18s;
}

.sidebar-icon {
  opacity: 0.6;
  flex-shrink: 0;
}

.sidebar-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  border: 1px solid var(--sidebar-border-light);
  background: transparent;
  color: var(--sidebar-ink-muted);
  cursor: pointer;
  border-radius: 5px;
  padding: 0;
  flex-shrink: 0;
  transition: border-color 0.15s, color 0.15s, background 0.15s;
}

.sidebar-toggle:hover {
  border-color: var(--sidebar-accent);
  color: var(--sidebar-accent);
  background: color-mix(in srgb, var(--sidebar-accent) 6%, transparent);
}

.doc-sidebar.is-collapsed .sidebar-header {
  justify-content: center;
  padding: 18px 8px 12px;
}

/* ── 导航树 ── */
.sidebar-nav {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 10px 10px 40px;
  scrollbar-width: thin;
  scrollbar-color: var(--sidebar-border-light) transparent;
  scroll-behavior: smooth;
  width: 100%;
}

.sidebar-nav > nav {
  width: 100%;
  overflow: hidden;
}

.sidebar-nav::-webkit-scrollbar { width: 3px; }
.sidebar-nav::-webkit-scrollbar-thumb {
  background: var(--sidebar-border-light);
  border-radius: 2px;
}

.sidebar-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.sidebar-nav li {
  margin: 0;
  line-height: 1;
}

/* H1 层 — 穿透 nav#TableOfContents */
.sidebar-nav li > a {
  display: block;
  padding: 6px 10px;
  font-family: var(--sidebar-font);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--sidebar-ink);
  text-decoration: none;
  border-radius: 4px;
  line-height: 1.55;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  transition: background 0.14s, color 0.14s;
  position: relative;
}

/* H2 层 */
.sidebar-nav ul ul > li > a {
  padding: 5px 10px 5px 20px;
  font-size: 0.78rem;
  font-weight: 400;
  color: var(--sidebar-ink-muted);
}

/* H3 层 */
.sidebar-nav ul ul ul > li > a {
  padding: 4px 10px 4px 32px;
  font-size: 0.73rem;
  font-weight: 400;
  color: var(--sidebar-ink-muted);
  opacity: 0.8;
}

.sidebar-nav a:hover {
  color: var(--sidebar-accent);
  background: color-mix(in srgb, var(--sidebar-accent) 7%, transparent);
  text-decoration: none;
  opacity: 1;
}

/* ── 激活态：荧光笔效果 ── */
.sidebar-nav a.active {
  color: var(--sidebar-active-text) !important;
  font-weight: 600;
  opacity: 1;
  background: var(--sidebar-highlight);
  border-left: 2.5px solid var(--sidebar-highlight-border);
  border-radius: 0 4px 4px 0;
  padding-left: 7.5px;
  box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--sidebar-highlight-border) 20%, transparent);
}

.sidebar-nav ul ul > li > a.active {
  padding-left: 17.5px;
}

.sidebar-nav ul ul ul > li > a.active {
  padding-left: 29.5px;
}

/* H2 前的装饰点 */
.sidebar-nav ul ul > li > a::before {
  content: '';
  position: absolute;
  left: 10px;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--sidebar-border-light);
  transition: background 0.14s;
}

.sidebar-nav ul ul > li > a:hover::before,
.sidebar-nav ul ul > li > a.active::before {
  background: var(--sidebar-accent);
}

.sidebar-nav ul ul > li > a.active::before {
  background: var(--sidebar-highlight-border);
}

/* ── 底部渐隐 ── */
.sidebar-fade-bottom {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 40px;
  background: linear-gradient(to top, var(--sidebar-bg-light), transparent);
  pointer-events: none;
  transition: opacity 0.18s;
}

/* ── 内容区 ── */
.doc-content {
  flex: 1;
  min-width: 0;
  padding: 4px 44px 56px;
}

