@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap');

/* ==========================================================================
   Variables & Themes
   ========================================================================== */

:root,
[data-theme='light'] {
  --color-bg-primary: #FAF9F5;
  --color-bg-secondary: #F4F3EE;
  --color-bg-card: #FFFFFF;
  --color-text-primary: #141413;
  --color-text-secondary: #6B6966;
  --color-border: #E8E6DC;
  --color-accent: #D97757;
  --color-accent-hover: #C15F3C;
  --color-accent-light: rgba(217, 119, 87, 0.1);
  --color-accent-rgb: 217, 119, 87;

  /* Code block specific */
  --color-code-bg: var(--color-bg-secondary);
}

[data-theme='dark'] {
  --color-bg-primary: #141413;
  --color-bg-secondary: #1A1A18;
  --color-bg-card: #1E1E1C;
  --color-text-primary: #F5F4EF;
  --color-text-secondary: #A3A09A;
  --color-border: #2E2E2B;
  --color-accent: #E08A6D;
  --color-accent-hover: #D97757;
  --color-accent-light: rgba(224, 138, 109, 0.1);
  --color-accent-rgb: 224, 138, 109;

  /* Code block specific */
  --color-code-bg: #0D1117;
}

:root {
  /* Fonts */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  /* Shadows (warm-toned) */
  --shadow-sm: 0 2px 8px rgba(40, 30, 20, 0.05);
  --shadow-md: 0 4px 16px rgba(40, 30, 20, 0.08);
  --shadow-lg: 0 8px 32px rgba(40, 30, 20, 0.12);

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.3s ease;

  /* Layout */
  --navbar-height: 64px;
  --sidebar-width: 260px;
}

/* ==========================================================================
   1. Global Reset & Base
   ========================================================================== */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  overflow-x: hidden;
  max-width: 100%;
}

body {
  margin: 0;
  padding: 0;
  padding-bottom: env(safe-area-inset-bottom, 0px);
  background-color: var(--color-bg-primary);
  color: var(--color-text-primary);
  font-family: var(--font-sans);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  max-width: 100%;
}

::selection {
  background-color: var(--color-accent);
  color: #fff;
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--color-bg-primary);
}

::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: var(--radius-lg);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-text-secondary);
}

/* ==========================================================================
   2. Typography Scale
   ========================================================================== */

h1, h2, h3, h4, h5, h6 {
  margin-top: 0;
  margin-bottom: 0.5em;
  color: var(--color-text-primary);
  font-weight: 700;
  line-height: 1.2;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

body {
  font-size: 1rem; /* 16px */
}

@media (max-width: 767px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.75rem; }
  h3 { font-size: 1.35rem; }
  h4 { font-size: 1.15rem; }
}

/* ==========================================================================
   3 & 4. Navigation Bar
   ========================================================================== */

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--navbar-height);
  background-color: rgba(250, 249, 245, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
}

[data-theme='dark'] .navbar {
  background-color: rgba(20, 20, 19, 0.85);
}

.navbar .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
}

.nav-brand {
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--color-accent);
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
  margin: 0;
  padding: 0;
  align-items: center;
}

.nav-link {
  text-decoration: none;
  color: var(--color-text-secondary);
  font-weight: 500;
  position: relative;
  transition: color var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-accent);
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--color-accent);
  border-radius: var(--radius-sm);
}

.theme-toggle {
  border: none;
  background: transparent;
  cursor: pointer;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background-color var(--transition-fast);
}

.theme-toggle:hover {
  background-color: var(--color-bg-secondary);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
  color: var(--color-text-primary);
}

/* Icon visibility per theme */
[data-theme='light'] .icon-sun {
  display: none;
}
[data-theme='light'] .icon-moon {
  display: block;
}
[data-theme='dark'] .icon-sun {
  display: block;
}
[data-theme='dark'] .icon-moon {
  display: none;
}

.mobile-menu-btn {
  display: none;
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 8px;
  color: var(--color-text-primary);
  border-radius: var(--radius-sm);
  transition: background-color var(--transition-fast);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

