/* =============================================
   TechFlow Theme — Main Stylesheet
   ============================================= */

/* ----- Custom Properties ----- */
:root {
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;

  --transition: 0.2s ease;
  --max-width: 1100px;
  --content-width: 720px;
}

/* ----- Dark Theme (default) ----- */
[data-theme="dark"] {
  --bg-base:      #0d1117;
  --bg-surface:   #161b22;
  --bg-elevated:  #21262d;
  --bg-hover:     #30363d;

  --border:       #30363d;
  --border-muted: #21262d;

  --text-primary:   #e6edf3;
  --text-secondary: #8b949e;
  --text-muted:     #6e7681;
  --text-link:      #58a6ff;
  --text-link-hover:#79c0ff;

  --accent:         #238636;
  --accent-hover:   #2ea043;
  --accent-text:    #3fb950;

  --tag-bg:         #162032;
  --tag-text:       #58a6ff;
  --tag-border:     #1f3a5f;

  --code-bg:        #161b22;
  --code-border:    #30363d;
  --code-text:      #e6edf3;

  --hero-gradient: linear-gradient(135deg, #0d1117 0%, #161b22 50%, #0d1117 100%);
  --card-shadow:   0 1px 3px rgba(0,0,0,0.4), 0 1px 2px rgba(0,0,0,0.3);
  --card-shadow-hover: 0 4px 12px rgba(0,0,0,0.5);
}

/* ----- Light Theme ----- */
[data-theme="light"] {
  --bg-base:      #ffffff;
  --bg-surface:   #f6f8fa;
  --bg-elevated:  #eaeef2;
  --bg-hover:     #e1e8f0;

  --border:       #d0d7de;
  --border-muted: #eaeef2;

  --text-primary:   #1f2328;
  --text-secondary: #656d76;
  --text-muted:     #818b95;
  --text-link:      #0969da;
  --text-link-hover:#0550ae;

  --accent:         #1a7f37;
  --accent-hover:   #1f8f40;
  --accent-text:    #1a7f37;

  --tag-bg:         #ddf4ff;
  --tag-text:       #0969da;
  --tag-border:     #b6e3ff;

  --code-bg:        #f6f8fa;
  --code-border:    #d0d7de;
  --code-text:      #1f2328;

  --hero-gradient: linear-gradient(135deg, #f6f8fa 0%, #ffffff 50%, #f0f3f6 100%);
  --card-shadow:   0 1px 3px rgba(31,35,40,0.08), 0 1px 2px rgba(31,35,40,0.06);
  --card-shadow-hover: 0 4px 12px rgba(31,35,40,0.12);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

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

#main-content {
  flex: 1;
}

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

a:hover {
  color: var(--text-link-hover);
}

img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
}

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

/* ----- Navigation ----- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--bg-base);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  background-color: color-mix(in srgb, var(--bg-base) 90%, transparent);
}

.nav {
  display: flex;
  align-items: center;
  height: 60px;
  gap: 1.5rem;
}

.nav-brand {
  flex-shrink: 0;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.02em;
}

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

.brand-icon {
  color: var(--accent-text);
  display: flex;
}

.brand-name {
  font-family: var(--font-mono);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  flex: 1;
}

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

.nav-link:hover,
.nav-link.active {
  color: var(--text-primary);
  background-color: var(--bg-elevated);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  cursor: pointer;
  padding: 0.4rem;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: color var(--transition), border-color var(--transition), background-color var(--transition);
  width: 36px;
  height: 36px;
}

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

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

.nav-hamburger {
  display: none;
  background: none;
  border: 1px solid var(--border);
  cursor: pointer;
  padding: 0.4rem 0.5rem;
  border-radius: var(--radius-sm);
  flex-direction: column;
  gap: 4px;
  width: 36px;
  height: 36px;
  justify-content: center;
  align-items: center;
}

.nav-hamburger span {
  display: block;
  width: 16px;
  height: 2px;
  background-color: var(--text-secondary);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

