/* ===== Reset & Base ===== */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* CS Study Academic Color Palette */
  --primary: #6366F1;
  --secondary: #1E293B;
  --background: #F8FAFC;
  --bg-card: #FFFFFF;
  --bg-code: #F1F5F9;
  --border: #E2E8F0;
  --text-primary: #1E293B;
  --text-secondary: #64748B;
  --text-heading: #0F172A;
  --accent-warm: #8B5CF6;
  --gradient: linear-gradient(135deg, #6366F1, #8B5CF6);
  --font-body: 'Pretendard', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  --max-width: 800px;
  --glow: 0 4px 20px rgba(99, 102, 241, 0.15), 0 2px 8px rgba(30, 27, 75, 0.08);
  --shadow-card: 0 2px 12px rgba(30, 27, 75, 0.06);
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  background: var(--background);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

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

a:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
  border-radius: 2px;
}

/* ===== Navigation ===== */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(248, 250, 252, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: none;
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text-heading);
}

.site-logo:hover {
  color: var(--primary);
}

.logo-icon {
  color: var(--primary);
  font-size: 1.3rem;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
}

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

/* ===== Main ===== */
.site-main {
  flex: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.5rem;
  width: 100%;
}

/* ===== Hero ===== */
.hero {
  text-align: center;
  padding: 3rem 0 2rem;
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-heading);
  margin-bottom: 0.5rem;
}

.hero-title::before {
  content: '🍯 ';
}

.hero-sub {
  color: var(--text-secondary);
  font-size: 1.1rem;
}

/* ===== Post Card List ===== */
.post-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.post-card {
  display: block;
  color: inherit;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--bg-card);
  box-shadow: var(--shadow-card);
  transition: border-color 0.3s, box-shadow 0.3s, transform 0.2s;
}

.post-card:hover {
  border-color: var(--primary);
  box-shadow: var(--glow);
  transform: translateY(-2px);
  color: inherit;
}

.post-card-inner {
  padding: 1.5rem;
}

.post-date {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.post-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-heading);
  margin: 0.4rem 0 0.6rem;
  line-height: 1.4;
  word-break: break-word;
  overflow-wrap: break-word;
}

.post-card-excerpt {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

.read-more {
  display: inline-block;
  margin-top: 0.75rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--primary);
}

.empty-state {
  text-align: center;
  padding: 4rem 0;
  color: var(--text-secondary);
}

/* ===== Tag Badges ===== */
.post-tag {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 600;
  padding: 0.2em 0.6em;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.tag-cs-study { background: rgba(99, 102, 241, 0.15); color: #4F46E5; }
.tag-os { background: rgba(239, 68, 68, 0.12); color: #DC2626; }
.tag-network { background: rgba(14, 165, 233, 0.12); color: #0284C7; }
.tag-database { background: rgba(34, 197, 94, 0.12); color: #16A34A; }
.tag-application { background: rgba(168, 85, 247, 0.12); color: #7C3AED; }
.tag-datastructure { background: rgba(245, 158, 11, 0.12); color: #D97706; }
.tag-algorithm { background: rgba(236, 72, 153, 0.12); color: #DB2777; }
.tag-tech { background: rgba(20, 184, 166, 0.12); color: #0D9488; }

.post-series {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-top: 0.3rem;
}

.post-news-count {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.post-card-meta-top {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.post-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 0.75rem;
}

.post-meta-top {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 0.5rem;
}

/* ===== Post Page ===== */
.post-header {
  margin-bottom: 2rem;
}

.back-link {
  display: inline-block;
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.back-link:hover {
  color: var(--primary);
}

.post-header .post-date {
  display: block;
  margin-bottom: 0.5rem;
}

.post-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-heading);
  line-height: 1.3;
  word-break: break-word;
  overflow-wrap: break-word;
}

/* ===== Post Thumbnail ===== */
.post-thumbnail {
  margin: 0 0 2rem;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow-card);
}

.post-thumbnail-img {
  width: 100%;
  height: auto;
  display: block;
  aspect-ratio: 1200 / 630;
  object-fit: cover;
}

/* ===== Post Content ===== */
.post-content {
  font-size: 1rem;
  line-height: 1.8;
}

