/* ==========================================================================
   Problem Solving Patterns - Design System & Styles
   ========================================================================== */

:root {
  --font-sans: 'Plus Jakarta Sans', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'Fira Code', 'JetBrains Mono', monospace;

  /* Dark Theme Palette (Default) */
  --bg-main: #0b1120;
  --bg-card: #131d33;
  --bg-surface: #1e293b;
  --bg-surface-hover: #27354d;
  --bg-code: #090e1a;
  
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --border-color: #1e293b;
  --border-subtle: #2d3b55;
  
  --accent-cyan: #38bdf8;
  --accent-cyan-glow: rgba(56, 189, 248, 0.15);
  --accent-gold: #ffa116;
  --accent-emerald: #10b981;
  --accent-rose: #f43f5e;
  --accent-purple: #a855f7;

  --sidebar-width: 320px;
  --toc-width: 260px;
  --header-height: 64px;
  
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.25);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.25);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 20px rgba(56, 189, 248, 0.2);

  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
}

[data-theme="light"] {
  --bg-main: #f8fafc;
  --bg-card: #ffffff;
  --bg-surface: #f1f5f9;
  --bg-surface-hover: #e2e8f0;
  --bg-code: #0f172a;
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  
  --border-color: #e2e8f0;
  --border-subtle: #cbd5e1;
  
  --accent-cyan: #0284c7;
  --accent-cyan-glow: rgba(2, 132, 199, 0.12);
  --accent-gold: #d97706;
  --accent-emerald: #059669;
  --accent-rose: #e11d48;
  --accent-purple: #9333ea;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -2px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.05);
  --shadow-glow: 0 0 20px rgba(2, 132, 199, 0.15);
}

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

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

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

a:hover {
  text-decoration: underline;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 7px;
  height: 7px;
}

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

::-webkit-scrollbar-thumb {
  background: var(--border-subtle);
  border-radius: 4px;
}

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

/* ==========================================================================
   Header Navbar
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  height: var(--header-height);
  background: rgba(11, 17, 32, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
}

[data-theme="light"] .site-header {
  background: rgba(255, 255, 255, 0.85);
}

.header-left {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--text-primary);
  text-decoration: none !important;
}

.brand-icon {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 1rem;
  box-shadow: var(--shadow-glow);
}

.brand-badge {
  font-size: 0.7rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 9999px;
  background: var(--accent-cyan-glow);
  color: var(--accent-cyan);
  border: 1px solid rgba(56, 189, 248, 0.3);
}

.sidebar-toggle-btn {
  display: none;
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

.header-center {
  flex: 1;
  max-width: 440px;
  margin: 0 1.5rem;
}

.search-trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.5rem 0.875rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.search-trigger:hover {
  border-color: var(--accent-cyan);
  color: var(--text-primary);
  box-shadow: 0 0 12px var(--accent-cyan-glow);
}

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

.search-kbd {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  background: var(--bg-surface);
  color: var(--text-muted);
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

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

.header-nav-link {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  text-decoration: none !important;
}

.header-nav-link:hover {
  color: var(--text-primary);
  background: var(--bg-surface);
}

.header-nav-link.accent-link {
  color: var(--accent-cyan);
  font-weight: 600;
}

.icon-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.icon-btn:hover {
  background: var(--bg-surface-hover);
  border-color: var(--accent-cyan);
}

/* ==========================================================================
   Layout Containers
   ========================================================================== */
.app-container {
  display: flex;
  flex: 1;
  min-height: calc(100vh - var(--header-height));
  position: relative;
}

/* ==========================================================================
   Left Sidebar Navigation
   ========================================================================== */
.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  background: var(--bg-card);
  border-right: 1px solid var(--border-color);
  height: calc(100vh - var(--header-height));
  position: sticky;
  top: var(--header-height);
  display: flex;
  flex-direction: column;
  z-index: 30;
  overflow-y: auto;
}

.sidebar-header {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
}

.progress-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.75rem 1rem;
}

.progress-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}

.progress-value {
  color: var(--accent-emerald);
  font-weight: 700;
}

.progress-track {
  width: 100%;
  height: 6px;
  background: var(--bg-main);
  border-radius: 9999px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-emerald), var(--accent-cyan));
  width: 0%;
  transition: width 0.4s ease;
}

.sidebar-filter {
  padding: 0.75rem 1.25rem 0.25rem;
}

.filter-input {
  width: 100%;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.45rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.825rem;
  outline: none;
  transition: border-color var(--transition-fast);
}

.filter-input:focus {
  border-color: var(--accent-cyan);
}

.sidebar-nav {
  flex: 1;
  padding: 0.75rem 0.75rem 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.nav-group-title {
  font-size: 0.725rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  padding: 0.25rem 0.5rem;
}

.pattern-nav-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.pattern-nav-item {
  position: relative;
}

.pattern-nav-link {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-weight: 500;
  text-decoration: none !important;
  transition: all var(--transition-fast);
  border: 1px solid transparent;
}