.post-single {
  max-width: 100%;
  margin: 0;
}

/* ── 响应式 ── */
@media (max-width: 1100px) {
  .doc-sidebar { display: none; }
  .doc-content { padding: 0 20px 48px; }
  .doc-layout {
    width: 100%;
    margin: 0;
    max-width: 820px;
    margin: 0 auto;
  }
}

@media (max-width: 768px) {
  .doc-content { padding: 0 0 32px; }
}

.post-content {
  line-height: 1.8;
  font-family: var(--font-body-zh), var(--font-body-en);
  color: var(--text-primary);
}

.post-content h1,
.post-content h2,
.post-content h3,
.post-content h4,
.post-content h5,
.post-content h6 {
  font-family: var(--font-heading-zh), var(--font-heading-en);
  margin-top: var(--spacing-md);
  margin-bottom: var(--spacing-sm);
}

.post-content img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  box-shadow: var(--shadow);
  margin: var(--spacing-md) 0;
}

.post-content blockquote {
  border-left: 4px solid var(--primary-color);
  padding-left: var(--spacing-sm);
  margin: var(--spacing-md) 0;
  color: var(--text-secondary);
  font-style: italic;
  background: var(--card-bg);
  padding: var(--spacing-sm);
  border-radius: 4px;
}

/* 响应式设计 */
@media (max-width: 768px) {
  .hero-section {
    min-height: 300px;
    padding: var(--spacing-md) var(--spacing-sm);
  }
  
  .hero-buttons {
    flex-direction: column;
    width: 100%;
  }
  
  .hero-button {
    width: 100%;
    justify-content: center;
  }
  
  .post-card {
    margin-bottom: var(--spacing-sm);
  }
  
  .post-card-image {
    height: 150px;
  }
}

/* 动画效果 */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.post-card {
  animation: fadeInUp 0.5s ease-out;
}

/* 响应式设计优化 */
@media (max-width: 1024px) {
  .posts-grid {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  }
  
  .terms-grid {
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  }
}

@media (max-width: 768px) {
  :root {
    --h1-size: 2rem;
    --h2-size: 1.75rem;
    --h3-size: 1.25rem;
  }
  
  .hero-section {
    min-height: 300px;
    padding: var(--spacing-md) var(--spacing-sm);
    border-radius: 8px;
  }
  
  .hero-title {
    font-size: 1.75rem;
  }
  
  .hero-subtitle {
    font-size: 1rem;
  }
  
  .hero-buttons {
    flex-direction: column;
    width: 100%;
  }
  
  .hero-button {
    width: 100%;
    justify-content: center;
  }
  
  .posts-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-sm);
  }
  
  .post-card {
    margin-bottom: var(--spacing-sm);
  }
  
  .post-card-image {
    height: 150px;
  }
  
  .post-card-content {
    padding: var(--spacing-xs);
  }
  
  .terms-grid {
    grid-template-columns: 1fr;
  }
  
  .tags-cloud {
    padding: 1rem;
    min-height: 200px;
  }
  
  .tag-cloud-item {
    padding: 0.375rem 0.75rem;
    font-size: 0.875rem !important;
  }
  
  .content-section {
    margin-bottom: var(--spacing-md);
  }
  
  .section-title {
    font-size: 1.5rem;
  }
  
  .archive-month-group {
    margin-left: 0;
  }
  
  .archive-posts-list {
    margin-left: 0;
  }
  
  .archive-post-item {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .archive-post-date {
    margin-bottom: 0.25rem;
  }
  
  .archive-post-link {
    margin-left: 0;
  }
}

@media (max-width: 480px) {
  .hero-section {
    min-height: 250px;
    padding: var(--spacing-sm);
  }
  
  .hero-title {
    font-size: 1.5rem;
  }
  
  .hero-subtitle {
    font-size: 0.875rem;
  }
  
  .post-card-footer {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--spacing-xs);
  }
  
  .post-card-read-more {
    margin-top: var(--spacing-xs);
  }
}

/* 暗黑模式完善 */
[data-theme="dark"] .hero-section::before {
  opacity: 0.2;
}

[data-theme="dark"] .post-card {
  background: var(--card-bg);
  border-color: var(--border-color);
}