.post-content h1,
.post-content h2,
.post-content h3,
.post-content h4 {
  color: var(--text-heading);
  margin: 2rem 0 1rem;
  line-height: 1.3;
  scroll-margin-top: 5rem;
}

.post-content h1 { font-size: 1.8rem; font-weight: 700; }
.post-content h2 { font-size: 1.5rem; font-weight: 700; }
.post-content h3 { font-size: 1.25rem; font-weight: 600; }
.post-content h4 { font-size: 1.1rem; font-weight: 600; }

.post-content h2 {
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--primary);
}

.post-content p {
  margin-bottom: 1.2rem;
}

.post-content ul,
.post-content ol {
  margin: 1rem 0;
  padding-left: 1.5rem;
}

.post-content li {
  margin-bottom: 0.4rem;
}

.post-content blockquote {
  border-left: 4px solid var(--primary);
  padding: 0.75rem 1rem;
  margin: 1.5rem 0;
  background: var(--bg-code);
  border-radius: 0 8px 8px 0;
  color: var(--text-secondary);
}

.post-content img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  margin: 1.5rem 0;
}

.post-content a:not(.toc-link) {
  color: var(--secondary);
  font-weight: 500;
  border-bottom: 2px solid var(--primary);
  transition: border-color 0.2s, color 0.2s;
}

.post-content a:hover {
  color: var(--primary);
  border-bottom-color: var(--accent-warm);
}

/* ===== Code Blocks ===== */
.post-content code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--bg-code);
  color: var(--secondary);
  padding: 0.15em 0.4em;
  border-radius: 4px;
}

.post-content pre {
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.2rem;
  overflow-x: auto;
  margin: 1.5rem 0;
  position: relative;
}

.post-content pre code {
  background: none;
  padding: 0;
  font-size: 0.85rem;
  color: var(--text-primary);
  line-height: 1.6;
}

/* Code copy button */
.code-copy-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  padding: 0.25rem 0.6rem;
  font-size: 0.7rem;
  font-family: var(--font-mono);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text-secondary);
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.2s, background 0.2s;
}

.post-content pre:hover .code-copy-btn {
  opacity: 1;
}

.code-copy-btn:hover {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

/* Code block language label */
.post-content pre[class*="language-"]::before,
.post-content .highlight pre::before {
  content: attr(data-lang);
  position: absolute;
  top: 0;
  left: 1rem;
  padding: 0.1rem 0.5rem;
  font-size: 0.65rem;
  font-family: var(--font-mono);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
  background: var(--border);
  border-radius: 0 0 4px 4px;
}

/* ===== Mermaid Diagrams ===== */
.mermaid {
  margin: 1.5rem 0;
  padding: 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  text-align: center;
  overflow-x: auto;
}

pre.mermaid {
  border: none;
  background: var(--bg-card);
}

/* ===== Tables ===== */
.post-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  display: block;
  overflow-x: auto;
}

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

.post-content th {
  background: var(--primary);
  color: white;
  font-weight: 600;
}

.post-content hr {
  border: none;
  border-top: 2px solid var(--border);
  margin: 2rem 0;
}

/* ===== Post Footer ===== */
.post-footer {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}

/* ===== Site Footer ===== */
.site-footer {
  border-top: 1px solid var(--border);
  margin-top: auto;
  background: var(--secondary);
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.5rem;
  text-align: center;
  color: rgba(248, 250, 252, 0.8);
  font-size: 0.85rem;
}

/* ===== Search Button ===== */
.search-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0.75rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-secondary);
  cursor: pointer;
  font-family: var(--font-body);
  font-size: 0.9rem;
  transition: all 0.2s ease;
}

.search-btn:hover {
  border-color: var(--primary);
  color: var(--text-primary);
  box-shadow: var(--shadow-card);
}

.search-btn:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

.search-shortcut {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 0.15em 0.4em;
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text-secondary);
}

/* ===== Search Modal ===== */
.search-modal {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 10vh 1rem;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.2s ease, visibility 0.2s ease;
}

.search-modal.active {
  opacity: 1;
  visibility: visible;
}

.search-modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(15, 23, 42, 0.6);
  backdrop-filter: blur(4px);
}

