/* ==========================================================================
   Monolog - Modern Developer Blog Skin for Tistory
   Version: 1.0.0
   Author: Monolog
   Description: Clean, minimal developer blog with dark mode, code highlighting,
                PlantUML support, and responsive layout.
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. CSS Custom Properties
   -------------------------------------------------------------------------- */

:root {
  /* Background */
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;

  /* Text */
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-tertiary: #94a3b8;

  /* Borders */
  --border-color: #e2e8f0;
  --border-hover: #cbd5e1;

  /* Accent */
  --accent: #6366f1;
  --accent-hover: #4f46e5;
  --accent-light: #eef2ff;
  --color-success: #22c55e;

  /* Code */
  --code-bg: #f8fafc;
  --code-border: #e2e8f0;

  /* Shadows */
  --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 15px rgba(0, 0, 0, 0.1);

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

  /* Layout */
  --header-height: 64px;
  --sidebar-width: 280px;
  --content-max-width: 720px;
  --container-max-width: 1200px;

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-base: 0.2s ease;
  --transition-slow: 0.3s ease;
}

html.dark {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;

  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-tertiary: #64748b;

  --border-color: #334155;
  --border-hover: #475569;

  --accent: #818cf8;
  --accent-hover: #6366f1;
  --accent-light: #1e1b4b;
  --color-success: #4ade80;

  --code-bg: #1e293b;
  --code-border: #334155;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.5);
}


/* --------------------------------------------------------------------------
   2. Reset & Base
   -------------------------------------------------------------------------- */

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: "Pretendard Variable", Pretendard, -apple-system,
    BlinkMacSystemFont, system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--transition-slow),
    color var(--transition-slow);
  word-break: keep-all;
  overflow-wrap: break-word;
}

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

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

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

ul,
ol {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

input,
textarea {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
}

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

body.no-scroll {
  overflow: hidden;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}


/* --------------------------------------------------------------------------
   3. Typography
   -------------------------------------------------------------------------- */

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

h1 { font-size: 2.25rem; }
h2 { font-size: 1.75rem; }
h3 { font-size: 1.375rem; }
h4 { font-size: 1.125rem; }
h5 { font-size: 1rem; }
h6 { font-size: 0.875rem; }

p {
  margin-bottom: 1.5rem;
  color: var(--text-primary);
}

code {
  font-family: "JetBrains Mono", "Fira Code", "Source Code Pro", monospace;
  font-size: 0.875em;
  background-color: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: 4px;
  padding: 0.15em 0.4em;
  word-break: break-word;
}

blockquote {
  border-left: 4px solid var(--accent);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  background-color: var(--bg-secondary);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-secondary);
  font-style: italic;
}

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


/* --------------------------------------------------------------------------
   4. Header
   -------------------------------------------------------------------------- */

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  z-index: 100;
  transition: background-color var(--transition-slow),
    border-color var(--transition-slow);
}

.header-inner {
  max-width: var(--container-max-width);
  height: 100%;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.header-brand {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  flex-shrink: 0;
}

.header-logo a {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.02em;
  white-space: nowrap;
}

.header-logo a:hover {
  color: var(--accent);
  text-decoration: none;
}

.blog-subtitle {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  white-space: nowrap;
}

.header-with-cover {
  border-bottom: none;
}

.header-with-cover .header-logo a,
.header-with-cover .header-nav a,
.header-with-cover .btn-icon {
  color: #ffffff;
}

.header-with-cover .blog-subtitle {
  color: rgba(255, 255, 255, 0.7);
}

.header-with-cover .btn-icon:hover {
  background-color: rgba(255, 255, 255, 0.15);
  color: #ffffff;
}

.header-nav {
  margin-left: auto;
  display: flex;
  align-items: center;
}

.header-nav ul {
  display: flex;
  align-items: center;
  gap: 1.75rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.header-nav a {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  padding: 0.25rem 0;
  position: relative;
  transition: color var(--transition-base);
}

.header-nav a::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--accent);
  transform: scaleX(0);
  transform-origin: center;
  transition: transform var(--transition-base);
}

.header-nav a:hover,
.header-nav a.active {
  color: var(--accent);
  text-decoration: none;
}

.header-nav a:hover::after,
.header-nav a.active::after {
  transform: scaleX(1);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-icon {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  transition: background-color var(--transition-base),
    color var(--transition-base);
}

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

.btn-icon svg {
  width: 20px;
  height: 20px;
}

.dark-toggle .icon-sun {
  display: block;
}

.dark-toggle .icon-moon {
  display: none;
}

html.dark .dark-toggle .icon-sun {
  display: none;
}

html.dark .dark-toggle .icon-moon {
  display: block;
}

.hamburger {
  display: none;
}

.hamburger .icon-menu {
  display: block;
}

.hamburger .icon-close {
  display: none;
}

.hamburger.active .icon-menu {
  display: none;
}

.hamburger.active .icon-close {
  display: block;
}

.mobile-menu {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  padding: 1rem 1.5rem;
  z-index: 99;
  animation: slideDown var(--transition-base) ease-out;
}

.mobile-menu.active {
  display: block;
}

.mobile-menu ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.mobile-menu li {
  border-bottom: 1px solid var(--border-color);
}

.mobile-menu li:last-child {
  border-bottom: none;
}

.mobile-menu a {
  display: block;
  padding: 0.75rem 0;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
}

.mobile-menu a:hover {
  color: var(--accent);
  text-decoration: none;
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}


/* --------------------------------------------------------------------------
   5. Container & Layout
   -------------------------------------------------------------------------- */