.pattern-nav-link:hover {
  background: var(--bg-surface);
  color: var(--text-primary);
}

.pattern-nav-item.active .pattern-nav-link {
  background: var(--accent-cyan-glow);
  color: var(--accent-cyan);
  border-color: rgba(56, 189, 248, 0.3);
  font-weight: 600;
}

.nav-num-badge {
  font-family: var(--font-mono);
  font-size: 0.725rem;
  background: var(--bg-surface);
  color: var(--text-muted);
  padding: 1px 5px;
  border-radius: 4px;
  min-width: 24px;
  text-align: center;
}

.pattern-nav-item.active .nav-num-badge {
  background: var(--accent-cyan);
  color: #0b1120;
  font-weight: 700;
}

.nav-item-title {
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.nav-check-icon {
  color: var(--accent-emerald);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.pattern-nav-item.mastered .nav-check-icon {
  opacity: 1;
}

/* ==========================================================================
   Main Content Rail
   ========================================================================== */
.main-wrapper {
  flex: 1;
  min-width: 0;
  display: flex;
  justify-content: center;
  position: relative;
}

.main-content {
  width: 100%;
  max-width: 900px;
  padding: 2.5rem 2rem 5rem;
  min-width: 0;
}

/* Overview / Hero Banner */
.pattern-hero {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-bottom: 2.5rem;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.pattern-hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-purple), var(--accent-emerald));
}

.hero-meta-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

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

.badge {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.25rem 0.625rem;
  border-radius: 9999px;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.badge-core {
  background: rgba(56, 189, 248, 0.12);
  color: var(--accent-cyan);
  border: 1px solid rgba(56, 189, 248, 0.25);
}

.badge-advanced {
  background: rgba(168, 85, 247, 0.12);
  color: var(--accent-purple);
  border: 1px solid rgba(168, 85, 247, 0.25);
}

.badge-difficulty {
  background: rgba(255, 161, 22, 0.12);
  color: var(--accent-gold);
  border: 1px solid rgba(255, 161, 22, 0.25);
}

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

.mastered-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.825rem;
  font-weight: 600;
  padding: 0.4rem 0.875rem;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
}

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

.mastered-btn.active {
  background: rgba(16, 185, 129, 0.15);
  color: var(--accent-emerald);
  border-color: rgba(16, 185, 129, 0.35);
}

.hero-title {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.25;
  color: var(--text-primary);
  margin-bottom: 0.875rem;
}

.hero-keyidea {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Home Overview Landing View */
.landing-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.25rem;
  margin-top: 1.5rem;
}

.pattern-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  text-decoration: none !important;
  color: inherit;
  display: flex;
  flex-direction: column;
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.pattern-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent-cyan);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}

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

.card-icon {
  font-size: 1.5rem;
}

.card-num {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-cyan);
  background: var(--accent-cyan-glow);
  padding: 2px 6px;
  border-radius: 4px;
}

.card-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
  line-height: 1.35;
}

.card-idea {
  font-size: 0.825rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 1rem;
  flex: 1;
}

.card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border-color);
  padding-top: 0.75rem;
}

/* ==========================================================================
   Markdown Render Styles
   ========================================================================== */
.markdown-body {
  color: var(--text-primary);
  font-size: 1rem;
  line-height: 1.75;
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4 {
  color: var(--text-primary);
  font-weight: 700;
  line-height: 1.3;
  margin-top: 2rem;
  margin-bottom: 0.875rem;
  position: relative;
  scroll-margin-top: calc(var(--header-height) + 1.5rem);
}

.markdown-body h1 {
  font-size: 1.75rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.5rem;
}

.markdown-body h2 {
  font-size: 1.4rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.4rem;
}

.markdown-body h3 {
  font-size: 1.15rem;
}

.markdown-body h4 {
  font-size: 1rem;
}

.markdown-body p {
  margin-bottom: 1.125rem;
  color: var(--text-primary);
}

.markdown-body ul,
.markdown-body ol {
  margin-bottom: 1.25rem;
  padding-left: 1.5rem;
}

.markdown-body li {
  margin-bottom: 0.375rem;
}

.markdown-body blockquote {
  border-left: 3px solid var(--accent-cyan);
  background: var(--accent-cyan-glow);
  padding: 0.875rem 1.25rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 1.5rem 0;
  color: var(--text-primary);
  font-style: normal;
}

.markdown-body hr {
  border: 0;
  height: 1px;
  background: var(--border-color);
  margin: 2.5rem 0;
}

.markdown-body img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  margin: 1.5rem auto;
  display: block;
  box-shadow: var(--shadow-md);
  background: #0f172a;
}

.markdown-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.9rem;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border-color);
}

.markdown-body th,
.markdown-body td {
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-color);
  text-align: left;
}

.markdown-body th {
  background: var(--bg-surface);
  font-weight: 600;
  color: var(--text-primary);
}