@media (max-width: 767px) {
  .mobile-menu-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 42px;
    height: 42px;
  }

  .mobile-menu-btn:hover,
  .mobile-menu-btn:active {
    background-color: var(--color-bg-secondary);
  }

  .nav-links {
    display: flex;
    position: absolute;
    top: var(--navbar-height);
    left: 0;
    width: 100%;
    flex-direction: column;
    background-color: var(--color-bg-card);
    border-bottom: 1px solid var(--color-border);
    padding: 12px 16px;
    gap: 4px;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s ease;
    pointer-events: none;
  }

  .nav-links.open {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    pointer-events: auto;
  }

  .nav-link {
    padding: 12px 16px;
    width: 100%;
    display: block;
    border-radius: var(--radius-md);
    font-size: 1rem;
  }

  .nav-link:hover,
  .nav-link.active {
    background-color: var(--color-accent-light);
  }

  .nav-actions {
    padding: 10px 16px 6px;
    border-top: 1px solid var(--color-border);
    margin-top: 6px;
    justify-content: flex-start;
    gap: 16px;
  }
}

/* ==========================================================================
   5. Hero Section
   ========================================================================== */

.hero {
  padding-top: calc(var(--navbar-height) + 60px);
  padding-bottom: 60px;
  text-align: center;
}

.hero-title {
  font-size: 3rem;
  font-weight: 800;
  margin-bottom: 16px;
}

.hero-title .accent {
  color: var(--color-accent);
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--color-text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

@media (max-width: 767px) {
  .hero-title {
    font-size: 2rem;
  }
  .hero-subtitle {
    font-size: 1rem;
  }
}

/* ==========================================================================
   6. Container
   ========================================================================== */

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ==========================================================================
   7. Posts Grid
   ========================================================================== */

.posts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 24px;
  padding-bottom: 60px;
}

@media (max-width: 767px) {
  .posts-grid {
    grid-template-columns: 1fr;
  }
}

/* ==========================================================================
   8. Post Card
   ========================================================================== */

.post-card {
  background-color: var(--color-bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  padding: 28px;
  transition: transform var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
  cursor: pointer;
  text-decoration: none;
  display: block;
}

.post-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-accent); /* subtle */
}

.post-card-category {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-accent);
  background-color: var(--color-accent-light);
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 12px;
}

.post-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--color-text-primary);
  line-height: 1.4;
}

.post-card-summary {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin-bottom: 16px;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.post-card-meta {
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  display: flex;
  gap: 16px;
  align-items: center;
}

.post-card-tags {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-top: 12px;
}

.tag {
  font-size: 0.75rem;
  color: var(--color-text-secondary);
  padding: 2px 8px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
}

/* ==========================================================================
   9. Archive File Explorer
   ========================================================================== */

.archive-layout {
  display: flex;
  min-height: calc(100vh - var(--navbar-height));
  padding-top: var(--navbar-height);
}

.archive-sidebar {
  width: var(--sidebar-width);
  background-color: var(--color-bg-secondary);
  border-right: 1px solid var(--color-border);
  padding: 20px 0;
  overflow-y: auto;
  flex-shrink: 0;
  position: sticky;
  top: var(--navbar-height);
  height: calc(100vh - var(--navbar-height));
}

.sidebar-header {
  padding: 0 20px 16px;
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.folder-tree {
  list-style: none;
  padding: 0;
  margin: 0;
}

.tree-item {
  user-select: none;
}

.tree-folder {
  display: flex;
  align-items: center;
  padding: 8px 20px;
  cursor: pointer;
  transition: background-color var(--transition-fast);
  gap: 8px;
  font-size: 0.9rem;
  color: var(--color-text-primary);
}

.tree-folder:hover {
  background-color: rgba(var(--color-accent-rgb), 0.05);
}

.tree-folder.active {
  background-color: var(--color-accent-light);
  color: var(--color-accent);
  font-weight: 600;
}

.tree-folder .folder-icon {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  color: var(--color-accent);
}

.tree-folder .toggle-icon {
  width: 14px;
  height: 14px;
  transition: transform 0.2s;
  color: var(--color-text-secondary);
  margin-right: 4px;
}