[data-theme="dark"] .term-card {
  background: var(--card-bg);
  border-color: var(--border-color);
}

[data-theme="dark"] .archive-stats > div > div {
  background: var(--card-bg);
}

[data-theme="dark"] .related-posts-list .related-post-card {
  background: var(--card-bg);
  border-color: var(--border-color);
}

[data-theme="dark"] .tags-cloud {
  background: var(--card-bg);
  border-color: var(--border-color);
}

[data-theme="dark"] .tag-cloud-item {
  background: rgba(66, 165, 245, 0.1);
  border-color: rgba(66, 165, 245, 0.2);
  color: var(--primary-color);
}

[data-theme="dark"] .tag-cloud-item:hover {
  background: var(--primary-color);
  color: #ffffff;
}

/* 打印样式 */
@media print {
  .hero-section,
  .nav,
  .hero-buttons,
  .post-card-footer,
  .term-card-footer,
  .archive-stats {
    display: none;
  }
  
  .post-card,
  .term-card {
    break-inside: avoid;
    box-shadow: none;
    border: 1px solid #ccc;
  }
}

/* =====================
   Tools Page
   ===================== */

.tools-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 12px;
  margin-top: 16px;
}

.tools-card {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 88px;
  padding: 12px;
  border-radius: 10px;
  background: #4a4a4a;
  color: #ffffff;
  text-decoration: none;
  transition: transform 0.15s ease, background 0.15s ease;
}

.tools-card:hover {
  transform: translateY(-2px);
  background: #3f3f3f;
}

.tools-card-title {
  font-weight: 600;
  text-align: center;
  word-break: break-word;
}

@media (max-width: 1024px) {
  .tools-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 640px) {
  .tools-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 420px) {
  .tools-grid {
    grid-template-columns: repeat(1, minmax(0, 1fr));
  }
}

/* 工具类 */
.text-center {
  text-align: center;
}

.mt-lg {
  margin-top: var(--spacing-lg);
}

.mb-lg {
  margin-bottom: var(--spacing-lg);
}

.mt-md {
  margin-top: var(--spacing-md);
}

.mb-md {
  margin-bottom: var(--spacing-md);
}

/* =====================
   Posts 目录页 - 左侧导航 + 右侧平铺
   ===================== */

:root {
  --pl-sidebar-w: 220px;
  --pl-sidebar-bg: #f7f5f0;
  --pl-sidebar-border: #e2ddd5;
  --pl-accent: #b5450c;
  --pl-accent-soft: rgba(181, 69, 12, 0.08);
  --pl-text: #1a1814;
  --pl-muted: #8a8278;
  --pl-card-bg: #ffffff;
  --pl-card-border: #ede9e3;
  --pl-tag-bg: #f0ece5;
  --pl-tag-text: #6b5d50;
}

[data-theme="dark"] {
  --pl-sidebar-bg: #141412;
  --pl-sidebar-border: #2a2826;
  --pl-accent: #e2784a;
  --pl-accent-soft: rgba(226, 120, 74, 0.1);
  --pl-text: #e8e4dc;
  --pl-muted: #7a7570;
  --pl-card-bg: #1c1a18;
  --pl-card-border: #2a2826;
  --pl-tag-bg: #242220;
  --pl-tag-text: #a09890;
}

.posts-layout {
  display: flex;
  align-items: flex-start;
  gap: 0;
  width: 100%;
  min-height: 80vh;
}

main:has(.posts-layout) {
  max-width: 100%;
  padding: 0;
}

main:has(.doc-layout) {
  max-width: 100%;
  padding: 0;
}

/* ── 左侧侧边栏 ── */
.posts-sidebar {
  position: sticky;
  top: 52px;
  width: var(--pl-sidebar-w);
  min-width: var(--pl-sidebar-w);
  max-height: calc(100vh - 60px);
  flex-shrink: 0;
  background: var(--pl-sidebar-bg);
  border-right: 1px solid var(--pl-sidebar-border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: width 0.22s cubic-bezier(.4,0,.2,1),
              min-width 0.22s cubic-bezier(.4,0,.2,1);
}