.markdown-body tr:hover td {
  background: var(--bg-surface-hover);
}

/* Inline code */
.markdown-body code:not([class*="language-"]) {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--bg-surface);
  color: var(--accent-cyan);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

/* Code Blocks Container */
.code-block-wrapper {
  position: relative;
  margin: 1.5rem 0;
  border-radius: var(--radius-md);
  background: var(--bg-code);
  border: 1px solid var(--border-color);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.code-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5rem 1rem;
  background: rgba(30, 41, 59, 0.6);
  border-bottom: 1px solid var(--border-color);
  font-size: 0.75rem;
  font-family: var(--font-mono);
  color: var(--text-secondary);
}

.code-lang-tag {
  text-transform: uppercase;
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--accent-cyan);
}

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

.code-copy-btn {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-secondary);
  font-size: 0.75rem;
  padding: 3px 8px;
  border-radius: 4px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.35rem;
  transition: all var(--transition-fast);
}

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

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

pre[class*="language-"] {
  margin: 0 !important;
  padding: 1rem !important;
  background: transparent !important;
  font-family: var(--font-mono) !important;
  font-size: 0.85rem !important;
  line-height: 1.6 !important;
  overflow-x: auto;
}

/* ==========================================================================
   Bottom Navigation Pager
   ========================================================================== */
.pattern-pager {
  display: flex;
  justify-content: space-between;
  gap: 1.5rem;
  margin-top: 3.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.pager-btn {
  flex: 1;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  text-decoration: none !important;
  transition: all var(--transition-normal);
}

.pager-btn:hover {
  border-color: var(--accent-cyan);
  background: var(--bg-surface);
  transform: translateY(-2px);
}

.pager-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.pager-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.pager-btn.next {
  text-align: right;
}

.pager-btn.next .pager-label {
  justify-content: flex-end;
}

/* ==========================================================================
   Right Table of Contents (TOC)
   ========================================================================== */
.toc-sidebar {
  width: var(--toc-width);
  min-width: var(--toc-width);
  height: calc(100vh - var(--header-height));
  position: sticky;
  top: var(--header-height);
  padding: 2.5rem 1.5rem 2rem 0.5rem;
  overflow-y: auto;
  font-size: 0.825rem;
}

.toc-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.toc-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  border-left: 1px solid var(--border-color);
  padding-left: 0.75rem;
}

.toc-item a {
  display: block;
  color: var(--text-secondary);
  text-decoration: none !important;
  line-height: 1.4;
  padding: 0.2rem 0;
  transition: color var(--transition-fast);
}

.toc-item.h3 a {
  padding-left: 0.75rem;
  font-size: 0.775rem;
}

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

.toc-item.active a {
  color: var(--accent-cyan);
  font-weight: 600;
}

/* ==========================================================================
   Search Modal
   ========================================================================== */
.search-modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(11, 17, 32, 0.75);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 100;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 4rem 1rem 2rem;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-fast);
}

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

.search-modal {
  width: 100%;
  max-width: 600px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg), var(--shadow-glow);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  max-height: 80vh;
  transform: translateY(-10px);
  transition: transform var(--transition-fast);
}

.search-modal-backdrop.open .search-modal {
  transform: translateY(0);
}

.search-input-wrapper {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
}

.search-icon {
  color: var(--accent-cyan);
  flex-shrink: 0;
}

.search-input {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-size: 1.05rem;
  outline: none;
  font-family: inherit;
}

.search-results-list {
  list-style: none;
  overflow-y: auto;
  padding: 0.5rem;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.search-result-item {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-md);
  text-decoration: none !important;
  color: inherit;
  cursor: pointer;
  transition: background var(--transition-fast);
}

.search-result-item:hover,
.search-result-item.selected {
  background: var(--bg-surface);
}

.search-result-item.selected {
  border-left: 3px solid var(--accent-cyan);
}

.search-result-icon {
  font-size: 1.25rem;
  margin-top: 2px;
}

.search-result-info {
  flex: 1;
  min-width: 0;
}

.search-result-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.2rem;
}

.search-result-snippet {
  font-size: 0.8rem;
  color: var(--text-secondary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.search-empty {
  padding: 2.5rem 1rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.search-footer {
  padding: 0.625rem 1rem;
  background: var(--bg-surface);
  border-top: 1px solid var(--border-color);
  font-size: 0.75rem;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* ==========================================================================
   Mobile & Responsive Styles
   ========================================================================== */
@media (max-width: 1200px) {
  .toc-sidebar {
    display: none;
  }
}

@media (max-width: 900px) {
  .sidebar-toggle-btn {
    display: flex;
  }

  .sidebar {
    position: fixed;
    top: var(--header-height);
    left: -100%;
    width: 280px;
    transition: left 0.3s ease;
    box-shadow: var(--shadow-lg);
  }

  .sidebar.open {
    left: 0;
  }

  .main-content {
    padding: 1.5rem 1rem 4rem;
  }

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

  .header-center {
    display: none;
  }
}