.tree-folder.expanded .toggle-icon {
  transform: rotate(90deg);
}

.tree-children {
  list-style: none;
  padding-left: 20px;
  margin: 0;
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.3s ease;
}

.tree-children.open {
  max-height: 1000px;
}

.archive-content {
  flex: 1;
  padding: 24px;
  min-width: 0;
}

.archive-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--color-border);
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  flex-wrap: wrap;
}

.breadcrumb-item {
  color: var(--color-text-secondary);
  cursor: pointer;
}

.breadcrumb-item:hover {
  color: var(--color-accent);
}

.breadcrumb-item.current {
  color: var(--color-text-primary);
  font-weight: 600;
  cursor: default;
}

.breadcrumb-separator {
  color: var(--color-text-secondary);
  font-size: 0.8rem;
}

.view-toggle {
  display: flex;
  gap: 4px;
}

.view-btn {
  width: 36px;
  height: 36px;
  border: none;
  background: transparent;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-secondary);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.view-btn:hover {
  background-color: var(--color-bg-secondary);
}

.view-btn.active {
  background-color: var(--color-accent-light);
  color: var(--color-accent);
}

.file-list-header {
  display: grid;
  grid-template-columns: 1fr 140px 100px;
  padding: 10px 16px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  border-bottom: 1px solid var(--color-border);
}

.file-item {
  display: grid;
  grid-template-columns: 1fr 140px 100px;
  padding: 12px 16px;
  border-bottom: 1px solid rgba(0,0,0,0.03); /* very subtle */
  transition: background-color var(--transition-fast);
  cursor: pointer;
  align-items: center;
}

[data-theme='dark'] .file-item {
  border-bottom: 1px solid rgba(255,255,255,0.03);
}

.file-item:hover {
  background-color: var(--color-accent-light);
}

.file-item-name {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--color-text-primary);
}

.file-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

.file-icon.folder {
  color: #F59E0B;
}

.file-icon.file {
  color: var(--color-text-secondary);
}

.file-item-date {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
}

.file-item-size {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  text-align: right;
}

.file-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 16px;
}

.file-grid-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 20px 12px;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color var(--transition-fast);
  text-align: center;
  gap: 10px;
}

.file-grid-item:hover {
  background-color: var(--color-accent-light);
}

.grid-icon {
  width: 48px;
  height: 48px;
}

.grid-icon.folder {
  color: #F59E0B;
}

.grid-icon.file {
  color: var(--color-text-secondary);
}

.grid-name {
  font-size: 0.85rem;
  color: var(--color-text-primary);
  word-break: break-word;
}

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

@media (max-width: 767px) {
  .archive-layout {
    flex-direction: column;
  }
  
    padding-left: 16px;
    padding-right: 16px;
  }
  
  .sidebar-toggle-btn {
    display: flex;
    align-items: center;
    margin: 16px 0 8px;
    padding: 10px 16px;
    background-color: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text-primary);
    gap: 8px;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.9rem;
    box-shadow: var(--shadow-sm);
    width: fit-content;
  }

  .archive-sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: 280px;
    height: 100vh;
    z-index: 1500;
    background-color: var(--color-bg-card);
    border-right: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
    transform: translateX(-100%);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: block;
    padding-top: calc(var(--navbar-height) + 16px);
  }
  
  .archive-sidebar.open {
    transform: translateX(0);
  }

  .sidebar-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.4);
    backdrop-filter: blur(2px);
    -webkit-backdrop-filter: blur(2px);
    z-index: 1400;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
  }

  .sidebar-backdrop.active {
    opacity: 1;
    pointer-events: auto;
  }

  .breadcrumb {
    overflow-x: auto;
    white-space: nowrap;
    -webkit-overflow-scrolling: touch;
    padding-bottom: 4px;
    max-width: 100%;
    flex-wrap: nowrap;
  }
  
  .archive-toolbar {
    flex-wrap: wrap;
    gap: 12px;
  }

  .file-list-header {
    grid-template-columns: 1fr;
  }
  .file-list-header > div:not(:first-child),
  .file-list-header > span:not(:first-child) {
    display: none;
  }
  
