/* ============================================
   Blog Theme - Modern Minimal with Dark/Light
   ============================================ */

/* --- CSS Custom Properties --- */
:root {
  /* Light theme (Tokyo Day) - default */
  --bg-primary: #ffffff;
  --bg-secondary: #f6f7fb;
  --bg-tertiary: #e8eaf2;
  --bg-code: #f6f7fb;
  --bg-code-block: #f3f4f8;
  --text-primary: #1a1a2e;
  --text-secondary: #4a4a6a;
  --text-tertiary: #6b7280;
  --text-code: #3760bf;

  /* Syntax highlighting (Tokyo Day - light) */
  --syntax-comment: #848cb5;
  --syntax-keyword: #c91b6e;
  --syntax-string:  #587539;
  --syntax-name:    #007197;
  --syntax-fn:      #2e7de9;
  --syntax-number:  #9854f1;
  --syntax-text:    #3760bf;
  --syntax-builtin: #007197;
  --syntax-deleted: #c64343;
  --syntax-added:   #587539;
  --syntax-lineno:  #a8aecb;
  --accent: #34548a;
  --accent-hover: #283655;
  --accent-light: rgba(52,84,138,0.10);
  --border: #e5e7eb;
  --border-light: #f0f0f0;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07);
  --shadow-lg: 0 10px 25px rgba(0,0,0,0.1);
  --tag-bg: rgba(52,84,138,0.13);
  --tag-text: #34548a;
  --nav-bg: rgba(255,255,255,0.85);
  --scrollbar-track: #f1f3f9;
  --scrollbar-thumb: #c7cde0;
  --scrollbar-thumb-hover: #aab3cc;
  --radius: 8px;
  --radius-lg: 12px;
  --transition: 0.2s ease;
  --content-width: 720px;
  --wide-width: 1080px;

  /* Viz palette (consumed by canvas demos via window.Viz.colors()).
     Edit these to retune all 30+ interactive visualizations site-wide. */
  --viz-green:  #16a34a;
  --viz-orange: #d97706;
  --viz-pink:   #ec4899;
  --viz-red:    #dc2626;
  --viz-cyan:   #0891b2;
  --viz-yellow: #facc15;
  --viz-grid:   #e5e7eb;
  --viz-muted:  #6b7280;
}

[data-theme="dark"] {
  /* Dark theme (Tokyo Night, deepened) */
  --bg-primary: #12131a;
  --bg-secondary: #1a1b26;
  --bg-tertiary: #24283b;
  --bg-code: #1a1b26;
  --bg-code-block: #0d0e14;
  --text-primary: #ededf0;
  --text-secondary: #b0b0c0;
  --text-tertiary: #7a7a92;
  --text-code: #ededf0;

  /* Syntax highlighting (Dracula - dark) */
  --syntax-comment: #6272a4;
  --syntax-keyword: #ff79c6;
  --syntax-string:  #f1fa8c;
  --syntax-name:    #8be9fd;
  --syntax-fn:      #50fa7b;
  --syntax-number:  #bd93f9;
  --syntax-text:    #f8f8f2;
  --syntax-builtin: #8be9fd;
  --syntax-deleted: #ff5555;
  --syntax-added:   #50fa7b;
  --syntax-lineno:  #44475a;
  --accent: #5d8de8;
  --accent-hover: #7fa3f0;
  --accent-light: rgba(93,141,232,0.16);
  --border: #24283b;
  --border-light: #1a1b26;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.2);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.3);
  --shadow-lg: 0 10px 25px rgba(0,0,0,0.4);
  --tag-bg: rgba(93,141,232,0.16);
  --tag-text: #7fa3f0;
  --nav-bg: rgba(18,19,26,0.9);
  --scrollbar-track: #12131a;
  --scrollbar-thumb: #3b4261;
  --scrollbar-thumb-hover: #565f89;

  /* Viz palette (dark variants) */
  --viz-green:  #9ece6a;
  --viz-orange: #ff9e64;
  --viz-pink:   #f9a8d4;
  --viz-red:    #f7768e;
  --viz-cyan:   #7dcfff;
  --viz-yellow: #fde047;
  --viz-grid:   #24283b;
  --viz-muted:  #565f89;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  font-size: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  line-height: 1.7;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: background-color var(--transition), color var(--transition);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition);
}