/* ----- Hero ----- */
.hero {
  padding: 4rem 1.5rem 3rem;
  background: var(--hero-gradient);
  border-bottom: 1px solid var(--border);
}

.hero-content {
  max-width: var(--content-width);
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3rem);
  font-family: var(--font-mono);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.03em;
  margin-bottom: 1rem;
}

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

.hero-description {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 520px;
}

/* ----- Section Header ----- */
.posts-section {
  padding: 3rem 1.5rem;
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border);
}

.section-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.8rem;
}

.section-link {
  font-size: 0.875rem;
  color: var(--text-link);
}

/* ----- Post Cards (horizontal list) ----- */
.post-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  max-width: 860px;
}

.post-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--card-shadow);
  overflow: hidden;
  display: flex;
  flex-direction: row;
  transition: box-shadow var(--transition), border-color var(--transition);
}

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

/* Featured image — fixed width column on the left */
.post-card-image-link {
  display: block;
  flex-shrink: 0;
  width: 240px;
}

.post-card-image {
  width: 240px;
  height: 100%;
  min-height: 148px;
  overflow: hidden;
  border-right: 1px solid var(--border);
  background-color: var(--bg-elevated);
}

.post-card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 0;
  transition: transform 0.35s ease;
}

.post-card:hover .post-card-image img {
  transform: scale(1.04);
}

/* Placeholder when no cover image */
.post-card-image-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  background: repeating-linear-gradient(
    -45deg,
    var(--bg-elevated),
    var(--bg-elevated) 10px,
    var(--bg-surface) 10px,
    var(--bg-surface) 20px
  );
}

.placeholder-terminal {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  background-color: var(--bg-base);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 0.5rem 0.75rem;
  width: 100%;
}

.ph-prompt {
  color: var(--accent-text);
  font-weight: 700;
}

.ph-cmd {
  color: var(--text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Card text body — fills remaining space */
.post-card-body {
  padding: 1rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  flex: 1;
  min-width: 0;
}

.post-card-title {
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.35;
  letter-spacing: -0.02em;
}

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

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

.post-card-summary {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.55;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ----- Tags ----- */
.post-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.tag {
  font-size: 0.75rem;
  font-weight: 500;
  font-family: var(--font-mono);
  padding: 0.2rem 0.6rem;
  border-radius: 20px;
  background-color: var(--tag-bg);
  color: var(--tag-text);
  border: 1px solid var(--tag-border);
  transition: background-color var(--transition);
}

.tag:hover {
  background-color: var(--bg-elevated);
  color: var(--text-link-hover);
}

/* ----- Post Meta ----- */
.post-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

.post-meta svg {
  vertical-align: -2px;
}

.post-date,
.post-reading-time,
.post-word-count,
.post-updated {
  display: flex;
  align-items: center;
  gap: 0.3rem;
}

/* ----- Page Header (list pages) ----- */
.page-header {
  padding: 2.5rem 0 2rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 2rem;
}

.page-title {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
}

.page-description {
  color: var(--text-secondary);
}

/* ----- Reading Progress Bar ----- */
.read-progress-bar {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-text), var(--text-link));
  z-index: 200;
  transition: width 0.1s linear;
  border-radius: 0 2px 2px 0;
}

/* ----- Single Post ----- */
.single-layout {
  padding: 2rem 1.5rem 4rem;
  display: grid;
  grid-template-columns: minmax(0, var(--content-width)) 220px;
  gap: 2.5rem;
  align-items: start;
  max-width: calc(var(--content-width) + 220px + 2.5rem + 3rem);
}

.post-single {
  min-width: 0;
}

.post-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}

/* Cover image on single post */
.post-cover {
  margin-bottom: 2.5rem;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
}

.post-cover img {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 7;
  object-fit: cover;
  border-radius: 0;
  display: block;
}

.post-title {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.25;
  margin: 0.75rem 0;
}

.post-description {
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.post-series {
  margin-top: 0.75rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.series-label {
  font-weight: 600;
}