  .file-item {
    grid-template-columns: 1fr;
    padding: 12px 14px;
  }
  .file-item-date,
  .file-item-size {
    display: none;
  }

  .file-grid {
    grid-template-columns: repeat(auto-fill, minmax(105px, 1fr));
    gap: 12px;
  }

  .file-grid-item {
    padding: 16px 8px;
  }
}

/* ==========================================================================
   10. About Page
   ========================================================================== */

.about-page {
  padding-top: calc(var(--navbar-height) + 40px);
  padding-bottom: 60px;
}

.profile-card {
  text-align: center;
  padding: 40px 20px;
  margin-bottom: 48px;
}

.avatar {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  margin: 0 auto 24px;
  display: block;
  object-fit: cover;
  background-color: var(--color-bg-secondary);
}

.profile-name {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.profile-bio {
  font-size: 1.1rem;
  color: var(--color-text-secondary);
  max-width: 500px;
  margin: 0 auto;
  line-height: 1.7;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 24px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-accent);
}

.skills-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 48px;
}

.skill-tag {
  padding: 8px 16px;
  border: 1px solid var(--color-border);
  border-radius: 20px;
  font-size: 0.85rem;
  color: var(--color-text-primary);
  transition: border-color var(--transition-fast), color var(--transition-fast), background-color var(--transition-fast);
}

.skill-tag:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background-color: var(--color-accent-light);
}

.timeline {
  position: relative;
  padding-left: 32px;
  margin-bottom: 48px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 11px;
  top: 0;
  bottom: 0;
  width: 2px;
  background-color: var(--color-border);
}

.timeline-item {
  position: relative;
  margin-bottom: 32px;
}

.timeline-dot {
  position: absolute;
  left: -32px;
  top: 4px;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background-color: var(--color-accent);
  border: 4px solid var(--color-bg-primary);
}

.timeline-content {
  background-color: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 20px;
}

.timeline-date {
  font-size: 0.8rem;
  color: var(--color-accent);
  font-weight: 600;
  margin-bottom: 8px;
}

.timeline-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.timeline-desc {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

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

.social-link {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-secondary);
  transition: border-color var(--transition-fast), color var(--transition-fast), background-color var(--transition-fast);
}

.social-link:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background-color: var(--color-accent-light);
}

.social-link svg {
  width: 22px;
  height: 22px;
}

/* ==========================================================================
   11. Post Detail Page
   ========================================================================== */

.post-page {
  padding-top: calc(var(--navbar-height) + 40px);
  max-width: 760px;
  margin: 0 auto;
  padding-left: 24px;
  padding-right: 24px;
  padding-bottom: 60px;
  position: relative;
}

.post-article-container {
  min-width: 0;
}

/* TOC Styles */
.post-toc-container {
  position: fixed;
  top: calc(var(--navbar-height) + 40px);
  right: 40px;
  width: 260px;
  max-height: calc(100vh - var(--navbar-height) - 80px);
  overflow-y: auto;
}

.post-toc-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--color-text-primary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.post-toc-list {
  list-style: none;
  padding: 0;
  margin: 0;
  font-size: 0.85rem;
}

.post-toc-list li {
  margin-bottom: 8px;
}

.post-toc-list a {
  color: var(--color-text-secondary);
  text-decoration: none;
  display: block;
  line-height: 1.4;
  transition: color var(--transition-fast), border-color var(--transition-fast);
  border-left: 2px solid transparent;
  padding-left: 10px;
  margin-left: -12px;
}

.post-toc-list a:hover {
  color: var(--color-accent);
}

.post-toc-list a.active {
  color: var(--color-accent);
  border-left-color: var(--color-accent);
  font-weight: 500;
}