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

img {
  max-width: 100%;
  height: auto;
}

/* --- Scrollbars (Global) --- */
* {
  scrollbar-width: thin;
  scrollbar-color: var(--scrollbar-thumb) var(--scrollbar-track);
}

*::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

*::-webkit-scrollbar-track {
  background: var(--scrollbar-track);
}

*::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: 999px;
  border: 2px solid var(--scrollbar-track);
  background-clip: padding-box;
}

*::-webkit-scrollbar-thumb:hover {
  background: var(--scrollbar-thumb-hover);
  border-color: var(--scrollbar-track);
}

*::-webkit-scrollbar-corner {
  background: var(--scrollbar-track);
}

/* --- Form Controls --- */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 4px;
  border-radius: 999px;
  background: var(--border);
  outline: none;
  transition: background-color var(--transition);
}

input[type="range"]::-webkit-slider-runnable-track {
  height: 4px;
  border-radius: 999px;
  background: var(--border);
}

input[type="range"]::-moz-range-track {
  height: 4px;
  border-radius: 999px;
  background: var(--border);
  border: none;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 2px solid var(--bg-primary);
  background: var(--accent);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  margin-top: -5px;
}

input[type="range"]::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 2px solid var(--bg-primary);
  background: var(--accent);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
}

[data-theme="dark"] input[type="range"] {
  background: var(--bg-tertiary);
}

[data-theme="dark"] input[type="range"]::-webkit-slider-runnable-track,
[data-theme="dark"] input[type="range"]::-moz-range-track {
  background: var(--bg-tertiary);
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--text-primary);
  margin-top: 2em;
  margin-bottom: 0.5em;
}

h1 { font-size: clamp(1.75rem, 1.5rem + 1.25vw, 2.5rem); }
h2 { font-size: clamp(1.4rem, 1.2rem + 1vw, 1.875rem); }
h3 { font-size: clamp(1.15rem, 1rem + 0.75vw, 1.5rem); }
h4 { font-size: clamp(1.05rem, 1rem + 0.25vw, 1.25rem); }

p {
  margin-bottom: 1.25em;
}

blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.75em 1.25em;
  margin: 1.5em 0;
  background: var(--bg-secondary);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--text-secondary);
  font-style: italic;
}

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

hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2em 0;
}

/* --- Layout --- */
.container {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.content-wrapper {
  max-width: var(--content-width);
  margin: 0 auto;
}

/* --- Navigation --- */
.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background-color var(--transition), border-color var(--transition);
}

.nav-inner {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.nav-brand {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.nav-brand:hover {
  color: var(--accent);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  padding: 0.4rem 0.75rem;
  border-radius: 6px;
  transition: color var(--transition), background-color var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
  background: var(--bg-secondary);
}

.nav-links a svg {
  width: 18px;
  height: 18px;
  vertical-align: middle;
}

/* Theme toggle */
.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  cursor: pointer;
  padding: 0.4rem;
  border-radius: 6px;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: color var(--transition), border-color var(--transition), background-color var(--transition);
  width: 34px;
  height: 34px;
}

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

.theme-toggle svg {
  width: 18px;
  height: 18px;
}

.theme-toggle .sun-icon { display: none; }
.theme-toggle .moon-icon { display: block; }
[data-theme="dark"] .theme-toggle .sun-icon { display: block; }
[data-theme="dark"] .theme-toggle .moon-icon { display: none; }

/* Mobile nav */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  color: var(--text-primary);
}

.nav-toggle svg {
  width: 24px;
  height: 24px;
}

@media (max-width: 640px) {
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 0.75rem 1.5rem;
    gap: 0.25rem;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    display: block;
    padding: 0.6rem 0.75rem;
  }
}

/* --- Profile Section (Home) --- */
.profile-section {
  padding: 6rem 0 3rem;
}

.profile-card {
  display: flex;
  align-items: flex-start;
  gap: 2rem;
  max-width: var(--content-width);
  margin: 0 auto;
}