.search-modal-container {
  position: relative;
  width: 100%;
  max-width: 600px;
  max-height: 80vh;
  background: var(--bg-card);
  border-radius: 16px;
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  overflow: hidden;
  transform: translateY(-20px);
  transition: transform 0.2s ease;
}

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

.search-modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border);
  background: var(--background);
}

.search-modal-title {
  font-weight: 600;
  color: var(--text-heading);
}

.search-modal-close {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: transparent;
  border: none;
  border-radius: 8px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s;
}

.search-modal-close:hover {
  background: var(--bg-code);
  color: var(--text-primary);
}

#search-container {
  padding: 1rem;
  max-height: calc(80vh - 60px);
  overflow-y: auto;
}

/* ===== Pagefind UI Customization ===== */
.pagefind-ui {
  --pagefind-ui-scale: 1;
  --pagefind-ui-primary: var(--primary);
  --pagefind-ui-text: var(--text-primary);
  --pagefind-ui-background: var(--bg-card);
  --pagefind-ui-border: var(--border);
  --pagefind-ui-tag: var(--bg-code);
  --pagefind-ui-border-width: 1px;
  --pagefind-ui-border-radius: 8px;
  --pagefind-ui-font: var(--font-body);
}

.pagefind-ui__search-input {
  font-family: var(--font-body) !important;
  font-size: 1rem !important;
  padding: 0.75rem 1rem 0.75rem 2.5rem !important;
  border-radius: 8px !important;
  border: 2px solid var(--border) !important;
  background: var(--background) !important;
  transition: border-color 0.2s, box-shadow 0.2s !important;
}

.pagefind-ui__search-input:focus {
  border-color: var(--primary) !important;
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2) !important;
  outline: none !important;
}

.pagefind-ui__search-clear {
  background: var(--text-secondary) !important;
}

.pagefind-ui__search-clear:hover {
  background: var(--text-primary) !important;
}

.pagefind-ui__result {
  padding: 1rem !important;
  margin-bottom: 0.75rem !important;
  border: 1px solid var(--border) !important;
  border-radius: 12px !important;
  background: var(--bg-card) !important;
  transition: border-color 0.2s, box-shadow 0.2s, transform 0.2s !important;
}

.pagefind-ui__result:hover {
  border-color: var(--primary) !important;
  box-shadow: var(--glow) !important;
  transform: translateY(-1px) !important;
}

.pagefind-ui__result-link {
  color: var(--text-heading) !important;
  font-weight: 600 !important;
  font-size: 1.05rem !important;
  text-decoration: none !important;
}

.pagefind-ui__result-link:hover {
  color: var(--primary) !important;
}

.pagefind-ui__result-excerpt {
  color: var(--text-secondary) !important;
  font-size: 0.9rem !important;
  line-height: 1.6 !important;
  margin-top: 0.5rem !important;
}

.pagefind-ui__result-excerpt mark {
  background: rgba(99, 102, 241, 0.2) !important;
  color: var(--text-heading) !important;
  padding: 0.1em 0.2em !important;
  border-radius: 3px !important;
}

.pagefind-ui__message {
  font-family: var(--font-body) !important;
  color: var(--text-secondary) !important;
  padding: 2rem !important;
  text-align: center !important;
}

.pagefind-ui__button {
  background: var(--primary) !important;
  color: white !important;
  border-radius: 8px !important;
  font-weight: 600 !important;
  transition: background 0.2s !important;
}

.pagefind-ui__button:hover {
  background: var(--accent-warm) !important;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .hero {
    padding: 2rem 0 1.5rem;
  }

  .hero-title {
    font-size: 2rem;
  }

  .post-card-title {
    font-size: 1.1rem;
  }
}

@media (max-width: 640px) {
  .hero-title {
    font-size: 1.8rem;
  }

  .post-title {
    font-size: 1.5rem;
  }

  .post-card-inner {
    padding: 1.2rem;
  }

  .post-card-title {
    font-size: 1rem;
  }

  .post-content pre {
    padding: 0.8rem;
  }

  .post-list {
    gap: 0.75rem;
  }

  .search-shortcut {
    display: none;
  }

  .search-btn {
    padding: 0.5rem;
  }

  .search-modal {
    padding: 5vh 0.75rem;
  }

  .search-modal-container {
    max-height: 90vh;
    border-radius: 12px;
  }
}

/* ===== Post Navigation (Prev/Next) ===== */
.post-navigation {
  display: flex;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}

