/* ==========================================================================
   爱国自研国产操作系统 · 用户指南 (Aiguo-OS User Guide)
   Design: Minimalist Socialist Constructivist Aesthetic (简约共产主义现代美学)
   ========================================================================== */

:root {
  --primary: #9E1B1B;
  --primary-light: #B82424;
  --primary-hover: #801414;
  --primary-glow: rgba(158, 27, 27, 0.12);
  --accent: #E5B63E;
  --accent-hover: #D4A017;
  
  --bg-page: #F6F5F2;
  --bg-surface: #FFFFFF;
  --bg-subtle: #ECEAE4;
  --bg-hover: #F0EEE8;
  --border-color: #E2DFD7;
  --border-subtle: #ECE9E1;
  
  --text-main: #1D1E20;
  --text-muted: #5E626B;
  --text-light: #8E929C;
  --text-inverse: #FFFFFF;

  --code-bg: #1B1D21;
  --code-text: #E6EDF3;
  --quote-bg: rgba(158, 27, 27, 0.04);
  --badge-bg: rgba(158, 27, 27, 0.08);

  --sidebar-w: 290px;
  --toc-w: 240px;
  --header-h: 60px;
  
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "WenQuanYi Micro Hei", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

[data-theme="dark"] {
  --primary: #C52828;
  --primary-light: #DE3636;
  --primary-hover: #A81B1B;
  --primary-glow: rgba(197, 40, 40, 0.2);
  --accent: #F1C40F;
  --accent-hover: #F39C12;
  
  --bg-page: #141518;
  --bg-surface: #1E2024;
  --bg-subtle: #272A30;
  --bg-hover: #2D3138;
  --border-color: #33373F;
  --border-subtle: #272A30;
  
  --text-main: #ECEEF2;
  --text-muted: #9BA1AC;
  --text-light: #6E7582;
  --text-inverse: #141518;

  --code-bg: #0E1012;
  --code-text: #E6EDF3;
  --quote-bg: rgba(197, 40, 40, 0.08);
  --badge-bg: rgba(197, 40, 40, 0.16);
  --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);
}

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

html {
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-page);
  color: var(--text-main);
  line-height: 1.75;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Top Navbar */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-h);
  background: var(--bg-surface);
  border-bottom: 2px solid var(--primary);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.header-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: inherit;
}

.brand-star {
  color: var(--primary);
  font-size: 1.4rem;
  line-height: 1;
  filter: drop-shadow(0 0 4px var(--primary-glow));
}

.brand-info {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  color: var(--text-main);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.brand-badge {
  font-size: 0.68rem;
  background: var(--badge-bg);
  color: var(--primary);
  padding: 0.1rem 0.4rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  border: 1px solid rgba(158, 27, 27, 0.2);
}

.brand-sub {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Header Actions */
.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.search-trigger {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--bg-page);
  border: 1px solid var(--border-color);
  padding: 0.45rem 0.9rem;
  border-radius: 20px;
  font-size: 0.85rem;
  color: var(--text-muted);
  cursor: pointer;
  transition: var(--transition);
  min-width: 200px;
}

.search-trigger:hover {
  border-color: var(--primary);
  color: var(--text-main);
  background: var(--bg-surface);
}

.search-key {
  margin-left: auto;
  font-size: 0.72rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 0.1rem 0.35rem;
  font-family: var(--font-mono);
}

.theme-toggle-btn, .mobile-toggle-btn {
  background: var(--bg-page);
  border: 1px solid var(--border-color);
  width: 38px;
  height: 38px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-muted);
  transition: var(--transition);
}

.theme-toggle-btn:hover, .mobile-toggle-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--bg-surface);
}

.mobile-toggle-btn {
  display: none;
}

/* Main Layout */
.layout-container {
  display: flex;
  margin-top: var(--header-h);
  min-height: calc(100vh - var(--header-h));
}

/* Left Sidebar Navigation */
.sidebar-left {
  width: var(--sidebar-w);
  flex-shrink: 0;
  background: var(--bg-surface);
  border-right: 1px solid var(--border-color);
  position: sticky;
  top: var(--header-h);
  height: calc(100vh - var(--header-h));
  overflow-y: auto;
  padding: 1.25rem 0.75rem 2rem;
  scrollbar-width: thin;
}

.sidebar-category {
  margin-bottom: 1.5rem;
}

.category-title {
  font-size: 0.76rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-light);
  padding: 0.25rem 0.75rem 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.nav-doc-list {
  list-style: none;
}