.profile-avatar {
  width: 96px;
  height: 96px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
  border: 3px solid var(--border);
}

.profile-info {
  flex: 1;
}

.profile-name {
  font-size: 1.75rem;
  font-weight: 800;
  margin: 0 0 0.15rem;
  letter-spacing: -0.03em;
}

.profile-role {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
}

.profile-bio {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 1rem;
}

.profile-interests {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1rem;
}

.profile-interests span {
  font-size: 0.75rem;
  font-weight: 500;
  padding: 0.2rem 0.6rem;
  background: var(--tag-bg);
  color: var(--tag-text);
  border-radius: 100px;
}

.profile-links {
  display: flex;
  gap: 0.75rem;
}

.profile-links a {
  color: var(--text-tertiary);
  transition: color var(--transition);
}

.profile-links a:hover {
  color: var(--accent);
}

.profile-links svg {
  width: 20px;
  height: 20px;
}

/* --- Home Welcome Intro --- */
.welcome-intro {
  max-width: var(--content-width);
  margin: 4.5rem auto 1.5rem;
  display: flex;
  align-items: center;
  gap: 2rem;
  padding: 1.25rem 2.25rem;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
  border: 1px solid var(--border);
  position: relative;
  overflow: hidden;
}

.welcome-intro::before {
  content: '';
  position: absolute;
  top: -40%;
  right: -10%;
  width: 260px;
  height: 260px;
  background: var(--accent);
  opacity: 0.04;
  border-radius: 50%;
  pointer-events: none;
}

.welcome-avatar {
  width: 100px !important;
  height: 100px !important;
  max-width: 100px !important;
  max-height: 100px !important;
  border-radius: 50%;
  object-fit: cover;
  display: block;
  flex-shrink: 0;
  border: 2px solid var(--border);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.welcome-text {
  flex: 1;
  min-width: 0;
}

.welcome-name {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 0 0 0.35rem;
  line-height: 1.3;
}

.welcome-tagline {
  margin: 0 0 0.85rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

.welcome-links {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.welcome-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-tertiary);
  text-decoration: none;
  padding: 0.3rem 0.7rem;
  border-radius: 6px;
  background: var(--bg-primary);
  border: 1px solid var(--border);
  transition: color var(--transition), border-color var(--transition), background var(--transition);
}

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

.welcome-link svg {
  opacity: 0.7;
  transition: opacity var(--transition);
}

.welcome-link:hover svg {
  opacity: 1;
}

.welcome-email {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
}

.welcome-email:hover {
  text-decoration: underline;
}

@media (max-width: 640px) {
  .welcome-intro {
    margin-top: 4.5rem;
    flex-direction: column;
    text-align: center;
    padding: 1.75rem 1.25rem;
    gap: 1.25rem;
  }

  .welcome-links {
    justify-content: center;
  }

  .profile-card {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .profile-interests {
    justify-content: center;
  }

  .profile-links {
    justify-content: center;
  }
}

/* --- Post List --- */
.posts-section {
  padding: 1rem 0 4rem;
}

.posts-section-top {
  padding-top: 1rem;
}

.section-label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-tertiary);
  margin-bottom: 1.1rem;
  max-width: var(--content-width);
  margin-left: auto;
  margin-right: auto;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border);
}

.post-list {
  list-style: none;
  max-width: var(--content-width);
  margin: 0 auto;
}

.post-item {
  padding: 1.4rem 0;
  border-bottom: 1px solid var(--border-light);
}

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

.post-item-title {
  font-size: 1.2rem;
  font-weight: 700;
  margin: 0 0 0.4rem;
  letter-spacing: -0.01em;
  line-height: 1.4;
}

.post-item-title a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  color: var(--text-primary);
  transition: color var(--transition);
}

.post-item-title a:hover {
  color: var(--accent);
}

.post-item-title-text {
  flex: 1;
}

.post-item-open {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--accent);
  background: transparent;
  border: none;
  padding: 0;
  white-space: nowrap;
  opacity: 0.88;
}