.posts-sidebar.is-collapsed {
  width: 38px;
  min-width: 38px;
}

.posts-sidebar.is-collapsed .posts-sidebar-label,
.posts-sidebar.is-collapsed .posts-nav {
  opacity: 0;
  pointer-events: none;
}

.posts-sidebar-inner {
  display: flex;
  flex-direction: column;
  height: 100%;
  overflow: hidden;
}

.posts-sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 14px 12px;
  border-bottom: 1px solid var(--pl-sidebar-border);
  flex-shrink: 0;
}

.posts-sidebar.is-collapsed .posts-sidebar-header {
  justify-content: center;
  padding: 16px 8px 12px;
}

.posts-sidebar-label {
  font-family: 'DM Sans', sans-serif;
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--pl-muted);
  transition: opacity 0.16s;
  white-space: nowrap;
}

.posts-sidebar-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  background: transparent;
  border: 1px solid var(--pl-sidebar-border);
  border-radius: 4px;
  color: var(--pl-muted);
  cursor: pointer;
  padding: 0;
  flex-shrink: 0;
  transition: border-color 0.14s, color 0.14s, background 0.14s;
}

.posts-sidebar-toggle:hover {
  border-color: var(--pl-accent);
  color: var(--pl-accent);
  background: var(--pl-accent-soft);
}

/* ── 导航树 ── */
.posts-nav {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 10px 8px 40px;
  scrollbar-width: thin;
  scrollbar-color: var(--pl-sidebar-border) transparent;
  scroll-behavior: smooth;
  transition: opacity 0.16s;
}

.posts-nav::-webkit-scrollbar { width: 2px; }
.posts-nav::-webkit-scrollbar-thumb {
  background: var(--pl-sidebar-border);
  border-radius: 2px;
}

.posts-nav-year { margin-bottom: 4px; }

.posts-nav-year-btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 5px 8px;
  background: transparent;
  border: none;
  cursor: pointer;
  font-family: 'DM Serif Display', serif;
  font-size: 0.9rem;
  color: var(--pl-text);
  border-radius: 5px;
  transition: background 0.12s;
}

.posts-nav-year-btn:hover {
  background: var(--pl-accent-soft);
}

.posts-nav-chevron {
  transition: transform 0.2s;
  flex-shrink: 0;
  opacity: 0.5;
}

.posts-nav-year-btn.is-open .posts-nav-chevron {
  transform: rotate(180deg);
}

.posts-nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.22s cubic-bezier(.4,0,.2,1);
}

.posts-nav-list.is-open {
  max-height: 1200px;
}

.posts-nav-item {
  display: flex;
  align-items: baseline;
  gap: 6px;
  padding: 4px 8px 4px 14px;
  text-decoration: none;
  border-radius: 4px;
  transition: background 0.12s, color 0.12s;
  cursor: pointer;
}

.posts-nav-item:hover {
  background: var(--pl-accent-soft);
  text-decoration: none;
}

.posts-nav-item.is-active {
  background: var(--pl-accent-soft);
  border-left: 2px solid var(--pl-accent);
  border-radius: 0 4px 4px 0;
  padding-left: 12px;
}

.posts-nav-date {
  font-family: 'DM Sans', monospace;
  font-size: 0.68rem;
  color: var(--pl-muted);
  white-space: nowrap;
  flex-shrink: 0;
}

.posts-nav-title {
  font-family: 'DM Sans', 'PingFang SC', sans-serif;
  font-size: 0.78rem;
  color: var(--pl-text);
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.posts-nav-item.is-active .posts-nav-title {
  color: var(--pl-accent);
}

/* ── 右侧文章列表 ── */
.posts-feed {
  flex: 1;
  min-width: 0;
  padding: 12px 48px 64px 40px;
}

/* ── 文章卡片 ── */
.pf-card {
  display: flex;
  align-items: flex-start;
  padding: 28px 0;
  border-bottom: 1px solid var(--pl-card-border);
  opacity: 0;
  transform: translateY(12px);
  animation: pfFadeUp 0.4s ease forwards;
}