.post-content-wrap {
  position: relative;
}

/* ----- TOC Sidebar ----- */
.toc-sidebar {
  position: sticky;
  top: 76px;
  background-color: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1rem;
  font-size: 0.8rem;
  max-height: calc(100vh - 96px);
  overflow-y: auto;
}

.toc-header {
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-size: 0.72rem;
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

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

.toc-nav li {
  margin: 0.25rem 0;
}

.toc-nav li li {
  padding-left: 0.75rem;
}

.toc-nav a {
  color: var(--text-secondary);
  font-size: 0.8rem;
  line-height: 1.5;
  display: block;
  padding: 0.1rem 0;
  border-left: 2px solid transparent;
  padding-left: 0.5rem;
  transition: color var(--transition), border-color var(--transition);
}

.toc-nav a:hover,
.toc-nav a.active {
  color: var(--text-link);
  border-left-color: var(--text-link);
}

/* ----- Post Content Typography ----- */
.post-content {
  font-size: 1.0rem;
  line-height: 1.8;
  overflow-wrap: break-word;
}

.post-content > * + * {
  margin-top: 1.25em;
}

.post-content h2,
.post-content h3,
.post-content h4 {
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.3;
  margin-top: 2em;
  margin-bottom: 0.5em;
  scroll-margin-top: 80px;
}

.post-content h2 {
  font-size: 1.5rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border);
}

.post-content h3 { font-size: 1.2rem; }
.post-content h4 { font-size: 1.05rem; }

.post-content h2::before {
  content: "## ";
  color: var(--accent-text);
  font-family: var(--font-mono);
  font-size: 0.9em;
  opacity: 0.7;
}

.post-content h3::before {
  content: "### ";
  color: var(--accent-text);
  font-family: var(--font-mono);
  font-size: 0.85em;
  opacity: 0.7;
}

.post-content p { margin-bottom: 1em; }

.post-content strong { font-weight: 600; color: var(--text-primary); }
.post-content em { font-style: italic; }

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

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

/* ----- Inline Code ----- */
.post-content :not(pre) > code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background-color: var(--bg-elevated);
  border: 1px solid var(--border);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
  color: var(--accent-text);
}

/* ----- Code Blocks ----- */
.post-content pre {
  position: relative;
  background-color: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.25rem;
  overflow-x: auto;
  margin: 1.5em 0;
  font-size: 0.875rem;
  line-height: 1.6;
}

.post-content pre code {
  font-family: var(--font-mono);
  background: none;
  border: none;
  padding: 0;
  color: var(--code-text);
  font-size: inherit;
}

/* Copy button */
.code-copy-btn {
  position: absolute;
  top: 0.6rem;
  right: 0.6rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  color: var(--text-muted);
  border-radius: var(--radius-sm);
  padding: 0.25rem 0.5rem;
  font-size: 0.72rem;
  font-family: var(--font-mono);
  cursor: pointer;
  opacity: 0;
  transition: opacity var(--transition), color var(--transition), background-color var(--transition);
}

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

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

.code-copy-btn.copied {
  color: var(--accent-text);
  border-color: var(--accent-text);
}

/* Lang label */
.code-lang-label {
  position: absolute;
  top: 0;
  left: 0;
  background: var(--bg-elevated);
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 0.2rem 0.6rem;
  border-bottom-right-radius: var(--radius-sm);
  border-top-left-radius: var(--radius-md);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-right: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

/* ----- Tables ----- */
.post-content table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  margin: 1.5em 0;
  overflow: hidden;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
}

.post-content th {
  background-color: var(--bg-elevated);
  font-weight: 600;
  text-align: left;
  padding: 0.6rem 1rem;
  border-bottom: 1px solid var(--border);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
}

.post-content td {
  padding: 0.6rem 1rem;
  border-bottom: 1px solid var(--border-muted);
}