.post-item-title a:hover .post-item-open {
  opacity: 1;
}

.post-item-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 0.7rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.post-series-preview {
  margin: 0.15rem 0 0.85rem;
  border: none;
  border-left: 2px solid var(--border);
  border-radius: 0;
  padding-left: 0.7rem;
  background: transparent;
}

.post-series-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.6rem;
  padding: 0 0 0.32rem;
  border-bottom: none;
  background: transparent;
}

.post-series-title {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
}

.post-series-count {
  font-size: 0.66rem;
  font-weight: 600;
  color: var(--text-tertiary);
  background: transparent;
  border: none;
  padding: 0;
}

.post-series-list {
  list-style: none;
  max-height: 130px;
  overflow-y: auto;
  padding-right: 0.45rem;
  scrollbar-gutter: stable;
  scrollbar-width: thin;
  scrollbar-color: var(--scrollbar-thumb) var(--scrollbar-track);
}

.post-series-list::-webkit-scrollbar {
  width: 7px;
  height: 7px;
}

.post-series-list::-webkit-scrollbar-track {
  background: var(--scrollbar-track);
}

.post-series-list::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: 999px;
  border: 1px solid var(--scrollbar-track);
}

.post-series-list::-webkit-scrollbar-thumb:hover {
  background: var(--scrollbar-thumb-hover);
}

.post-series-list li + li {
  border-top: none;
}

.post-series-list a {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.7rem;
  padding: 0.32rem 0;
  color: var(--text-secondary);
  transition: color var(--transition);
}

.post-series-list a:hover {
  background: transparent;
  color: var(--accent);
}

.post-series-list a span {
  font-size: 0.78rem;
  line-height: 1.35;
}

.post-series-list time {
  font-size: 0.68rem;
  color: var(--text-tertiary);
  white-space: nowrap;
  flex-shrink: 0;
}

@media (max-width: 640px) {
  .post-item {
    padding: 1.15rem 0;
  }

  .post-item-title a {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.45rem;
  }

  .post-series-list a {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.12rem;
  }
}

.post-item-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  font-size: 0.8rem;
  color: var(--text-tertiary);
}

.post-item-meta .dot {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--text-tertiary);
}

.post-item-tags {
  display: flex;
  gap: 0.35rem;
}

.post-item-tags a {
  font-size: 0.72rem;
  font-weight: 500;
  padding: 0.15rem 0.5rem;
  background: var(--tag-bg);
  color: var(--tag-text);
  border-radius: 100px;
  transition: background-color var(--transition);
}

.post-item-tags a:hover {
  background: var(--accent-light);
}

/* --- Pagination --- */
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  padding: 2rem 0;
  max-width: var(--content-width);
  margin: 0 auto;
}

.pagination a,
.pagination span {
  font-size: 0.85rem;
  font-weight: 500;
  padding: 0.4rem 1rem;
  border-radius: 6px;
  transition: all var(--transition);
}

.pagination a {
  color: var(--text-secondary);
  background: var(--bg-secondary);
}

.pagination a:hover {
  color: var(--text-primary);
  background: var(--bg-tertiary);
}

.pagination .current {
  color: var(--text-tertiary);
  font-size: 0.85rem;
}

/* --- Post Single --- */
.post-header {
  padding: 5rem 0 2rem;
  max-width: 1000px;
  margin: 0 auto;
}

.post-categories {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: 1rem;
}

.post-categories a {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0.2rem 0.6rem;
  background: var(--tag-bg);
  color: var(--tag-text);
  border-radius: 100px;
}

.post-title {
  font-size: clamp(1.75rem, 1.5rem + 1.25vw, 2.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin: 0 0 1rem;
  line-height: 1.2;
}

.post-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  font-size: 0.85rem;
  color: var(--text-tertiary);
}

.post-meta .author-avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  object-fit: cover;
}

.post-meta .dot {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--text-tertiary);
}

/* Post Layout (content + sidebar) */
.post-layout {
  display: grid;
  grid-template-columns: 1fr 220px;
  gap: 3rem;
  max-width: 1000px;
  margin: 0 auto;
  align-items: start;
}