.post-nav-link {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  padding: 1rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  transition: all 0.2s ease;
}

.post-nav-link:hover {
  border-color: var(--primary);
  box-shadow: var(--glow);
  transform: translateY(-2px);
}

.post-nav-prev { text-align: left; }
.post-nav-next { text-align: right; }

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

.nav-title {
  font-weight: 600;
  color: var(--text-heading);
  line-height: 1.4;
}

.post-nav-placeholder {
  flex: 1;
}

/* ===== Related Posts ===== */
.related-posts {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}

.related-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-heading);
  margin-bottom: 1.25rem;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1rem;
}

.related-card {
  display: block;
  padding: 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 10px;
  transition: all 0.2s ease;
}

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

.related-card-inner {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.related-date {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.related-card-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-heading);
  line-height: 1.4;
}

.related-tags {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
  margin-top: 0.3rem;
}

/* ===== Page Header (Tags/Archive) ===== */
.page-header {
  margin-bottom: 2rem;
}

.page-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-heading);
  margin: 0.5rem 0;
}

.page-desc {
  color: var(--text-secondary);
  font-size: 1rem;
}

/* ===== Tags Page ===== */
.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 2.5rem;
  padding: 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
}

.tag-cloud-item {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: 20px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-primary);
  transition: all 0.2s ease;
}

.tag-cloud-item:hover {
  border-color: var(--primary);
  background: var(--bg-card);
  color: var(--primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-card);
}

.tag-count {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 1.5rem;
  height: 1.5rem;
  padding: 0 0.4rem;
  background: var(--primary);
  color: white;
  border-radius: 10px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
}

.tags-list {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.tag-section {
  padding: 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
}

.tag-section-title {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.tag-badge {
  padding: 0.3em 0.8em;
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
}

.tag-section-count {
  font-size: 0.85rem;
  font-weight: 400;
  color: var(--text-secondary);
}

.tag-posts-list {
  list-style: none;
  padding: 0;
}

.tag-post-item a {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--border);
  color: var(--text-primary);
}

.tag-post-item:last-child a {
  border-bottom: none;
}

.tag-post-item a:hover {
  color: var(--primary);
}

.tag-post-title {
  flex: 1;
  font-weight: 500;
}

.tag-post-date {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.tag-post-more a {
  display: inline-block;
  margin-top: 0.75rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--primary);
}

/* ===== Archive Page ===== */
.archive-stats {
  display: flex;
  gap: 2rem;
  margin-bottom: 2rem;
  padding: 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
}

.stat-item {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.stat-number {
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary);
  font-family: var(--font-mono);
}

.stat-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.archive-timeline {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.archive-year {
  padding: 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
}

.year-title {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding-bottom: 1rem;
  border-bottom: 2px solid var(--primary);
  margin-bottom: 1rem;
}

.year-label {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-heading);
}

.year-count {
  font-size: 0.85rem;
  font-weight: 400;
  color: var(--text-secondary);
}

.archive-month {
  margin-bottom: 1.5rem;
}

.archive-month:last-child {
  margin-bottom: 0;
}

.month-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-heading);
  margin-bottom: 0.75rem;
  padding-left: 0.5rem;
  border-left: 3px solid var(--primary);
}

.month-count {
  font-weight: 400;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.archive-posts {
  list-style: none;
  padding: 0;
}

.archive-post-item {
  margin-bottom: 0.4rem;
}

.archive-post-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 0.75rem;
  border-radius: 8px;
  color: var(--text-primary);
  transition: background 0.2s;
}

.archive-post-link:hover {
  background: var(--bg-code);
  color: var(--primary);
}

.archive-date {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
  min-width: 2.5rem;
}