.post-content tr:last-child td {
  border-bottom: none;
}

.post-content tr:hover td {
  background-color: var(--bg-surface);
}

/* ----- Blockquote ----- */
.post-content blockquote {
  border-left: 3px solid var(--accent-text);
  padding: 0.75rem 1.25rem;
  margin: 1.5em 0;
  background-color: var(--bg-surface);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  color: var(--text-secondary);
  font-style: italic;
}

.post-content blockquote p {
  margin: 0;
}

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

.post-content li {
  margin: 0.3em 0;
}

.post-content ul li::marker {
  color: var(--accent-text);
}

/* ----- Horizontal Rule ----- */
.post-content hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2.5em 0;
}

/* ----- Callout / Admonition ----- */
.post-content .callout {
  border-left: 4px solid var(--accent-text);
  background-color: var(--bg-surface);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 1rem 1.25rem;
  margin: 1.5em 0;
}

/* ----- Post Footer ----- */
.post-footer {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.post-tags-footer {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.tags-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.post-alt-formats {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
  padding-top: 1rem;
  margin-top: 0.25rem;
  border-top: 1px solid var(--border);
}

.alt-formats-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.alt-format-link {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.8rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.2rem 0.6rem;
  transition: color var(--transition), border-color var(--transition);
}

.alt-format-link:hover {
  color: var(--text-link);
  border-color: var(--text-link);
}

.post-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.post-nav-item {
  background-color: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  transition: border-color var(--transition);
}

.post-nav-item:hover {
  border-color: var(--text-link);
}

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

.post-nav-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.post-nav-item a {
  color: var(--text-primary);
  font-size: 0.9rem;
  font-weight: 500;
}

.post-nav-item a:hover {
  color: var(--text-link);
}

/* ----- Footer ----- */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.5rem 0;
  margin-top: auto;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer-left {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.footer-sep { opacity: 0.4; }

.footer-right {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.footer-right a {
  color: var(--text-muted);
  display: flex;
  transition: color var(--transition);
}

.footer-right a:hover {
  color: var(--text-primary);
}

/* ----- Pagination ----- */
.pagination {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  max-width: 780px;
}

.page-btn {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-link);
  padding: 0.45rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background-color: var(--bg-surface);
  transition: all var(--transition);
  white-space: nowrap;
}

a.page-btn:hover {
  background-color: var(--bg-elevated);
  border-color: var(--text-link);
  color: var(--text-link-hover);
}

.page-btn-disabled {
  opacity: 0.35;
  cursor: default;
  color: var(--text-muted);
}

.page-numbers {
  display: flex;
  align-items: center;
  gap: 0.3rem;
}

.page-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2rem;
  height: 2rem;
  font-size: 0.875rem;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  border: 1px solid transparent;
  transition: all var(--transition);
}

a.page-num:hover {
  background-color: var(--bg-elevated);
  border-color: var(--border);
  color: var(--text-primary);
}

.page-num-active {
  background-color: var(--bg-elevated);
  border-color: var(--text-link);
  color: var(--text-primary);
  font-weight: 600;
}

.page-ellipsis {
  color: var(--text-muted);
  padding: 0 0.2rem;
  font-size: 0.875rem;
}

/* ----- Error Page ----- */
.error-page {
  padding: 5rem 1.5rem;
  text-align: center;
}

.error-content {
  max-width: 420px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
}

.error-code {
  font-family: var(--font-mono);
  font-size: 1rem;
  background-color: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1.5rem 2rem;
  text-align: left;
  color: var(--text-secondary);
  line-height: 1.8;
  white-space: pre-wrap;
}

.err-num {
  color: #f85149;
  font-weight: 700;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  padding: 0.6rem 1.25rem;
  background-color: var(--accent);
  color: #fff;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.9rem;
  transition: background-color var(--transition);
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  color: #fff;
}

/* ----- Taxonomy Pages ----- */
.terms-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  padding: 2rem 0;
}

.term-item a {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0.9rem;
  background-color: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  font-size: 0.875rem;
  color: var(--text-secondary);
  transition: all var(--transition);
}