@media (max-width: 900px) {
  .post-layout {
    grid-template-columns: 1fr;
  }

  .post-sidebar {
    display: none;
  }
}

/* Post Sidebar TOC */
.post-sidebar {
  position: relative;
  align-self: stretch;
}

.toc-sidebar {
  position: sticky;
  top: 80px;
  max-height: calc(100vh - 100px);
  overflow-y: auto;
  padding-right: 0.5rem;
  scrollbar-width: thin;
  scrollbar-color: var(--scrollbar-thumb) var(--scrollbar-track);
}

.toc-sidebar::-webkit-scrollbar {
  width: 8px;
}

.toc-sidebar::-webkit-scrollbar-track {
  background: var(--scrollbar-track);
}

.toc-sidebar::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: 999px;
  border: 2px solid var(--scrollbar-track);
  background-clip: padding-box;
}

.toc-sidebar::-webkit-scrollbar-thumb:hover {
  background: var(--scrollbar-thumb-hover);
}

.toc-sidebar .toc-title {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-tertiary);
  margin-bottom: 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}

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

.toc-list li {
  margin-bottom: 0.1rem;
}

.toc-list a {
  display: block;
  font-size: 0.78rem;
  line-height: 1.4;
  color: var(--text-tertiary);
  padding: 0.2rem 0 0.2rem 0.75rem;
  border-left: 2px solid transparent;
  text-decoration: none;
  transition: color var(--transition), border-color var(--transition);
}

.toc-list a:hover {
  color: var(--text-primary);
}

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

.toc-list .toc-h3 {
  padding-left: 1.5rem;
  font-size: 0.73rem;
}

.toc-list .toc-h4 {
  padding-left: 2.25rem;
  font-size: 0.7rem;
}

/* Post Comments */
.post-comments {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 2rem 0;
  border-top: 1px solid var(--border);
}

/* Post Content */
.post-content {
  max-width: var(--content-width);
  min-width: 0;
  padding-bottom: 3rem;
}

.post-content h1:first-child,
.post-content h2:first-child,
.post-content h3:first-child {
  margin-top: 1em;
}

.post-content a {
  text-decoration: underline;
  text-decoration-color: var(--accent-light);
  text-underline-offset: 3px;
  transition: text-decoration-color var(--transition);
}

.post-content a:hover {
  text-decoration-color: var(--accent);
}

.post-content img {
  border-radius: var(--radius);
  margin: 1.5em 0;
}

.post-content ul,
.post-content ol {
  padding-left: 1.5em;
  margin-bottom: 1.25em;
}

.post-content li {
  margin-bottom: 0.35em;
}

.post-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5em 0;
  font-size: 0.9rem;
  display: block;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

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

.post-content th {
  background: var(--bg-secondary);
  font-weight: 600;
}

/* Code */
.post-content code {
  font-family: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
  font-size: 0.85em;
  background: var(--bg-code);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  color: var(--text-primary);
}

[data-theme="dark"] .post-content code {
  background: var(--bg-tertiary);
}

.post-content pre {
  background: var(--bg-code-block);
  border-radius: var(--radius);
  padding: 1.25em 1.5em;
  overflow-x: auto;
  margin: 1.5em 0;
  position: relative;
  border: 1px solid var(--border);
}

[data-theme="dark"] .post-content pre {
  border-color: transparent;
}

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

/* Code copy button */
.code-copy-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  background: rgba(0,0,0,0.06);
  border: none;
  border-radius: 4px;
  cursor: pointer;
  padding: 0.3rem 0.5rem;
  color: var(--text-tertiary);
  font-size: 0.7rem;
  font-family: inherit;
  opacity: 0;
  transition: opacity var(--transition), background var(--transition), color var(--transition);
}

[data-theme="dark"] .code-copy-btn {
  background: rgba(255,255,255,0.1);
  color: #999;
}

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

.code-copy-btn:hover {
  background: rgba(0,0,0,0.12);
  color: var(--text-primary);
}

[data-theme="dark"] .code-copy-btn:hover {
  background: rgba(255,255,255,0.2);
  color: #fff;
}

.code-copy-btn.copied {
  color: #16a34a;
}

[data-theme="dark"] .code-copy-btn.copied {
  color: #4ade80;
}

/* --- Table of Contents --- */
.toc {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0 2rem;
}