.toc-h1, .toc-h2 {
  padding-left: 0;
}

.toc-h3 {
  padding-left: 16px;
}

.toc-h4 {
  padding-left: 32px;
}

.toc-h5, .toc-h6 {
  padding-left: 48px;
}

.mobile-toc-toggle {
  display: none;
  position: fixed;
  bottom: 90px;
  right: 24px;
  height: 42px;
  padding: 0 16px;
  border-radius: 21px;
  background-color: var(--color-bg-card);
  color: var(--color-accent);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
  cursor: pointer;
  z-index: 998;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.mobile-toc-toggle:active {
  transform: scale(0.96);
}

@media (max-width: 1360px) {
  .mobile-toc-toggle.visible {
    display: flex;
  }

  .post-toc-container {
    display: none;
    position: fixed;
    bottom: 144px;
    right: 24px;
    width: 280px;
    max-height: 55vh;
    background-color: var(--color-bg-card);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    padding: 20px;
    z-index: 1001;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    transform: translateY(12px);
    opacity: 0;
    transition: opacity 0.25s ease, transform 0.25s ease;
    overflow-y: auto;
  }

  .post-toc-container.open {
    display: block !important;
    opacity: 1;
    transform: translateY(0);
  }
}

.post-header {
  margin-bottom: 40px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--color-border);
}

.post-title {
  font-size: 2.25rem;
  font-weight: 800;
  line-height: 1.3;
  margin-bottom: 16px;
}

.post-meta {
  display: flex;
  gap: 16px;
  align-items: center;
  flex-wrap: wrap;
  font-size: 0.9rem;
  color: var(--color-text-secondary);
}

.post-meta .meta-category {
  color: var(--color-accent);
  font-weight: 600;
}

.post-nav {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--color-border);
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--color-accent);
  text-decoration: none;
  font-weight: 500;
  transition: opacity var(--transition-fast);
}

.back-link:hover {
  opacity: 0.8;
}

@media (max-width: 767px) {
  .post-page {
    padding-left: 16px;
    padding-right: 16px;
    padding-top: calc(var(--navbar-height) + 20px);
    padding-bottom: 40px;
  }
  .post-title {
    font-size: 1.65rem;
    line-height: 1.35;
  }
  .post-meta {
    font-size: 0.8rem;
    gap: 8px;
  }
  .post-header {
    margin-bottom: 24px;
    padding-bottom: 16px;
  }
}

/* ==========================================================================
   12. Markdown Content Styles (.post-content / .markdown-body)
   ========================================================================== */

.post-content p,
.markdown-body p {
  margin-bottom: 1.5em;
  line-height: 1.8;
}

.post-content h1,
.post-content h2,
.post-content h3,
.post-content h4,
.post-content h5,
.post-content h6,
.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4,
.markdown-body h5,
.markdown-body h6 {
  font-weight: 700;
  margin-top: 2em;
  margin-bottom: 1em;
  color: var(--color-text-primary);
}

.post-content h1, .markdown-body h1 {
  font-size: 2rem;
}

.post-content h2, .markdown-body h2 {
  font-size: 1.5rem;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--color-border);
}

.post-content h3, .markdown-body h3 {
  font-size: 1.25rem;
}

.post-content h4, .markdown-body h4 {
  font-size: 1.1rem;
}

.post-content a,
.markdown-body a {
  color: var(--color-accent);
  text-decoration: underline;
  transition: opacity var(--transition-fast);
}

.post-content a:hover,
.markdown-body a:hover {
  opacity: 0.8;
}

.post-content strong,
.markdown-body strong {
  font-weight: 700;
  color: var(--color-text-primary);
}

.post-content em,
.markdown-body em {
  font-style: italic;
}

.post-content ul,
.post-content ol,
.markdown-body ul,
.markdown-body ol {
  padding-left: 2em;
  margin-bottom: 1.5em;
}

.post-content li,
.markdown-body li {
  margin-bottom: 0.5em;
  line-height: 1.7;
}

.post-content blockquote,
.markdown-body blockquote {
  border-left: 4px solid var(--color-accent);
  padding: 16px 20px;
  margin: 1.5em 0;
  background-color: var(--color-accent-light);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  color: var(--color-text-secondary);
  font-style: italic;
}