.nav-doc-item {
  margin-bottom: 2px;
}

.nav-doc-link {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  padding: 0.55rem 0.75rem;
  border-radius: var(--radius-md);
  text-decoration: none;
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  transition: var(--transition);
  position: relative;
}

.nav-doc-link:hover {
  background: var(--bg-hover);
  color: var(--text-main);
}

.nav-doc-link.active {
  background: var(--primary-glow);
  color: var(--primary);
  font-weight: 600;
}

.nav-doc-link.active::before {
  content: '';
  position: absolute;
  left: 0;
  top: 6px;
  bottom: 6px;
  width: 3.5px;
  background: var(--primary);
  border-radius: 0 4px 4px 0;
}

.nav-doc-icon {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  opacity: 0.75;
}

.nav-doc-link.active .nav-doc-icon {
  opacity: 1;
  color: var(--primary);
}

/* Center Content Area */
.main-content-wrap {
  flex: 1;
  min-width: 0;
  padding: 2.5rem 3rem 5rem;
  display: flex;
  justify-content: center;
}

.content-article {
  max-width: 860px;
  width: 100%;
}

/* Article Header */
.article-header {
  border-bottom: 2px solid var(--border-color);
  padding-bottom: 1.25rem;
  margin-bottom: 2.25rem;
}

.article-category-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--primary);
  background: var(--badge-bg);
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  margin-bottom: 0.75rem;
  border-left: 3px solid var(--primary);
}

.article-title {
  font-size: 2.1rem;
  font-weight: 800;
  line-height: 1.3;
  color: var(--text-main);
  letter-spacing: -0.3px;
}

/* Markdown Content Elements */
.markdown-body {
  font-size: 1.02rem;
  color: var(--text-main);
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4 {
  color: var(--text-main);
  line-height: 1.35;
  scroll-margin-top: calc(var(--header-h) + 1.5rem);
  position: relative;
}

.markdown-body h1 {
  font-size: 1.75rem;
  font-weight: 800;
  margin-top: 2.75rem;
  margin-bottom: 1.2rem;
  border-bottom: 2px solid var(--border-color);
  padding-bottom: 0.6rem;
}

.markdown-body h2 {
  font-size: 1.32rem;
  font-weight: 700;
  margin-top: 2rem;
  margin-bottom: 0.9rem;
  padding-left: 0.65rem;
  border-left: 3.5px solid var(--primary);
}

.markdown-body h3 {
  font-size: 1.12rem;
  font-weight: 600;
  margin-top: 1.6rem;
  margin-bottom: 0.75rem;
  padding-left: 0.55rem;
  border-left: 2.5px solid var(--border-color);
  color: var(--text-main);
}

.markdown-body h4 {
  font-size: 1.02rem;
  font-weight: 600;
  margin-top: 1.25rem;
  margin-bottom: 0.5rem;
  color: var(--text-muted);
}

.markdown-body p {
  margin-bottom: 1.2rem;
  word-break: break-word;
}

.markdown-body strong {
  font-weight: 700;
  color: var(--text-main);
}

.markdown-body s,
.markdown-body del {
  color: var(--text-muted);
  text-decoration: line-through;
  text-decoration-thickness: 1.5px;
}

.markdown-body a {
  color: var(--primary);
  text-decoration: none;
  border-bottom: 1px dashed var(--primary);
  transition: var(--transition);
  padding-bottom: 1px;
}

.markdown-body a:hover {
  border-bottom-style: solid;
  color: var(--primary-light);
}

.markdown-body blockquote {
  margin: 1.5rem 0;
  padding: 0.9rem 1.25rem;
  background: var(--quote-bg);
  border-left: 4px solid var(--primary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  color: var(--text-muted);
}

.markdown-body blockquote p:last-child {
  margin-bottom: 0;
}

.markdown-body ul,
.markdown-body ol {
  margin: 1rem 0 1.5rem 1.75rem;
}

.markdown-body li {
  margin-bottom: 0.5rem;
}

.markdown-body code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--bg-subtle);
  color: var(--primary);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

.markdown-body pre {
  margin: 1.5rem 0;
  background: var(--code-bg);
  color: var(--code-text);
  padding: 1.25rem;
  border-radius: var(--radius-md);
  overflow-x: auto;
  position: relative;
  box-shadow: var(--shadow-sm);
}

.markdown-body pre code {
  background: transparent;
  color: inherit;
  border: none;
  padding: 0;
  font-size: 0.9em;
}

/* Tables */
.markdown-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.95rem;
}