.toc-title {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  margin-bottom: 0.75rem;
}

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

.toc ul ul {
  padding-left: 1.25em;
}

.toc li {
  margin-bottom: 0.3em;
}

.toc a {
  font-size: 0.85rem;
  color: var(--text-secondary);
  text-decoration: none;
}

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

/* --- Post Navigation --- */
.post-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 2rem 0 4rem;
  border-top: 1px solid var(--border);
}

.post-nav-item {
  padding: 1rem;
  border-radius: var(--radius);
  background: var(--bg-secondary);
  transition: background-color var(--transition);
}

.post-nav-item:hover {
  background: var(--bg-tertiary);
}

.post-nav-label {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  margin-bottom: 0.3rem;
}

.post-nav-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.4;
}

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

@media (max-width: 640px) {
  .post-nav {
    grid-template-columns: 1fr;
  }
}

/* --- All Posts Explorer (/categories) --- */
.all-posts-section {
  padding: 5rem 0 4rem;
  max-width: var(--content-width);
  margin: 0 auto;
}

.all-posts-header h1 {
  font-size: 2rem;
  margin-top: 0;
  margin-bottom: 0.45rem;
}

.all-posts-desc {
  color: var(--text-secondary);
  margin-bottom: 1.3rem;
}

.category-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-bottom: 1rem;
}

.category-filter {
  border: 1px solid var(--border);
  background: var(--bg-secondary);
  color: var(--text-secondary);
  border-radius: 999px;
  padding: 0.3rem 0.7rem;
  font-size: 0.76rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
}

.category-filter span {
  margin-left: 0.3rem;
  color: var(--text-tertiary);
}

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

.category-filter.active {
  border-color: var(--accent);
  background: var(--accent-light);
  color: var(--accent);
}

.category-filter.active span {
  color: var(--accent);
}

.all-posts-results {
  font-size: 0.8rem;
  color: var(--text-tertiary);
  margin-bottom: 0.4rem;
}

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

.all-post-item {
  padding: 1.4rem 0;
  border-bottom: 1px solid var(--border-light);
}

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

.all-post-title {
  font-size: 1.16rem;
  margin: 0 0 0.4rem;
  line-height: 1.4;
}

.all-post-title a {
  color: var(--text-primary);
}

.all-post-title a:hover {
  color: var(--accent);
}

.all-post-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 0.6rem;
}

.all-post-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.7rem;
  font-size: 0.8rem;
  color: var(--text-tertiary);
}

.all-post-meta .dot {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--text-tertiary);
}

.all-post-tags {
  display: flex;
  gap: 0.35rem;
}

.all-post-tags a {
  font-size: 0.72rem;
  font-weight: 500;
  padding: 0.15rem 0.5rem;
  background: var(--tag-bg);
  color: var(--tag-text);
  border-radius: 100px;
}

.all-post-pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.8rem;
  padding: 1.75rem 0 0.6rem;
}

.all-post-page-btn {
  border: 1px solid var(--border);
  background: var(--bg-secondary);
  color: var(--text-secondary);
  border-radius: 6px;
  padding: 0.35rem 0.9rem;
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
}

.all-post-page-btn:hover:not(:disabled) {
  border-color: var(--accent);
  color: var(--text-primary);
}

.all-post-page-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* --- Archive Page --- */
.archive-section {
  padding: 5rem 0 4rem;
  max-width: var(--content-width);
  margin: 0 auto;
}

.archive-section h1 {
  font-size: 2rem;
  margin-top: 0;
  margin-bottom: 0.5rem;
}

.archive-desc {
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

/* --- Footer --- */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  margin-top: 2rem;
}

.footer-inner {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-copy {
  font-size: 0.8rem;
  color: var(--text-tertiary);
}

.footer-links {
  display: flex;
  gap: 1rem;
}

.footer-links a {
  color: var(--text-tertiary);
  transition: color var(--transition);
}

.footer-links a:hover {
  color: var(--accent);
}

.footer-links svg {
  width: 18px;
  height: 18px;
}

@media (max-width: 640px) {
  .footer-inner {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }
}