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

main > .container {
  padding-top: calc(var(--header-height) + 2rem);
  padding-bottom: 3rem;
}

.layout {
  display: grid;
  grid-template-columns: 1fr var(--sidebar-width);
  gap: 3rem;
  align-items: start;
}

.layout.no-sidebar {
  grid-template-columns: 1fr;
}

.content-area {
  min-width: 0;
}

.cover-section {
  text-align: center;
  padding: 3rem 0 2rem;
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--border-color);
}

.cover-section .blog-title {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
  letter-spacing: -0.03em;
}

.cover-section .blog-subtitle {
  font-size: 1.0625rem;
  color: var(--text-secondary);
  font-weight: 400;
}


/* --------------------------------------------------------------------------
   6. Post List - List View
   -------------------------------------------------------------------------- */

.post-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.post-card {
  display: flex;
  flex-direction: row;
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  cursor: pointer;
  transition: box-shadow var(--transition-base),
    border-color var(--transition-base),
    transform var(--transition-base);
}

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

.post-card .post-thumbnail {
  width: 200px;
  min-height: 160px;
  flex-shrink: 0;
  overflow: hidden;
}

.post-card .post-thumbnail img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-slow);
}

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

.post-card .post-info {
  display: flex;
  flex-direction: column;
  padding: 1.5rem;
  flex: 1;
  min-width: 0;
}

.post-card .post-category {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: #ffffff;
  background-color: var(--accent);
  padding: 0.2em 0.6em;
  border-radius: 4px;
  margin-bottom: 0.625rem;
  width: fit-content;
  text-decoration: none;
  transition: background-color var(--transition-base);
}

.post-card .post-category:hover {
  background-color: var(--accent-hover);
  text-decoration: none;
}

.post-card .post-title {
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: 0.5rem;
}

.post-card .post-title a {
  color: var(--text-primary);
  text-decoration: none;
  transition: color var(--transition-base);
}

.post-card .post-title a:hover {
  color: var(--accent);
  text-decoration: none;
}

.post-card .post-date {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  margin-bottom: 0.75rem;
}

.post-card .post-summary {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-top: auto;
  margin-bottom: 0;
}


/* --------------------------------------------------------------------------
   7. Post List - Grid View
   -------------------------------------------------------------------------- */

.post-list.grid-view {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.post-list.grid-view .post-card {
  flex-direction: column;
}

.post-list.grid-view .post-card .post-thumbnail {
  width: 100%;
  min-height: 0;
  aspect-ratio: 16 / 9;
}

.post-list.grid-view .post-card .post-info {
  padding: 1.25rem;
}

.post-list.grid-view .post-card .post-title {
  font-size: 1.125rem;
}

.post-list.grid-view .post-card .post-summary {
  -webkit-line-clamp: 2;
}

.post-card.notice {
  border-left: 3px solid var(--accent);
}

.notice-badge {
  display: inline-block;
  font-size: 0.6875rem;
  font-weight: 600;
  color: var(--accent);
  background-color: var(--accent-light);
  padding: 0.125rem 0.5rem;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}


/* --------------------------------------------------------------------------
   8. Single Post
   -------------------------------------------------------------------------- */

.post-header {
  text-align: center;
  padding-bottom: 2rem;
  margin-bottom: 2.5rem;
  border-bottom: 1px solid var(--border-color);
}

.post-header .post-category {
  display: inline-block;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 0.75rem;
  text-decoration: none;
}

.post-header .post-category:hover {
  color: var(--accent-hover);
  text-decoration: underline;
}

.post-header .post-title {
  font-size: 2rem;
  font-weight: 800;
  line-height: 1.3;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}

.post-header .post-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  font-size: 0.875rem;
  color: var(--text-tertiary);
}

.post-header .post-meta span::before {
  content: "\00b7";
  margin-right: 1rem;
}

.post-header .post-meta span:first-child::before {
  display: none;
}

.post-admin {
  display: flex;
  gap: 0.5rem;
  margin-top: 1rem;
  justify-content: center;
}

.post-admin a {
  font-size: 0.8125rem;
  padding: 0.375rem 0.875rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  text-decoration: none;
  transition: all var(--transition-base);
}

.post-admin a:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* Post Content */

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

.post-content p {
  margin-bottom: 1.5rem;
  line-height: 1.8;
  color: var(--text-primary);
}

.post-content h2 {
  font-size: 1.75rem;
  margin-top: 3rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-color);
  letter-spacing: -0.01em;
}

.post-content h3 {
  font-size: 1.375rem;
  margin-top: 2.5rem;
  margin-bottom: 0.75rem;
}

.post-content h4 {
  font-size: 1.125rem;
  margin-top: 2rem;
  margin-bottom: 0.5rem;
}

.post-content ul,
.post-content ol {
  padding-left: 1.5rem;
  margin-bottom: 1.5rem;
  list-style: initial;
}

.post-content ol {
  list-style: decimal;
}

.post-content li {
  margin-bottom: 0.4rem;
  line-height: 1.8;
  color: var(--text-primary);
}

.post-content li > ul,
.post-content li > ol {
  margin-top: 0.4rem;
  margin-bottom: 0;
}

.post-content img {
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  margin: 2rem auto;
}

.post-content a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition-base),
    color var(--transition-base);
}

.post-content a:hover {
  color: var(--accent-hover);
  border-bottom-color: var(--accent-hover);
  text-decoration: none;
}

.table-wrap {
  overflow-x: auto;
  margin: 1.5rem 0;
  -webkit-overflow-scrolling: touch;
}