.post-content blockquote p,
.markdown-body blockquote p {
  margin-bottom: 0;
}

.post-content code,
.markdown-body code {
  background-color: var(--color-bg-secondary);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.85em;
  font-family: var(--font-mono);
  color: var(--color-accent);
}

.post-content pre,
.markdown-body pre {
  background-color: var(--color-code-bg);
  border-radius: var(--radius-md);
  padding: 20px;
  overflow-x: auto;
  margin: 1.5em 0;
  border: 1px solid var(--color-border);
}

.post-content pre code,
.markdown-body pre code {
  background-color: transparent;
  padding: 0;
  font-size: 0.85rem;
  line-height: 1.6;
  color: var(--color-text-primary);
}

.post-content table,
.markdown-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5em 0;
}

.post-content th,
.markdown-body th {
  background-color: var(--color-bg-secondary);
  padding: 12px 16px;
  text-align: left;
  font-weight: 600;
  border-bottom: 2px solid var(--color-border);
}

.post-content td,
.markdown-body td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--color-border);
}

.post-content tr:hover,
.markdown-body tr:hover {
  background-color: var(--color-accent-light);
}

.post-content img,
.markdown-body img {
  max-width: 100%;
  border-radius: var(--radius-md);
  margin: 1.5em 0;
}

.post-content hr,
.markdown-body hr {
  border: none;
  height: 1px;
  background-color: var(--color-border);
  margin: 2em 0;
}

/* ==========================================================================
   13. Animations
   ========================================================================== */

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeInUp 0.6s ease both;
}

.fade-in-delay-1 { animation-delay: 0.1s; }
.fade-in-delay-2 { animation-delay: 0.2s; }
.fade-in-delay-3 { animation-delay: 0.3s; }

/* ==========================================================================
   14. Empty State
   ========================================================================== */

.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--color-text-secondary);
}

.empty-state-icon {
  font-size: 3rem;
  margin-bottom: 16px;
  opacity: 0.5;
}

.empty-state-text {
  font-size: 1.1rem;
}

/* ==========================================================================
   15. Loading State
   ========================================================================== */

.loading {
  text-align: center;
  padding: 60px 20px;
  color: var(--color-text-secondary);
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.loading-spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto 16px;
}

/* ==========================================================================
   16. Footer
   ========================================================================== */

.footer {
  padding: 24px;
  text-align: center;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  border-top: 1px solid var(--color-border);
  margin-top: 40px;
}

/* ==========================================================================
   17. Utility
   ========================================================================== */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

.text-accent {
  color: var(--color-accent);
}

/* ==========================================================================
   18. Code Block Copy Button
   ========================================================================== */

.code-wrapper {
  position: relative;
}

.copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  background: var(--color-bg);
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 4px 8px;
  font-size: 12px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 4px;
  opacity: 0;
  transition: all var(--transition-fast);
  z-index: 10;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.code-wrapper:hover .copy-btn {
  opacity: 1;
}

.copy-btn:hover {
  background: var(--color-surface);
  color: var(--color-text-primary);
}

.copy-btn.copied {
  background: #10b981;
  color: white;
  border-color: #10b981;
  opacity: 1;
}

/* ==========================================================================
   19. Infinite Scroll / Loader
   ========================================================================== */

.loading-sentinel {
  width: 100%;
  display: flex;
}

.post-content table,
.markdown-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5em 0;
}

.post-content th,
.markdown-body th {
  background-color: var(--color-bg-secondary);
  padding: 12px 16px;
  text-align: left;
  font-weight: 600;
  border-bottom: 2px solid var(--color-border);
}

.post-content td,
.markdown-body td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--color-border);
}

.post-content tr:hover,
.markdown-body tr:hover {
  background-color: var(--color-accent-light);
}

.post-content img,
.markdown-body img {
  max-width: 100%;
  border-radius: var(--radius-md);
  margin: 1.5em 0;
}

.post-content hr,
.markdown-body hr {
  border: none;
  height: 1px;
  background-color: var(--color-border);
  margin: 2em 0;
}

/* ==========================================================================
   13. Animations
   ========================================================================== */