.markdown-body th,
.markdown-body td {
  border: 1px solid var(--border-color);
  padding: 0.6rem 1rem;
  text-align: left;
}

.markdown-body th {
  background: var(--bg-subtle);
  font-weight: 700;
}

.markdown-body tr:nth-child(even) {
  background: var(--bg-hover);
}

/* Image Container */
.markdown-body img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 1.75rem auto;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-color);
  cursor: zoom-in;
  transition: var(--transition);
}

.markdown-body img:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

/* Table */
.markdown-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.75rem 0;
  background: var(--bg-surface);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
}

.markdown-body th,
.markdown-body td {
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-color);
  text-align: left;
}

.markdown-body th {
  background: var(--bg-subtle);
  font-weight: 700;
  color: var(--text-main);
  border-bottom: 2px solid var(--primary);
}

.markdown-body tr:nth-child(even) {
  background: var(--bg-hover);
}

/* Bottom Page Navigation */
.doc-footer-nav {
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  gap: 1rem;
}

.footer-nav-card {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 1rem 1.25rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  text-decoration: none;
  color: inherit;
  transition: var(--transition);
}

.footer-nav-card:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.footer-nav-card.next {
  text-align: right;
  align-items: flex-end;
}

.footer-nav-sub {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--text-light);
  letter-spacing: 0.5px;
  margin-bottom: 0.25rem;
}

.footer-nav-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--primary);
}

/* Right TOC Sidebar */
.sidebar-right {
  width: var(--toc-w);
  flex-shrink: 0;
  position: sticky;
  top: var(--header-h);
  height: calc(100vh - var(--header-h));
  overflow-y: auto;
  padding: 2.5rem 1.25rem 2rem 0.5rem;
}

.toc-header {
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  color: var(--text-light);
  margin-bottom: 0.85rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.toc-list {
  list-style: none;
  border-left: 1.5px solid var(--border-color);
  padding-left: 0.4rem;
}

.toc-item {
  margin-bottom: 0.2rem;
}

.toc-link {
  display: block;
  text-decoration: none;
  line-height: 1.45;
  transition: var(--transition);
  border-radius: 4px;
  position: relative;
  word-break: break-word;
}

/* Level 1: Primary Section */
.toc-item.level-1 {
  margin-top: 0.75rem;
  margin-bottom: 0.3rem;
}

.toc-item.level-1:first-child {
  margin-top: 0;
}

.toc-item.level-1 .toc-link {
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--text-main);
  padding: 0.22rem 0.5rem;
}

/* Level 2: Subsections (indented with bullet dot indicator) */
.toc-item.level-2 {
  margin-bottom: 0.2rem;
}

.toc-item.level-2 .toc-link {
  font-size: 0.79rem;
  font-weight: 400;
  color: var(--text-muted);
  padding: 0.18rem 0.5rem 0.18rem 1.35rem;
}

.toc-item.level-2 .toc-link::before {
  content: "";
  position: absolute;
  left: 0.55rem;
  top: 50%;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background-color: var(--border-color);
  transform: translateY(-50%);
  transition: var(--transition);
}

.toc-item.level-2 .toc-link:hover::before,
.toc-item.level-2 .toc-link.active::before {
  background-color: var(--primary);
}

/* Level 3: Sub-subsections (further indented) */
.toc-item.level-3 {
  margin-bottom: 0.18rem;
}

.toc-item.level-3 .toc-link {
  font-size: 0.74rem;
  font-weight: 400;
  color: var(--text-light);
  padding: 0.15rem 0.5rem 0.15rem 2.05rem;
}

.toc-item.level-3 .toc-link::before {
  content: "";
  position: absolute;
  left: 1.4rem;
  top: 50%;
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background-color: var(--border-color);
  transform: translateY(-50%);
  transition: var(--transition);
}

.toc-item.level-3 .toc-link:hover::before,
.toc-item.level-3 .toc-link.active::before {
  background-color: var(--primary);
}

/* Level 4: Deep subsections */
.toc-item.level-4 .toc-link {
  padding-left: 2.65rem;
  font-size: 0.71rem;
  font-weight: 400;
  color: var(--text-light);
}

.toc-link:hover {
  color: var(--primary);
  background: var(--bg-hover);
}

.toc-link.active {
  color: var(--primary);
  font-weight: 600;
  background: var(--primary-glow);
}

.toc-item.level-1 .toc-link.active {
  font-weight: 700;
}

.toc-empty {
  font-size: 0.82rem;
  color: var(--text-light);
  font-style: italic;
}