.table-wrap table {
  margin: 0;
}

.post-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.9375rem;
}

.post-content thead th {
  background-color: var(--bg-secondary);
  font-weight: 600;
  text-align: left;
  padding: 0.75rem 1rem;
  border-bottom: 2px solid var(--border-color);
  white-space: nowrap;
}

.post-content tbody td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-color);
}

.post-content tbody tr:nth-child(even) {
  background-color: var(--bg-secondary);
}

.post-content hr {
  border: none;
  border-top: 1px solid var(--border-color);
  margin: 2.5rem 0;
}

.post-content blockquote {
  position: relative;
  border: none;
  padding: 2.5rem 2rem 1.5rem;
  margin: 2rem 0;
  background-color: transparent;
  text-align: center;
  color: var(--text-secondary);
  font-style: normal;
  font-size: 1.0625rem;
  line-height: 1.8;
}

.post-content blockquote::before {
  content: "\201C";
  display: block;
  font-size: 3rem;
  line-height: 1;
  color: var(--accent);
  opacity: 0.5;
  margin-bottom: 0.5rem;
  font-family: Georgia, "Times New Roman", serif;
}

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

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


/* --------------------------------------------------------------------------
   Protected Post
   -------------------------------------------------------------------------- */

.protected-post {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 4rem 2rem;
  text-align: center;
}

.protected-post svg {
  color: var(--text-tertiary);
  margin-bottom: 1.5rem;
}

.protected-post h2 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

.protected-post p {
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

.protected-post form {
  display: flex;
  gap: 0.5rem;
  max-width: 360px;
  width: 100%;
}

.protected-post input[type="password"] {
  flex: 1;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-size: 0.9375rem;
  outline: none;
  transition: border-color var(--transition-base);
}

.protected-post input[type="password"]:focus {
  border-color: var(--accent);
}

.protected-post button[type="submit"] {
  padding: 0.75rem 1.5rem;
  background-color: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius-md);
  font-weight: 500;
  cursor: pointer;
  transition: background-color var(--transition-base);
}

.protected-post button[type="submit"]:hover {
  background-color: var(--accent-hover);
}


/* --------------------------------------------------------------------------
   9. Code Blocks
   -------------------------------------------------------------------------- */

pre {
  background-color: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: var(--radius-md);
  margin: 1.5rem 0;
  overflow: hidden;
}

pre code {
  display: block;
  padding: 1.5rem;
  overflow-x: auto;
  font-family: "JetBrains Mono", "Fira Code", "Source Code Pro", monospace;
  font-size: 0.875rem;
  line-height: 1.6;
  background: none;
  border: none;
  border-radius: 0;
  word-break: normal;
}

.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.5rem 1rem;
  background-color: var(--bg-tertiary);
  border-bottom: 1px solid var(--code-border);
  font-size: 0.8125rem;
}

.code-header .code-lang {
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-size: 0.75rem;
}

.code-header .btn-copy {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  transition: color var(--transition-base),
    background-color var(--transition-base);
}

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

.code-header .btn-copy svg {
  width: 14px;
  height: 14px;
}

.copy-success {
  color: var(--color-success);
}

.copy-success svg {
  animation: checkPop var(--transition-base) ease-out;
}

@keyframes checkPop {
  0% { transform: scale(0.5); opacity: 0; }
  60% { transform: scale(1.15); }
  100% { transform: scale(1); opacity: 1; }
}

/* Custom scrollbar for code blocks */
pre code::-webkit-scrollbar {
  height: 6px;
}

pre code::-webkit-scrollbar-track {
  background: transparent;
}

pre code::-webkit-scrollbar-thumb {
  background-color: var(--border-color);
  border-radius: 3px;
}

pre code::-webkit-scrollbar-thumb:hover {
  background-color: var(--border-hover);
}


/* --------------------------------------------------------------------------
   10. Table of Contents (TOC)
   -------------------------------------------------------------------------- */

.toc {
  position: fixed;
  left: max(1rem, calc((100vw - var(--container-max-width)) / 2 - 220px));
  top: calc(var(--header-height) + 2rem);
  width: 200px;
  max-height: calc(100vh - var(--header-height) - 4rem);
  overflow-y: auto;
  padding-right: 0.5rem;
}

/* Hide TOC on smaller screens where there's no room */
@media (max-width: 1440px) {
  .toc {
    position: static;
    width: 100%;
    max-height: none;
    margin-bottom: 2rem;
    padding: 1rem;
    background-color: var(--bg-secondary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
  }
}

.toc-title {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 0.75rem;
}

.toc-list {
  list-style: none;
}

.toc-list li {
  margin-bottom: 0.125rem;
}

.toc-link {
  display: block;
  font-size: 0.875rem;
  color: var(--text-tertiary);
  text-decoration: none;
  padding: 0.3rem 0 0.3rem 0.75rem;
  border-left: 2px solid transparent;
  transition: color var(--transition-base),
    border-color var(--transition-base);
  line-height: 1.4;
}

.toc-link:hover {
  color: var(--text-secondary);
  text-decoration: none;
}

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

.toc-sublist {
  list-style: none;
  padding: 0;
  margin: 0.125rem 0 0;
}

.toc-sublist .toc-link {
  padding-left: 1.5rem;
  font-size: 0.8125rem;
}

/* TOC custom scrollbar */
.toc::-webkit-scrollbar {
  width: 3px;
}

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

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

/* Mobile TOC collapsible */
.toc-mobile-toggle {
  display: none;
  width: 100%;
  padding: 0.75rem 1rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.875rem;
  color: var(--text-secondary);
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
  transition: background-color var(--transition-base);
}

.toc-mobile-toggle:hover {
  background-color: var(--bg-tertiary);
}

.toc-mobile-toggle svg {
  width: 16px;
  height: 16px;
  transition: transform var(--transition-base);
}

