/* =============================================================================
   AUTOMATED TRADING SYSTEM DOCS — STYLE SYSTEM
   Inter-based, gradient accent, dark mode, responsive three-breakpoint layout
   ============================================================================= */

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

/* === Custom Properties — Light Mode (default) === */
:root {
  --bg: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-code: #f1f5f9;
  --bg-card: #ffffff;
  --text: #0f172a;
  --text-muted: #64748b;
  --text-faint: #94a3b8;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-2: #7c3aed;
  --accent-light: #eff6ff;
  --accent-gradient: linear-gradient(135deg, #2563eb, #7c3aed);
  --accent-gradient-text: linear-gradient(135deg, #2563eb 0%, #7c3aed 100%);
  --border: #e2e8f0;
  --border-light: #f1f5f9;
  --sidebar-bg: #f8fafc;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.04);
  --shadow-card: 0 1px 3px rgba(0,0,0,0.06), 0 0 0 1px rgba(0,0,0,0.03);
  --overlay-bg: rgba(0, 0, 0, 0.7);
  --sidebar-width: 280px;
  --header-height: 60px;
  --progress-height: 3px;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: "SF Mono", "Cascadia Code", "Fira Code", Consolas, monospace;
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --transition-fast: 0.15s ease;
  --transition-base: 0.25s ease;
  --transition-slow: 0.35s ease;
  --toc-width: 240px;
}

/* === Custom Properties — Dark Mode === */
[data-theme="dark"] {
  --bg: #0f172a;
  --bg-secondary: #1e293b;
  --bg-code: #1e293b;
  --bg-card: #1e293b;
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --text-faint: #64748b;
  --accent: #60a5fa;
  --accent-hover: #93bbfd;
  --accent-2: #a78bfa;
  --accent-light: rgba(96, 165, 250, 0.1);
  --accent-gradient: linear-gradient(135deg, #60a5fa, #a78bfa);
  --accent-gradient-text: linear-gradient(135deg, #60a5fa 0%, #a78bfa 100%);
  --border: #334155;
  --border-light: #1e293b;
  --sidebar-bg: #1e293b;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.4), 0 2px 4px -2px rgba(0,0,0,0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.5), 0 4px 6px -4px rgba(0,0,0,0.3);
  --shadow-card: 0 1px 3px rgba(0,0,0,0.3), 0 0 0 1px rgba(255,255,255,0.03);
  --overlay-bg: rgba(0, 0, 0, 0.85);
}

/* === Base Typography === */
html {
  font-size: 16px;
  line-height: 1.7;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + var(--progress-height) + 1rem);
}

body {
  font-family: var(--font-sans);
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background var(--transition-base), color var(--transition-base);
}

/* === Scroll Progress Bar === */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: var(--progress-height);
  width: 0%;
  background: var(--accent-gradient);
  z-index: 1000;
  transition: none;
  pointer-events: none;
}

/* === Header === */
header {
  position: fixed;
  top: var(--progress-height);
  left: 0;
  right: 0;
  height: var(--header-height);
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  z-index: 100;
  display: flex;
  align-items: center;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transition: background var(--transition-base), border-color var(--transition-base);
}

[data-theme="dark"] header {
  background: rgba(15, 23, 42, 0.92);
}

[data-theme="light"] header {
  background: rgba(255, 255, 255, 0.92);
}

.header-inner {
  width: 100%;
  max-width: 1600px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.site-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  white-space: nowrap;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: color var(--transition-fast);
}

.site-title:hover {
  color: var(--accent);
}

.site-title-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.75rem;
  height: 1.75rem;
  background: var(--accent-gradient);
  color: #fff;
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  flex-shrink: 0;
}

.menu-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 1.25rem;
  padding: 0.25rem 0.6rem;
  cursor: pointer;
  color: var(--text);
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.menu-toggle:hover {
  background: var(--bg-secondary);
}

/* === Search === */
#search {
  flex: 1;
  max-width: 400px;
  margin-left: auto;
}

#search .pagefind-ui {
  font-family: var(--font-sans);
}

/* === Header Actions (theme + toc toggles) === */
.header-actions {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  flex-shrink: 0;
}