.archive-title {
  flex: 1;
  font-weight: 500;
}

/* Tag Archive Page */
.tag-archive-page .page-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* Clickable post tags */
a.post-tag {
  transition: transform 0.2s, box-shadow 0.2s;
}

a.post-tag:hover {
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

/* ===== Reading Time ===== */
.reading-time {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.reading-time-icon {
  opacity: 0.7;
}

/* ===== Reading Progress Bar ===== */
.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  z-index: 200;
  background: transparent;
}

.reading-progress-bar {
  height: 100%;
  width: 0%;
  background: var(--gradient);
  transition: width 0.1s linear;
  border-radius: 0 2px 2px 0;
}

/* ===== Post Layout with ToC ===== */
.post-layout {
  position: relative;
  max-width: var(--max-width);
  margin: 0 auto;
}

/* ===== ToC Sidebar (Desktop) ===== */
.toc-sidebar {
  display: none;
}

@media (min-width: 1200px) {
  .site-main:has(.post-layout) {
    max-width: calc(var(--max-width) + 240px + 2rem);
  }

  .post-layout {
    max-width: none;
    display: grid;
    grid-template-columns: 240px minmax(0, var(--max-width));
    gap: 2rem;
  }

  .toc-sidebar {
    display: block;
    position: relative;
  }

  .toc-nav {
    position: sticky;
    top: 5rem;
    max-height: calc(100vh - 7rem);
    overflow-y: auto;
    padding: 1rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    box-shadow: var(--shadow-card);
    scrollbar-width: thin;
    scrollbar-color: var(--border) transparent;
  }

  .toc-nav::-webkit-scrollbar {
    width: 4px;
  }

  .toc-nav::-webkit-scrollbar-track {
    background: transparent;
  }

  .toc-nav::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 2px;
  }
}

.toc-title {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-heading);
  margin-bottom: 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--primary);
}

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

.toc-item {
  margin-bottom: 0.15rem;
}

.toc-item.toc-sub {
  padding-left: 1rem;
}

.toc-link {
  display: block;
  padding: 0.35rem 0.6rem;
  font-size: 0.82rem;
  line-height: 1.4;
  color: var(--text-secondary);
  border-left: 2px solid transparent;
  border-radius: 0 4px 4px 0;
  transition: all 0.2s ease;
  text-decoration: none;
  border-bottom: none !important;
}

.toc-link:hover {
  color: var(--text-primary);
  background: var(--bg-code);
  border-bottom: none !important;
}

.toc-link.active {
  color: var(--primary);
  font-weight: 600;
  border-left-color: var(--primary);
  background: rgba(99, 102, 241, 0.08);
}

/* ===== Mobile ToC Button ===== */
.toc-mobile-btn {
  display: none;
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 90;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: none;
  background: var(--secondary);
  color: var(--background);
  box-shadow: 0 4px 16px rgba(15, 23, 42, 0.3);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  transition: transform 0.2s, box-shadow 0.2s;
}

.toc-mobile-btn:hover {
  transform: scale(1.05);
  box-shadow: 0 6px 20px rgba(15, 23, 42, 0.4);
}

.toc-mobile-btn:active {
  transform: scale(0.95);
}

@media (max-width: 1199px) {
  .toc-mobile-btn {
    display: flex;
  }
}

/* ===== Mobile ToC Bottom Sheet ===== */
.toc-mobile-sheet {
  position: fixed;
  inset: 0;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.25s ease, visibility 0.25s ease;
}

.toc-mobile-sheet.active {
  opacity: 1;
  visibility: visible;
}

.toc-mobile-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(15, 23, 42, 0.5);
  backdrop-filter: blur(4px);
}

.toc-mobile-content {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  max-height: 70vh;
  background: var(--bg-card);
  border-radius: 16px 16px 0 0;
  box-shadow: 0 -4px 24px rgba(0, 0, 0, 0.15);
  transform: translateY(100%);
  transition: transform 0.3s cubic-bezier(0.32, 0.72, 0, 1);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.toc-mobile-sheet.active .toc-mobile-content {
  transform: translateY(0);
}

.toc-mobile-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.toc-mobile-title {
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-heading);
}

.toc-mobile-close {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: transparent;
  border: none;
  border-radius: 8px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s;
}