.toc-mobile-toggle.open svg {
  transform: rotate(180deg);
}


/* --------------------------------------------------------------------------
   11. Tags
   -------------------------------------------------------------------------- */

.post-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 2rem 0;
}

.post-tags a,
.tag {
  display: inline-block;
  font-size: 0.8125rem;
  color: var(--text-secondary);
  background-color: var(--bg-secondary);
  padding: 0.3em 0.75em;
  border-radius: var(--radius-sm);
  text-decoration: none;
  border: 1px solid var(--border-color);
  transition: color var(--transition-base),
    background-color var(--transition-base),
    border-color var(--transition-base);
}

.post-tags a:hover,
.tag:hover {
  color: var(--accent);
  background-color: var(--accent-light);
  border-color: var(--accent);
  text-decoration: none;
}


/* --------------------------------------------------------------------------
   12. Prev/Next Navigation
   -------------------------------------------------------------------------- */

.post-navigation {
  display: flex;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.post-nav-item {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 1.25rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: box-shadow var(--transition-base),
    border-color var(--transition-base),
    transform var(--transition-base);
}

.post-nav-item:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--border-hover);
  transform: translateY(-2px);
  text-decoration: none;
}

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

.post-nav-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 0.375rem;
  display: flex;
  align-items: center;
  gap: 0.375rem;
}

.post-nav-item.next .post-nav-label {
  justify-content: flex-end;
}

.post-nav-label svg {
  width: 14px;
  height: 14px;
}

.post-nav-title {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}


/* --------------------------------------------------------------------------
   13. Comments
   -------------------------------------------------------------------------- */

/* Comment section */
.comments-section {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.comments-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
}

.comments-count {
  color: var(--accent);
}

.comment-list {
  list-style: none;
}

/* Comment item */
.comment-item {
  padding: 1.25rem 0;
  border-bottom: 1px solid var(--border-color);
}

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

/* Layout: avatar + content side by side */
.comment-inner {
  display: flex;
  gap: 0.875rem;
}

.comment-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
  background-color: var(--bg-tertiary);
}

.comment-content {
  flex: 1;
  min-width: 0;
}

/* Comment header */
.comment-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.375rem;
  flex-wrap: wrap;
}

.comment-author {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
}

.comment-author a {
  color: var(--text-primary);
  text-decoration: none;
}

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

/* Tistory profile link badge */
.comment-header .profileLink,
.comment-header a[class*="profile"] {
  display: inline-flex;
  align-items: center;
  padding: 0.0625rem 0.375rem;
  font-size: 0.6875rem;
  font-weight: 500;
  color: var(--text-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 3px;
  text-decoration: none;
  line-height: 1.4;
}

.comment-header .profileLink:hover,
.comment-header a[class*="profile"]:hover {
  color: var(--accent);
  border-color: var(--accent);
}

.comment-date {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
}

/* Tistory report link */
.comment-header .tt_txt_report,
.comment-header a[onclick*="report"] {
  font-size: 0.75rem;
  color: var(--text-tertiary);
  text-decoration: none;
  margin-left: auto;
}

.comment-header .tt_txt_report:hover,
.comment-header a[onclick*="report"]:hover {
  color: var(--accent);
}

/* Comment body */
.comment-body {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.7;
  word-break: break-word;
}

.comment-body p {
  margin-bottom: 0.5rem;
}

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

/* Comment actions */
.comment-actions {
  margin-top: 0.5rem;
  display: flex;
  gap: 0.75rem;
}

.comment-actions button,
.comment-actions a {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  text-decoration: none;
  transition: color var(--transition-base);
}

.comment-actions button:hover,
.comment-actions a:hover {
  color: var(--accent);
}

/* Nested replies (대댓글) */
.reply-list {
  margin-top: 0.25rem;
  padding-left: 3rem;
}

.reply-list .comment-item {
  border-bottom: none;
  padding: 0.75rem 0;
}

.reply-list .comment-item:first-child {
  padding-top: 1rem;
}

.reply-list .comment-avatar {
  width: 32px;
  height: 32px;
}

/* Admin comment highlight */
.rp_admin > .comment-inner .comment-author::after {
  content: "관리자";
  display: inline-block;
  margin-left: 0.375rem;
  padding: 0.0625rem 0.375rem;
  font-size: 0.6875rem;
  font-weight: 500;
  color: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 3px;
  line-height: 1.4;
}

/* Secret comment */
.rp_secret > .comment-inner .comment-author::after {
  content: "비밀";
  display: inline-block;
  margin-left: 0.375rem;
  padding: 0.0625rem 0.375rem;
  font-size: 0.6875rem;
  font-weight: 500;
  color: var(--text-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 3px;
  line-height: 1.4;
}

/* Hidden secret comment (no read permission) */
.hiddenComment .comment-body {
  color: var(--text-tertiary);
  font-style: italic;
}

/* Comment form */
.comment-form {
  margin-top: 2rem;
  padding: 1.5rem;
  background-color: var(--bg-secondary);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.comment-form .form-row {
  display: flex;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.comment-form textarea {
  width: 100%;
  min-height: 120px;
  padding: 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-size: 0.9375rem;
  resize: vertical;
  line-height: 1.6;
  transition: border-color var(--transition-base),
    box-shadow var(--transition-base);
}

.comment-form textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.comment-form input[type="text"],
.comment-form input[type="password"] {
  flex: 1;
  padding: 0.625rem 0.875rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-size: 0.875rem;
  transition: border-color var(--transition-base),
    box-shadow var(--transition-base);
}