/* Lightbox Modal */
.lightbox-modal {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.88);
  backdrop-filter: blur(6px);
  z-index: 1000;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  cursor: zoom-out;
  opacity: 0;
  transition: opacity 0.25s ease;
}

.lightbox-modal.active {
  display: flex;
  opacity: 1;
}

.lightbox-img {
  max-width: 95vw;
  max-height: 92vh;
  border-radius: var(--radius-md);
  box-shadow: 0 10px 40px rgba(0,0,0,0.5);
  border: 1px solid rgba(255,255,255,0.15);
  cursor: default;
}

.lightbox-close {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  background: rgba(255, 255, 255, 0.15);
  border: none;
  color: white;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  font-size: 1.5rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.lightbox-close:hover {
  background: var(--primary);
}

/* Search Modal */
.search-modal {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  z-index: 900;
  display: none;
  justify-content: center;
  padding-top: 12vh;
  opacity: 0;
  transition: opacity 0.2s ease;
}

.search-modal.active {
  display: flex;
  opacity: 1;
}

.search-box {
  background: var(--bg-surface);
  width: 100%;
  max-width: 600px;
  max-height: 70vh;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  border: 2px solid var(--primary);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.search-input-wrap {
  display: flex;
  align-items: center;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
  gap: 0.75rem;
}

.search-input {
  flex: 1;
  border: none;
  background: transparent;
  font-size: 1.05rem;
  color: var(--text-main);
  outline: none;
}

.search-results {
  flex: 1;
  overflow-y: auto;
  padding: 0.5rem;
}

.search-result-item {
  padding: 0.75rem 1rem;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition);
  margin-bottom: 0.25rem;
}

.search-result-item:hover,
.search-result-item.selected {
  background: var(--primary-glow);
}

.search-result-title {
  font-weight: 600;
  color: var(--primary);
  font-size: 0.95rem;
  margin-bottom: 0.2rem;
}

.search-result-snippet {
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.4;
}

.search-result-snippet mark {
  background: var(--accent);
  color: #000;
  padding: 0.1rem 0.2rem;
  border-radius: 2px;
}

.search-empty {
  padding: 2.5rem;
  text-align: center;
  color: var(--text-light);
  font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 1200px) {
  .sidebar-right {
    display: none;
  }
  .main-content-wrap {
    padding: 2rem 2rem 4rem;
  }
}

@media (max-width: 768px) {
  .mobile-toggle-btn {
    display: flex;
  }
  .search-trigger {
    min-width: unset;
    padding: 0.45rem;
  }
  .search-trigger span {
    display: none;
  }
  .sidebar-left {
    position: fixed;
    left: -100%;
    top: var(--header-h);
    bottom: 0;
    z-index: 80;
    transition: left 0.3s ease;
    box-shadow: var(--shadow-lg);
  }
  .sidebar-left.open {
    left: 0;
  }
  .main-content-wrap {
    padding: 1.5rem 1rem 3rem;
  }
  .article-title {
    font-size: 1.6rem;
  }
}


/* ==========================================================================
   Backlinks (双向链接 / 反向引用) Styles
   ========================================================================== */
.backlinks-container {
  margin-top: 3.5rem;
  padding: 1.5rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--primary);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
}

.backlinks-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 1rem;
}

.backlinks-icon {
  color: var(--primary);
  font-size: 1.1rem;
}

.backlinks-badge {
  font-size: 0.72rem;
  background: var(--badge-bg);
  color: var(--primary);
  padding: 0.1rem 0.45rem;
  border-radius: 10px;
  font-weight: 600;
}

.backlinks-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.75rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.backlinks-item {
  margin: 0;
}

.backlinks-card {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.65rem 0.9rem;
  background: var(--bg-page);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: var(--text-main);
  font-size: 0.88rem;
  font-weight: 500;
  transition: var(--transition);
}

.backlinks-card:hover {
  background: var(--bg-surface);
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.backlinks-card-icon {
  color: var(--primary);
  opacity: 0.8;
  flex-shrink: 0;
}

.internal-doc-link {
  color: var(--primary) !important;
  font-weight: 600;
  text-decoration: none !important;
  border-bottom: 1.5px solid var(--primary) !important;
  padding: 0 2px;
  border-radius: 2px;
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 2px;
}

.internal-doc-link::before {
  content: '📄 ';
  font-size: 0.82em;
  opacity: 0.8;
}

.internal-doc-link:hover {
  background: var(--primary-glow);
  border-bottom-color: var(--primary-hover) !important;
  color: var(--primary-hover) !important;
}