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeInUp 0.6s ease both;
}

.fade-in-delay-1 { animation-delay: 0.1s; }
.fade-in-delay-2 { animation-delay: 0.2s; }
.fade-in-delay-3 { animation-delay: 0.3s; }

/* ==========================================================================
   14. Empty State
   ========================================================================== */

.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--color-text-secondary);
}

.empty-state-icon {
  font-size: 3rem;
  margin-bottom: 16px;
  opacity: 0.5;
}

.empty-state-text {
  font-size: 1.1rem;
}

/* ==========================================================================
   15. Loading State
   ========================================================================== */

.loading {
  text-align: center;
  padding: 60px 20px;
  color: var(--color-text-secondary);
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.loading-spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto 16px;
}

/* ==========================================================================
   16. Footer
   ========================================================================== */

.footer {
  padding: 24px;
  text-align: center;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  border-top: 1px solid var(--color-border);
  margin-top: 40px;
}

/* ==========================================================================
   17. Utility
   ========================================================================== */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

.text-accent {
  color: var(--color-accent);
}

/* ==========================================================================
   18. Code Block Copy Button
   ========================================================================== */

.code-wrapper {
  position: relative;
}

.copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  background: var(--color-bg);
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 4px 8px;
  font-size: 12px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 4px;
  opacity: 0;
  transition: all var(--transition-fast);
  z-index: 10;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.code-wrapper:hover .copy-btn {
  opacity: 1;
}

.copy-btn:hover {
  background: var(--color-surface);
  color: var(--color-text-primary);
}

.copy-btn.copied {
  background: #10b981;
  color: white;
  border-color: #10b981;
  opacity: 1;
}

/* ==========================================================================
   19. Infinite Scroll / Loader
   ========================================================================== */

.loading-sentinel {
  width: 100%;
  display: flex;
  justify-content: center;
  padding: 40px 0;
  grid-column: 1 / -1;
}

.loader {
  width: 36px;
  height: 36px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-accent);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

.post-content table,
.markdown-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5em 0;
  display: block;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  max-width: 100%;
}

.post-content th,
.markdown-body th {
  background-color: var(--color-bg-secondary);
  padding: 12px 16px;
  text-align: left;
  font-weight: 600;
  border-bottom: 2px solid var(--color-border);
}

.post-content td,
.markdown-body td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--color-border);
}

.post-content tr:hover,
.markdown-body tr:hover {
  background-color: var(--color-accent-light);
}

.post-content img,
.markdown-body img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  margin: 1.5em 0;
  display: block;
}

.post-content hr,
.markdown-body hr {
  border: none;
  height: 1px;
  background-color: var(--color-border);
  margin: 2em 0;
}

/* KaTeX Display Formulas Mobile Scroll */
.katex-display {
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  padding: 8px 0;
  max-width: 100%;
}

/* ==========================================================================
   13. Animations
   ========================================================================== */

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeInUp 0.6s ease both;
}

.fade-in-delay-1 { animation-delay: 0.1s; }
.fade-in-delay-2 { animation-delay: 0.2s; }
.fade-in-delay-3 { animation-delay: 0.3s; }

/* ==========================================================================
   14. Empty State
   ========================================================================== */

.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--color-text-secondary);
}

.empty-state-icon {
  font-size: 3rem;
  margin-bottom: 16px;
  opacity: 0.5;
}

.empty-state-text {
  font-size: 1.1rem;
}

/* ==========================================================================
   15. Loading State
   ========================================================================== */

.loading {
  text-align: center;
  padding: 60px 20px;
  color: var(--color-text-secondary);
}

@keyframes spin {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

.loading-spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto 16px;
}

/* ==========================================================================
   16. Footer
   ========================================================================== */

.footer {
  padding: 24px;
  text-align: center;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  border-top: 1px solid var(--color-border);
  margin-top: 40px;
}

/* ==========================================================================
   17. Utility
   ========================================================================== */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

.text-accent {
  color: var(--color-accent);
}

/* ==========================================================================
   18. Code Block Copy Button
   ========================================================================== */