.term-item a:hover {
  border-color: var(--text-link);
  color: var(--text-link);
}

.term-count {
  font-size: 0.75rem;
  background-color: var(--bg-elevated);
  padding: 0.1rem 0.4rem;
  border-radius: 10px;
  color: var(--text-muted);
}

/* ----- Responsive ----- */
@media (max-width: 1000px) {
  .single-layout {
    grid-template-columns: 1fr;
  }

  .toc-sidebar {
    display: none;
  }
}

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

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

  /* Cards go back to vertical on medium screens */
  .post-card {
    flex-direction: column;
  }

  .post-card-image-link {
    width: 100%;
  }

  .post-card-image {
    width: 100%;
    height: 160px;
    min-height: unset;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }

  .post-card-summary {
    -webkit-line-clamp: 3;
  }
}

@media (max-width: 640px) {
  .nav-menu {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background-color: var(--bg-surface);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 0.75rem 1rem;
    gap: 0;
  }

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

  .nav-link {
    padding: 0.6rem 0.75rem;
    width: 100%;
  }

  .nav-hamburger {
    display: flex;
  }

  .post-card-body {
    padding: 1.25rem 1.25rem 1.5rem;
  }

  .footer-inner {
    flex-direction: column;
    gap: 0.75rem;
    text-align: center;
  }

  .hero {
    padding: 2.5rem 1.5rem 2rem;
  }

  .single-layout {
    padding: 1.5rem 1.5rem 3rem;
  }
}

/* ----- Nav search button ----- */
.nav-search-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  color: var(--text-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: color var(--transition), background-color var(--transition), border-color var(--transition);
  flex-shrink: 0;
}

.nav-search-btn:hover,
.nav-search-btn.active {
  color: var(--text-primary);
  background-color: var(--bg-elevated);
}

/* ----- Search page ----- */
.search-page {
  padding: 3rem 1.5rem 5rem;
  max-width: 760px;
  margin: 0 auto;
}

.search-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
}

.search-input-wrap {
  position: relative;
  display: flex;
  align-items: center;
}

.search-input-icon {
  position: absolute;
  left: 0.875rem;
  color: var(--text-muted);
  display: flex;
  pointer-events: none;
}

.search-input {
  width: 100%;
  padding: 0.75rem 2.75rem;
  font-size: 1rem;
  font-family: var(--font-sans);
  background-color: var(--bg-surface);
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.search-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.15);
}

.search-input::placeholder {
  color: var(--text-muted);
}

.search-clear {
  position: absolute;
  right: 0.75rem;
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  padding: 0.25rem;
  border-radius: var(--radius-sm);
  transition: color var(--transition);
}

.search-clear:hover {
  color: var(--text-primary);
}

.search-count {
  margin-top: 0.75rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  min-height: 1.25rem;
}

.search-results {
  margin-top: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0;
}

.search-result {
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--border);
}

.search-result:first-child {
  border-top: 1px solid var(--border);
}

.search-result-meta {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 0.4rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.search-result-tags {
  display: flex;
  gap: 0.35rem;
  flex-wrap: wrap;
}

.search-result-tag {
  background-color: var(--bg-elevated);
  color: var(--accent-text);
  padding: 0.1rem 0.45rem;
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-family: var(--font-mono);
  transition: background-color var(--transition);
}

.search-result-tag:hover {
  background-color: var(--border);
  color: var(--text-primary);
}

.search-result-title {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 0.35rem;
  line-height: 1.4;
}

.search-result-title a {
  color: var(--text-primary);
  transition: color var(--transition);
}

.search-result-title a:hover {
  color: var(--accent-text);
}

.search-result-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.search-empty {
  padding: 2rem 0;
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* ----- Scrollbar ----- */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg-base); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* ----- Selection ----- */
::selection {
  background-color: rgba(88, 166, 255, 0.2);
  color: var(--text-primary);
}