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

/* --- MathJax Overrides --- */
.MathJax {
  font-size: 1em !important;
}

.MathJax_Display {
  overflow-x: auto;
  overflow-y: hidden;
}

/* --- Responsive embed (for YouTube etc) --- */
.embed-responsive {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  margin: 1.5em 0;
  border-radius: var(--radius);
}

.embed-responsive iframe,
.embed-responsive-item {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

/* Bootstrap grid compatibility for existing post content */
.row {
  display: flex;
  flex-wrap: wrap;
  margin-left: -0.75rem;
  margin-right: -0.75rem;
}

.col, .col-md-2, .col-md-4, .col-md-6, .col-md-8, .col-md-9, .col-md-10, .col-xs-12 {
  padding-left: 0.75rem;
  padding-right: 0.75rem;
  width: 100%;
}

@media (min-width: 768px) {
  .col-md-2 { flex: 0 0 16.667%; max-width: 16.667%; }
  .col-md-4 { flex: 0 0 33.333%; max-width: 33.333%; }
  .col-md-6 { flex: 0 0 50%; max-width: 50%; }
  .col-md-8 { flex: 0 0 66.667%; max-width: 66.667%; }
  .col-md-9 { flex: 0 0 75%; max-width: 75%; }
  .col-md-10 { flex: 0 0 83.333%; max-width: 83.333%; }
}

.text-center { text-align: center; }
.img-fluid { max-width: 100%; height: auto; }
.embed-responsive-16by9 { padding-bottom: 56.25%; }

/* Image in post content */
.post-content center {
  display: block;
  margin: 1.5em 0;
}

/* --- Syntax Highlighting (theme-aware) --- */
.highlight {
  background: var(--bg-code-block);
  border-radius: var(--radius);
  margin: 1.5em 0;
  overflow: hidden;
}

.highlight pre {
  margin: 0;
  border: none;
  color: var(--text-code);
}

.highlight .c,
.highlight .cm,
.highlight .c1,
.highlight .cs { color: var(--syntax-comment); font-style: italic; }
.highlight .k,
.highlight .kd,
.highlight .kn,
.highlight .kp,
.highlight .kr,
.highlight .kt { color: var(--syntax-keyword); }
.highlight .s,
.highlight .sb,
.highlight .sc,
.highlight .sd,
.highlight .s2,
.highlight .se,
.highlight .sh,
.highlight .si,
.highlight .sx,
.highlight .s1 { color: var(--syntax-string); }
.highlight .na { color: var(--syntax-fn); }
.highlight .nb { color: var(--syntax-builtin); }
.highlight .nc { color: var(--syntax-builtin); }
.highlight .no { color: var(--syntax-number); }
.highlight .nd { color: var(--syntax-fn); }
.highlight .nf,
.highlight .fm { color: var(--syntax-fn); }
.highlight .ni { color: var(--syntax-text); }
.highlight .nn { color: var(--syntax-text); }
.highlight .nt { color: var(--syntax-keyword); }
.highlight .nv { color: var(--syntax-number); }
.highlight .o,
.highlight .ow { color: var(--syntax-keyword); }
.highlight .p { color: var(--syntax-text); }
.highlight .mi,
.highlight .mf,
.highlight .mh,
.highlight .mo,
.highlight .il { color: var(--syntax-number); }
.highlight .gd { color: var(--syntax-deleted); }
.highlight .gi { color: var(--syntax-added); }
.highlight .err { color: var(--syntax-text); }

/* Line numbers */
.highlight .lineno {
  color: var(--syntax-lineno);
  padding-right: 1em;
  user-select: none;
  -webkit-user-select: none;
}

/* --- 404 Page --- */
.page-404 {
  text-align: center;
  padding: 8rem 0;
}

.page-404 h1 {
  font-size: 4rem;
  margin-top: 0;
}

/* --- Print Styles --- */
@media print {
  .site-nav,
  .site-footer,
  .theme-toggle,
  .code-copy-btn,
  .post-nav {
    display: none !important;
  }

  body {
    color: #000;
    background: #fff;
  }
}