.comment-form input[type="text"]:focus,
.comment-form input[type="password"]:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-light);
}

/* Comment form footer */
.comment-form-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 0.75rem;
}

.comment-form-footer .secret-check {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
  cursor: pointer;
  user-select: none;
}

.comment-form-footer .secret-check input[type="checkbox"] {
  accent-color: var(--accent);
}

/* Submit button (shared for comment + guestbook) */
.btn-submit {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.5rem 1.25rem;
  background-color: var(--accent);
  color: #ffffff;
  font-weight: 600;
  font-size: 0.875rem;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background-color var(--transition-base),
    transform var(--transition-fast);
}

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

.btn-submit:active {
  transform: scale(0.98);
}


/* --------------------------------------------------------------------------
   14. Sidebar
   -------------------------------------------------------------------------- */

.sidebar {
  position: sticky;
  top: calc(var(--header-height) + 2rem);
}

.sidebar-widget {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.sidebar-widget:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.sidebar-widget-title {
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 0.875rem;
}

/* Category list */
.category-list {
  list-style: none;
}

.category-list li {
  margin-bottom: 0.125rem;
}

.category-list a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.4rem 0.5rem;
  font-size: 0.9375rem;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: color var(--transition-base),
    background-color var(--transition-base);
}

.category-list a:hover {
  color: var(--accent);
  background-color: var(--accent-light);
  text-decoration: none;
}

.category-list .category-count {
  font-size: 0.75rem;
  color: var(--text-tertiary);
  background-color: var(--bg-tertiary);
  padding: 0.1em 0.5em;
  border-radius: 10px;
  min-width: 1.5rem;
  text-align: center;
}

/* Sub-categories */
.category-list .sub-category {
  padding-left: 1rem;
}

/* Recent posts widget */
.recent-posts {
  list-style: none;
}

.recent-posts li {
  margin-bottom: 0.75rem;
}

.recent-posts li:last-child {
  margin-bottom: 0;
}

.recent-posts a {
  font-size: 0.875rem;
  color: var(--text-secondary);
  text-decoration: none;
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  transition: color var(--transition-base);
}

.recent-posts a:hover {
  color: var(--accent);
  text-decoration: none;
}

.recent-posts .recent-post-date {
  display: block;
  font-size: 0.75rem;
  color: var(--text-tertiary);
  margin-top: 0.125rem;
}

/* Sidebar profile / about */
.sidebar-profile {
  text-align: center;
}

.sidebar-profile img {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  margin: 0 auto 0.75rem;
  object-fit: cover;
}

.sidebar-profile .profile-name {
  font-weight: 600;
  font-size: 1rem;
  margin-bottom: 0.25rem;
}

.sidebar-profile .profile-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.5;
}


/* --------------------------------------------------------------------------
   15. Pagination
   -------------------------------------------------------------------------- */

.pagination {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.375rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.pagination a,
.pagination span {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: color var(--transition-base),
    background-color var(--transition-base),
    border-color var(--transition-base);
}

.pagination a:hover {
  color: var(--accent);
  border-color: var(--accent);
  background-color: var(--accent-light);
  text-decoration: none;
}

.pagination .current,
.pagination .selected,
.pagination a.num:not([href]) {
  color: #ffffff;
  background-color: var(--accent);
  border-color: var(--accent);
  font-weight: 600;
  pointer-events: none;
}

.pagination .prev,
.pagination .next {
  font-size: 1rem;
}

.pagination .disabled,
.pagination .no_more_prev,
.pagination .no_more_next,
.pagination a:not([href]):not(.num) {
  color: var(--text-tertiary);
  border-color: var(--border-color);
  opacity: 0.5;
  pointer-events: none;
}


/* --------------------------------------------------------------------------
   16. Guestbook
   -------------------------------------------------------------------------- */

.guestbook-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.guestbook-entry {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  transition: border-color var(--transition-base);
}

.guestbook-entry:hover {
  border-color: var(--border-hover);
}

.guestbook-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.guestbook-author {
  font-weight: 600;
  font-size: 0.9375rem;
}

.guestbook-date {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
}

.guestbook-body {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

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

.guestbook-entry > .comment-reply {
  margin-top: 0.75rem;
  padding-top: 0.75rem;
  padding-left: 1rem;
  border-top: 1px solid var(--border-color);
  border-left: 3px solid var(--accent);
}

.guestbook-form {
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border-color);
}

.guestbook-form textarea {
  width: 100%;
  min-height: 120px;
  padding: 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 0.9375rem;
  line-height: 1.6;
  resize: vertical;
  outline: none;
  transition: border-color var(--transition-base);
}

.guestbook-form textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.guestbook-form .form-row {
  display: flex;
  gap: 0.75rem;
  margin-top: 0.75rem;
  flex-wrap: wrap;
}

.guestbook-form input[type="text"],
.guestbook-form input[type="password"],
.guestbook-form input[type="url"] {
  flex: 1;
  min-width: 120px;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-size: 0.875rem;
  outline: none;
  transition: border-color var(--transition-base);
}

.guestbook-form input[type="text"]:focus,
.guestbook-form input[type="password"]:focus,
.guestbook-form input[type="url"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.guestbook-form input[type="url"] {
  display: block;
  width: 100%;
  margin-top: 0.75rem;
}

/* .btn-submit styles now shared — see comment section */


/* --------------------------------------------------------------------------
   Footer
   -------------------------------------------------------------------------- */

.footer {
  margin-top: 4rem;
  padding: 2.5rem 0;
  border-top: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
}

.footer-inner {
  text-align: center;
}

.footer-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.footer-copyright {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  margin-bottom: 0.25rem;
}