.pf-card:first-child {
  padding-top: 12px;
}

@keyframes pfFadeUp {
  to { opacity: 1; transform: translateY(0); }
}

.pf-card:nth-child(1) { animation-delay: 0.04s; }
.pf-card:nth-child(2) { animation-delay: 0.08s; }
.pf-card:nth-child(3) { animation-delay: 0.12s; }
.pf-card:nth-child(4) { animation-delay: 0.16s; }
.pf-card:nth-child(5) { animation-delay: 0.20s; }
.pf-card:nth-child(6) { animation-delay: 0.24s; }
.pf-card:nth-child(n+7) { animation-delay: 0.28s; }

.pf-card-main {
  flex: 1;
  min-width: 0;
}

.pf-card-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
}

.pf-date {
  font-family: 'DM Sans', monospace;
  font-size: 0.75rem;
  font-weight: 300;
  letter-spacing: 0.05em;
  color: var(--pl-muted);
}

.pf-dot {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--pl-sidebar-border);
  flex-shrink: 0;
}

.pf-reading {
  font-family: 'DM Sans', sans-serif;
  font-size: 0.72rem;
  color: var(--pl-muted);
}

.pf-title {
  font-family: 'DM Serif Display', 'Noto Serif SC', serif;
  font-size: 1.45rem;
  font-weight: 400;
  line-height: 1.35;
  margin: 0 0 10px 0;
  color: var(--pl-text);
}

.pf-title a {
  color: inherit;
  text-decoration: none;
  transition: color 0.15s;
}

.pf-title a:hover {
  color: var(--pl-accent);
  text-decoration: none;
}

.pf-summary {
  font-family: 'DM Sans', 'PingFang SC', sans-serif;
  font-size: 0.9rem;
  line-height: 1.7;
  color: var(--pl-muted);
  margin: 0 0 14px 0;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.pf-footer {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
}

.pf-tag {
  display: inline-block;
  padding: 3px 10px;
  font-family: 'DM Sans', sans-serif;
  font-size: 0.7rem;
  background: var(--pl-tag-bg);
  color: var(--pl-tag-text);
  border-radius: 3px;
  text-decoration: none;
  transition: background 0.14s, color 0.14s;
}

.pf-tag:hover {
  background: var(--pl-accent);
  color: #fff;
  text-decoration: none;
}

.pf-read {
  margin-left: auto;
  font-family: 'DM Sans', sans-serif;
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--pl-accent);
  text-decoration: none;
  letter-spacing: 0.02em;
  transition: opacity 0.14s, letter-spacing 0.18s;
  white-space: nowrap;
}

.pf-read:hover {
  opacity: 0.75;
  letter-spacing: 0.06em;
  text-decoration: none;
}

/* ── 分页 ── */
.pf-pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 24px;
  padding: 40px 0 0;
}

.pf-page-btn {
  font-family: 'DM Sans', sans-serif;
  font-size: 0.85rem;
  color: var(--pl-accent);
  text-decoration: none;
  padding: 7px 18px;
  border: 1px solid var(--pl-accent);
  border-radius: 4px;
  transition: background 0.14s, color 0.14s;
}

.pf-page-btn:hover {
  background: var(--pl-accent);
  color: #fff;
  text-decoration: none;
}

.pf-page-info {
  font-family: 'DM Sans', sans-serif;
  font-size: 0.8rem;
  color: var(--pl-muted);
}

.posts-empty {
  text-align: center;
  color: var(--pl-muted);
  padding: 4rem 0;
  font-family: 'DM Sans', sans-serif;
}

/* ── 响应式 ── */
@media (max-width: 960px) {
  .posts-sidebar {
    display: none;
  }
  .posts-feed {
    padding: 12px 20px 48px;
  }
  .posts-layout {
    width: 100%;
    margin: 0;
  }
}

@media (max-width: 640px) {
  .posts-feed {
    padding: 8px 4px 32px;
  }
  .pf-title {
    font-size: 1.2rem;
  }
}