.code-wrapper {
  position: relative;
  max-width: 100%;
}

.copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  background: var(--color-bg-secondary);
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 4px 8px;
  font-size: 12px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 4px;
  opacity: 0;
  transition: all var(--transition-fast);
  z-index: 10;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.code-wrapper:hover .copy-btn {
  opacity: 1;
}

.copy-btn:hover {
  background: var(--color-accent-light);
  color: var(--color-accent);
}

@media (max-width: 600px) {
  .copy-btn {
    top: 6px;
    right: 6px;
    padding: 3px 6px;
    font-size: 11px;
    opacity: 0.85;
  }
  .post-content pre,
  .markdown-body pre {
    padding: 36px 14px 14px;
    font-size: 0.8rem;
    -webkit-overflow-scrolling: touch;
  }
}

/* ==========================================================================
   19. Infinite Scroll / Loader
   ========================================================================== */

.loading-sentinel {
  width: 100%;
  display: flex;
  justify-content: center;
  padding: 40px 0;
  grid-column: 1 / -1;
}

.loader {
  width: 36px;
  height: 36px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-accent);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

/* ==========================================================================
   20. Search Modal
   ========================================================================== */

.search-toggle {
  border: none;
  background: transparent;
  cursor: pointer;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-primary);
  transition: background-color var(--transition-fast);
}

.search-toggle:hover {
  background-color: var(--color-bg-secondary);
}

.search-modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.4);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: 2000;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding-top: 10vh;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease;
}

.search-modal.active {
  opacity: 1;
  pointer-events: auto;
}

.search-modal-content {
  width: 90%;
  max-width: 640px;
  background: var(--color-bg-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--color-border);
  overflow: hidden;
  transform: translateY(-20px);
  transition: transform 0.2s ease;
}

.search-modal.active .search-modal-content {
  transform: translateY(0);
}

.search-header {
  display: flex;
  align-items: center;
  padding: 16px 24px;
  border-bottom: 1px solid var(--color-border);
  gap: 16px;
  color: var(--color-text-secondary);
}

.search-header input {
  flex: 1;
  border: none;
  background: transparent;
  font-size: 1.2rem;
  color: var(--color-text-primary);
  outline: none;
}

.search-close {
  background: transparent;
  border: none;
  font-size: 1.5rem;
  color: var(--color-text-secondary);
  cursor: pointer;
  padding: 4px;
}

.search-results {
  max-height: 60vh;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}

.search-result-item {
  display: block;
  padding: 16px 24px;
  text-decoration: none;
  border-bottom: 1px solid var(--color-border);
  transition: background-color var(--transition-fast);
}

.search-result-item:hover {
  background-color: var(--color-bg-secondary);
}

.search-result-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: 4px;
}

.search-result-meta {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
}

.search-empty {
  padding: 32px;
  text-align: center;
  color: var(--color-text-secondary);
}

@media (max-width: 640px) {
  .search-modal {
    padding-top: 0;
    align-items: flex-start;
  }
  .search-modal-content {
    width: 100%;
    height: 100%;
    max-width: 100%;
    border-radius: 0;
    border: none;
    display: flex;
    flex-direction: column;
  }
  .search-results {
    flex: 1;
    max-height: none;
  }
  .search-header {
    padding: 14px 16px;
  }
  .search-header input {
    font-size: 1.05rem;
  }
}

/* ==========================================================================
   21. Back to Top & Reading Progress
   ========================================================================== */

.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background-color: var(--color-accent);
  color: white;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
  z-index: 999;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background-color: var(--color-accent-hover);
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

@media (max-width: 767px) {
  .back-to-top {
    bottom: 24px;
    right: 24px;
    width: 42px;
    height: 42px;
  }
}

.reading-progress-container {
  position: fixed;
  top: var(--navbar-height);
  left: 0;
  width: 100%;
  height: 3px;
  background: transparent;
  z-index: 1000;
  pointer-events: none;
}

.reading-progress-bar {
  height: 100%;
  background: var(--color-accent);
  width: 0%;
  transition: width 0.1s ease-out;
}