.footer-powered {
  font-size: 0.75rem;
  color: var(--text-tertiary);
}

.footer-powered a {
  color: var(--accent);
  text-decoration: none;
}

.footer-powered a:hover {
  text-decoration: underline;
}


/* --------------------------------------------------------------------------
   17. Search Overlay
   -------------------------------------------------------------------------- */

.search-overlay {
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.6);
  z-index: 200;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 20vh;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-slow);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

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

.search-container {
  position: relative;
  width: 100%;
  max-width: 600px;
  background-color: var(--bg-primary);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  transform: translateY(-16px);
  transition: transform var(--transition-slow);
}

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

.search-input-wrap {
  display: flex;
  align-items: center;
  padding: 1rem 1.5rem;
  gap: 0.75rem;
  border-bottom: 1px solid var(--border-color);
}

.search-input-wrap svg {
  width: 22px;
  height: 22px;
  color: var(--text-tertiary);
  flex-shrink: 0;
}

.search-input-wrap input {
  flex: 1;
  border: none;
  background: transparent;
  font-size: 1.125rem;
  color: var(--text-primary);
  outline: none;
}

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

.search-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-tertiary);
  background: none;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  flex-shrink: 0;
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

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

.search-close svg {
  width: 20px;
  height: 20px;
}

.search-results {
  max-height: 400px;
  overflow-y: auto;
  padding: 0.5rem;
}

.search-result-item {
  display: block;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm);
  text-decoration: none;
  transition: background-color var(--transition-fast);
}

.search-result-item:hover {
  background-color: var(--bg-secondary);
  text-decoration: none;
}

.search-result-item .result-title {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.search-result-item .result-snippet {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  display: -webkit-box;
  -webkit-line-clamp: 1;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.search-no-result {
  padding: 2rem;
  text-align: center;
  color: var(--text-tertiary);
  font-size: 0.9375rem;
}


/* --------------------------------------------------------------------------
   18. Back to Top
   -------------------------------------------------------------------------- */

.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background-color: var(--accent);
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  opacity: 0;
  pointer-events: none;
  transform: translateY(20px);
  transition: opacity var(--transition-base),
    transform var(--transition-base),
    background-color var(--transition-base),
    box-shadow var(--transition-base);
  z-index: 50;
}

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

.back-to-top:hover {
  background-color: var(--accent-hover);
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px) scale(1.05);
}

.back-to-top svg {
  width: 22px;
  height: 22px;
}


/* --------------------------------------------------------------------------
   19. PlantUML
   -------------------------------------------------------------------------- */

.plantuml-diagram {
  text-align: center;
  margin: 2rem 0;
}

.plantuml-diagram img {
  max-width: 100%;
  height: auto;
  margin: 0 auto;
  border-radius: var(--radius-sm);
}

html.dark .plantuml-diagram img[src$=".svg"] {
  filter: invert(0.88) hue-rotate(180deg);
}

.plantuml-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  margin-top: 0.5rem;
  padding: 0.3em 0.75em;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  transition: color var(--transition-base),
    border-color var(--transition-base);
}

.plantuml-toggle:hover {
  color: var(--text-secondary);
  border-color: var(--border-hover);
}


/* --------------------------------------------------------------------------
   20. Reading Progress Bar
   -------------------------------------------------------------------------- */

.reading-progress {
  position: fixed;
  top: var(--header-height);
  left: 0;
  width: 100%;
  height: 3px;
  background-color: transparent;
  z-index: 99;
}

.reading-progress-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent), var(--accent-hover));
  transition: width 0.1s linear;
  border-radius: 0 2px 2px 0;
}


/* --------------------------------------------------------------------------
   21. Reading Time Badge
   -------------------------------------------------------------------------- */

.reading-time {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.8125rem;
  color: var(--text-tertiary);
}

.reading-time:empty {
  display: none;
}


/* --------------------------------------------------------------------------
   22. Write Button
   -------------------------------------------------------------------------- */

.btn-write {
  text-decoration: none;
  color: var(--text-secondary);
}

.btn-write:hover {
  color: var(--accent);
}


/* --------------------------------------------------------------------------
   23. Heading Anchor Links
   -------------------------------------------------------------------------- */

.heading-anchor {
  display: inline-block;
  margin-left: 0.375rem;
  color: var(--text-tertiary);
  opacity: 0;
  text-decoration: none;
  transition: opacity var(--transition-fast), color var(--transition-fast);
  vertical-align: middle;
  line-height: 1;
}

.heading-anchor svg {
  width: 0.75em;
  height: 0.75em;
  vertical-align: middle;
}

.post-content h2:hover .heading-anchor,
.post-content h3:hover .heading-anchor,
.post-content h4:hover .heading-anchor,
.heading-anchor:focus {
  opacity: 1;
}

.heading-anchor:hover {
  color: var(--accent);
}

.heading-anchor-toast {
  position: fixed;
  bottom: 5rem;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-md);
  font-size: 0.8125rem;
  box-shadow: var(--shadow-md);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base), transform var(--transition-base);
  z-index: 300;
}

.heading-anchor-toast.visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}


/* --------------------------------------------------------------------------
   24. Image Lightbox
   -------------------------------------------------------------------------- */

.lightbox {
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.9);
  z-index: 310;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-slow);
  cursor: zoom-out;
}

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

.lightbox-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  background: rgba(255, 255, 255, 0.1);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  transition: background-color var(--transition-fast);
  z-index: 1;
}