.toc-mobile-close:hover {
  background: var(--bg-code);
  color: var(--text-primary);
}

.toc-mobile-list {
  padding: 1rem 1.25rem;
  overflow-y: auto;
  flex: 1;
}

.toc-mobile-list .toc-link {
  padding: 0.5rem 0.75rem;
  font-size: 0.9rem;
}

/* ===== Mobile Responsive (Tags/Archive/Navigation) ===== */
@media (max-width: 640px) {
  .post-navigation {
    flex-direction: column;
  }

  .post-nav-next {
    text-align: left;
  }

  .related-grid {
    grid-template-columns: 1fr;
  }

  .tag-cloud {
    padding: 1rem;
  }

  .tag-cloud-item {
    padding: 0.4rem 0.75rem;
    font-size: 0.85rem;
  }

  .archive-stats {
    gap: 1.5rem;
  }

  .stat-number {
    font-size: 1.5rem;
  }

  .page-title {
    font-size: 1.5rem;
  }
}

/* ===== Home Layout with Category Sidebar ===== */
.home-layout {
  position: relative;
  max-width: var(--max-width);
  margin: 0 auto;
}

.category-sidebar {
  display: none;
}

@media (min-width: 1200px) {
  .site-main:has(.home-layout) {
    max-width: calc(var(--max-width) + 240px + 2rem);
  }

  .home-layout {
    max-width: none;
    display: grid;
    grid-template-columns: 240px minmax(0, var(--max-width));
    gap: 2rem;
  }

  .category-sidebar {
    display: block;
    position: relative;
  }

  .category-nav {
    position: sticky;
    top: 5rem;
    max-height: calc(100vh - 7rem);
    overflow-y: auto;
    padding: 1rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    box-shadow: var(--shadow-card);
    scrollbar-width: thin;
    scrollbar-color: var(--border) transparent;
  }
}

.category-title {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-heading);
  margin-bottom: 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--primary);
}

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

.category-item {
  margin-bottom: 0.15rem;
}

.category-link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 0.4rem 0.6rem;
  font-size: 0.85rem;
  line-height: 1.4;
  color: var(--text-secondary);
  background: none;
  border: none;
  border-left: 2px solid transparent;
  border-radius: 0 4px 4px 0;
  cursor: pointer;
  font-family: var(--font-body);
  transition: all 0.2s ease;
}

.category-link:hover {
  color: var(--text-primary);
  background: var(--bg-code);
}

.category-link.active {
  color: var(--primary);
  font-weight: 600;
  border-left-color: var(--primary);
  background: rgba(99, 102, 241, 0.08);
}

.category-count {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 1.4rem;
  height: 1.4rem;
  padding: 0 0.35rem;
  background: var(--bg-code);
  border-radius: 8px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--text-secondary);
}

.category-link.active .category-count {
  background: var(--primary);
  color: white;
}

/* ===== Mobile Category Bar ===== */
.category-mobile-bar {
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  padding: 0 1.5rem 1rem;
  max-width: var(--max-width);
  margin: 0 auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}

.category-mobile-bar::-webkit-scrollbar {
  display: none;
}

@media (min-width: 1200px) {
  .category-mobile-bar {
    display: none;
  }
}

.category-chip {
  flex-shrink: 0;
  padding: 0.4rem 0.9rem;
  font-size: 0.82rem;
  font-weight: 500;
  font-family: var(--font-body);
  color: var(--text-secondary);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 20px;
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
}

.category-chip:hover {
  border-color: var(--primary);
  color: var(--text-primary);
}

.category-chip.active {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
  font-weight: 600;
}

/* ===== Pagination ===== */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.35rem;
  margin-top: 2rem;
  padding: 1rem 0;
}

.pagination-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.2rem;
  height: 2.2rem;
  padding: 0 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.pagination-link:hover {
  border-color: var(--primary);
  color: var(--text-primary);
  box-shadow: var(--shadow-card);
}

.pagination-link.active {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
  font-weight: 700;
}

.pagination-prev,
.pagination-next {
  font-family: var(--font-body);
  font-size: 0.82rem;
  padding: 0 0.75rem;
}