.lightbox-close:hover {
  background: rgba(255, 255, 255, 0.25);
}

.lightbox-img {
  max-width: 90vw;
  max-height: 90vh;
  object-fit: contain;
  border-radius: var(--radius-sm);
  cursor: default;
  transform: scale(0.9);
  transition: transform var(--transition-slow);
}

.lightbox.active .lightbox-img {
  transform: scale(1);
}

.post-content img {
  cursor: zoom-in;
}


/* --------------------------------------------------------------------------
   25. Keyboard Shortcuts Overlay
   -------------------------------------------------------------------------- */

.kbd-overlay {
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.6);
  z-index: 250;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-slow);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.kbd-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.kbd-inner {
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  max-width: 420px;
  width: 90%;
  box-shadow: var(--shadow-lg);
  transform: translateY(-16px);
  transition: transform var(--transition-slow);
}

.kbd-overlay.active .kbd-inner {
  transform: translateY(0);
}

.kbd-inner h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 1.25rem;
  color: var(--text-primary);
}

.kbd-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.625rem;
}

.kbd-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.kbd-item kbd {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2rem;
  height: 1.75rem;
  padding: 0 0.5rem;
  font-family: inherit;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  box-shadow: 0 1px 0 var(--border-color);
}

.kbd-item span {
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

.kbd-close {
  display: block;
  width: 100%;
  margin-top: 1.5rem;
  padding: 0.5rem 1rem;
  background-color: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  cursor: pointer;
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.kbd-close:hover {
  background-color: var(--accent);
  color: #ffffff;
  border-color: var(--accent);
}


/* --------------------------------------------------------------------------
   26. Tistory Category Widget
   -------------------------------------------------------------------------- */

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

.sidebar-category .tt_category li {
  margin-bottom: 0.0625rem;
}

.sidebar-category .tt_category a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.4rem 0.5rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: color var(--transition-base), background-color var(--transition-base);
}

.sidebar-category .tt_category a:hover {
  color: var(--accent);
  background-color: var(--accent-light);
}

.sidebar-category .tt_category .link_tit {
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.9375rem;
}

.sidebar-category .tt_category .c_cnt {
  font-size: 0.75rem;
  color: var(--text-tertiary);
  font-weight: 400;
}

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

.sidebar-category .tt_category ul ul {
  padding-left: 1rem;
}

.sidebar-category .tt_category ul ul a {
  font-size: 0.8125rem;
  padding: 0.3rem 0.5rem;
}

.sidebar-category .tt_category ul ul ul {
  padding-left: 0.75rem;
}

.sidebar-category .tt_category ul ul ul a {
  font-size: 0.75rem;
  color: var(--text-tertiary);
}

/* Tistory default category tree widget (table-based) */
.sidebar-category #treeComponent td.branch3 {
  cursor: pointer;
}

.sidebar-category #treeComponent td.branch3 div {
  font-size: 0.875rem;
  padding: 0.3rem 0.25rem;
  border-radius: var(--radius-sm);
  transition: color var(--transition-base), background-color var(--transition-base);
}

.sidebar-category #treeComponent td.branch3:hover div {
  color: var(--accent) !important;
  background-color: var(--accent-light);
}

.sidebar-category #treeComponent .c_cnt {
  font-size: 0.75rem;
  color: var(--text-tertiary) !important;
}

/* Dark mode: override Tistory's inline hardcoded colors */
html.dark .sidebar-category #treeComponent td.branch3 div {
  color: var(--text-secondary) !important;
}

html.dark .sidebar-category #treeComponent table[style*="background-color"] {
  background-color: transparent !important;
}

html.dark .sidebar-category #treeComponent .ib {
  filter: invert(1);
}


/* --------------------------------------------------------------------------
   27. Resume Reading Banner
   -------------------------------------------------------------------------- */

.resume-reading {
  position: fixed;
  bottom: 5rem;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
  z-index: 60;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base), transform var(--transition-base);
}

.resume-reading.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0);
}

.resume-reading-btn {
  padding: 0.375rem 0.875rem;
  background-color: var(--accent);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.resume-reading-btn:hover {
  background-color: var(--accent-hover);
}

.resume-reading-dismiss {
  background: none;
  border: none;
  color: var(--text-tertiary);
  cursor: pointer;
  padding: 0.25rem;
  line-height: 1;
  font-size: 1.125rem;
}

.resume-reading-dismiss:hover {
  color: var(--text-primary);
}


/* --------------------------------------------------------------------------
   28. Utility Classes
   -------------------------------------------------------------------------- */

.sr-only,
.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;
}

.text-center { text-align: center; }
.text-right { text-align: right; }

.flex { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.flex-between { display: flex; align-items: center; justify-content: space-between; }

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }


/* --------------------------------------------------------------------------
   21. Animations
   -------------------------------------------------------------------------- */

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeIn 0.4s ease-out both;
}

.post-card {
  animation: fadeIn 0.4s ease-out both;
}

.post-card:nth-child(1) { animation-delay: 0s; }
.post-card:nth-child(2) { animation-delay: 0.05s; }
.post-card:nth-child(3) { animation-delay: 0.1s; }
.post-card:nth-child(4) { animation-delay: 0.15s; }
.post-card:nth-child(5) { animation-delay: 0.2s; }
.post-card:nth-child(6) { animation-delay: 0.25s; }
.post-card:nth-child(7) { animation-delay: 0.3s; }
.post-card:nth-child(8) { animation-delay: 0.35s; }
.post-card:nth-child(9) { animation-delay: 0.4s; }
.post-card:nth-child(10) { animation-delay: 0.45s; }


/* --------------------------------------------------------------------------
   22. Responsive - 1280px (Large desktop)
   -------------------------------------------------------------------------- */

@media (max-width: 1280px) {
  :root {
    --sidebar-width: 240px;
  }

  .layout {
    gap: 2rem;
  }
}


/* --------------------------------------------------------------------------
   23. Responsive - 1024px (Tablet landscape / small desktop)
   -------------------------------------------------------------------------- */

@media (max-width: 1024px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    display: none;
  }

  .toc {
    position: relative;
    top: 0;
    max-height: none;
    margin-bottom: 2rem;
    padding: 1rem;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
  }

  .toc-mobile-toggle {
    display: flex;
  }

  .toc-list.collapsed {
    display: none;
  }
}


/* --------------------------------------------------------------------------
   24. Responsive - 768px (Tablet portrait)
   -------------------------------------------------------------------------- */

@media (max-width: 768px) {
  h1 { font-size: 1.75rem; }
  h2 { font-size: 1.5rem; }
  h3 { font-size: 1.25rem; }

  .container {
    padding-left: 1rem;
    padding-right: 1rem;
  }

  /* Header mobile */
  .header-nav {
    display: none;
  }

  .hamburger {
    display: flex;
  }

  /* Post cards - vertical stacking */
  .post-card {
    flex-direction: column;
  }

  .post-card .post-thumbnail {
    width: 100%;
    min-height: 0;
    aspect-ratio: 16 / 9;
  }

  .post-card .post-info {
    padding: 1.25rem;
  }

  /* Grid view - single column */
  .post-list.grid-view {
    grid-template-columns: 1fr;
  }

  /* Single post */
  .post-header .post-title {
    font-size: 1.625rem;
  }

  .post-content h2 {
    font-size: 1.5rem;
    margin-top: 2.5rem;
  }

  .post-content h3 {
    font-size: 1.25rem;
    margin-top: 2rem;
  }

  /* Prev/Next navigation */
  .post-navigation {
    flex-direction: column;
  }

  /* Comments */
  .reply-list {
    padding-left: 1.5rem;
  }

  .comment-avatar {
    width: 32px;
    height: 32px;
  }

  .reply-list .comment-avatar {
    width: 28px;
    height: 28px;
  }

  .comment-form {
    padding: 1rem;
  }

  .comment-form .form-row {
    flex-direction: column;
  }

  .comment-form-footer {
    flex-wrap: wrap;
    gap: 0.75rem;
  }

  /* Pagination */
  .pagination a,
  .pagination span {
    width: 36px;
    height: 36px;
    font-size: 0.8125rem;
  }

  /* Search overlay */
  .search-overlay {
    padding: 1rem;
    padding-top: 10vh;
  }

  .search-container {
    border-radius: var(--radius-md);
  }

  /* Cover */
  .cover-section {
    padding: 2rem 0 1.5rem;
  }

  .cover-section .blog-title {
    font-size: 1.625rem;
  }

  .footer {
    margin-top: 2rem;
    padding: 2rem 0;
  }

  .blog-subtitle {
    display: none;
  }
}


/* --------------------------------------------------------------------------
   25. Responsive - 480px (Small mobile)
   -------------------------------------------------------------------------- */

@media (max-width: 480px) {
  :root {
    --header-height: 56px;
  }

  h1 { font-size: 1.5rem; }
  h2 { font-size: 1.25rem; }

  main > .container {
    padding-top: calc(var(--header-height) + 1.5rem);
  }

  .container {
    padding-left: 0.75rem;
    padding-right: 0.75rem;
  }

  .header-inner {
    padding: 0 0.75rem;
  }

  .header-logo a {
    font-size: 1.125rem;
  }

  .btn-icon {
    width: 36px;
    height: 36px;
  }

  /* Post card */
  .post-card .post-info {
    padding: 1rem;
  }

  .post-card .post-title {
    font-size: 1.0625rem;
  }

  .post-card .post-summary {
    font-size: 0.875rem;
    -webkit-line-clamp: 2;
  }

  /* Single post */
  .post-header .post-title {
    font-size: 1.375rem;
  }

  .post-header .post-meta {
    flex-wrap: wrap;
    gap: 0.25rem 0.75rem;
  }

  .post-content {
    font-size: 0.9375rem;
  }

  pre code {
    font-size: 0.8125rem;
    padding: 1rem;
  }

  /* Navigation */
  .post-nav-item {
    padding: 1rem;
  }

  .post-nav-title {
    font-size: 0.875rem;
  }

  /* Back to top */
  .back-to-top {
    width: 42px;
    height: 42px;
    bottom: 1.25rem;
    right: 1.25rem;
  }

  /* Guestbook */
  .guestbook-entry {
    padding: 1rem;
  }

  /* Search */
  .search-input-wrap {
    padding: 0.75rem 1rem;
  }

  .search-input-wrap input {
    font-size: 1rem;
  }
}


/* --------------------------------------------------------------------------
   26. Print Styles
   -------------------------------------------------------------------------- */

@media print {
  .header,
  .sidebar,
  .back-to-top,
  .search-overlay,
  .post-navigation,
  .comments-section,
  .pagination,
  .toc,
  .reading-progress,
  .footer,
  .lightbox,
  .kbd-overlay,
  .resume-reading {
    display: none !important;
  }

  body {
    color: #000;
    background: #fff;
    font-size: 12pt;
    line-height: 1.6;
  }

  .container {
    max-width: 100%;
    padding: 0;
  }

  .post-content a {
    color: #000;
    text-decoration: underline;
  }

  .post-content a::after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
    color: #666;
  }

  pre {
    border: 1px solid #ccc;
    page-break-inside: avoid;
  }

  img {
    page-break-inside: avoid;
  }
}