.theme-toggle,
.toc-toggle-btn {
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  color: var(--text-muted);
  padding: 0.35rem 0.5rem;
  font-size: 1rem;
  line-height: 1;
  transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-toggle:hover,
.toc-toggle-btn:hover {
  background: var(--bg-secondary);
  color: var(--accent);
  border-color: var(--accent);
}

.toc-toggle-btn {
  display: none;
  font-size: 0.85rem;
}

.toc-toggle-btn.visible {
  display: flex;
}

/* Theme icon switching */
.theme-icon-dark { display: none; }
.theme-icon-light { display: inline; }

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

/* === Layout Container === */
.container {
  display: flex;
  margin-top: calc(var(--header-height) + var(--progress-height));
  min-height: calc(100vh - var(--header-height) - var(--progress-height));
}

/* === Sidebar === */
.sidebar {
  position: fixed;
  top: calc(var(--header-height) + var(--progress-height));
  left: 0;
  bottom: 0;
  width: var(--sidebar-width);
  overflow-y: auto;
  overflow-x: hidden;
  padding: 1.25rem 0.75rem;
  border-right: 1px solid var(--border);
  background: var(--sidebar-bg);
  font-size: 0.8125rem;
  z-index: 50;
  transition: background var(--transition-base), border-color var(--transition-base), transform var(--transition-base);
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

.sidebar::-webkit-scrollbar {
  width: 4px;
}

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

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

/* Sidebar links */
.sidebar a {
  color: var(--text-muted);
  text-decoration: none;
  display: block;
  padding: 0.375rem 0.75rem;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background var(--transition-fast), border-color var(--transition-fast), padding var(--transition-fast);
  border-left: 3px solid transparent;
  line-height: 1.4;
}

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

.sidebar a.active {
  color: var(--accent);
  font-weight: 600;
  border-left-color: var(--accent);
  background: var(--accent-light);
}

/* Sidebar sections (collapsible) */
.sidebar-section {
  margin-bottom: 0.125rem;
}

.sidebar details summary {
  list-style: none;
  cursor: pointer;
  padding: 0.1rem 0;
  display: flex;
  align-items: center;
  user-select: none;
}

.sidebar details summary::before {
  content: "\25B6";
  font-size: 0.55rem;
  margin-right: 0.35rem;
  transition: transform var(--transition-base);
  flex-shrink: 0;
  color: var(--text-faint);
}

.sidebar details[open] summary::before {
  transform: rotate(90deg);
}

.sidebar details summary::-webkit-details-marker {
  display: none;
}

.sidebar details ul {
  list-style: none;
  padding-left: 0.75rem;
  margin: 0.1rem 0 0.5rem;
  overflow: hidden;
  transition: max-height var(--transition-slow), opacity var(--transition-base);
}

.sidebar details ul li {
  margin: 0.05rem 0;
}

.sidebar .nav-item {
  margin-bottom: 0.125rem;
}

/* === Main Content === */
main {
  margin-left: var(--sidebar-width);
  flex: 1;
  min-width: 0;
  padding: 2rem 2.5rem 4rem;
  display: flex;
  gap: 2rem;
  transition: margin var(--transition-base);
}

main article {
  max-width: 900px;
  flex: 1;
  min-width: 0;
}

/* === Breadcrumb === */
.breadcrumb {
  display: none;
  align-items: center;
  flex-wrap: wrap;
  font-size: 0.8125rem;
  margin-bottom: 1rem;
  color: var(--text-muted);
  gap: 0;
}

.breadcrumb.visible {
  display: flex;
}

.breadcrumb a {
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

.breadcrumb-sep {
  margin: 0 0.25rem;
  color: var(--text-faint);
}

.breadcrumb-current {
  color: var(--text);
  font-weight: 500;
}

/* === Page Header === */
.page-header {
  margin-bottom: 2rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--border);
  transition: border-color var(--transition-base);
}

.page-title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text);
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
  transition: color var(--transition-base);
}

.reading-time {
  font-size: 0.8125rem;
  color: var(--text-faint);
  font-weight: 500;
}

/* === Article Content — Typography === */
.article-content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 2.5rem 0 1rem;
  padding: 0 0 0.4rem;
  color: var(--text);
  line-height: 1.3;
  letter-spacing: -0.01em;
  border-bottom: 2px solid var(--border);
  transition: border-color var(--transition-base), color var(--transition-base);
}

.article-content h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 2rem 0 0.625rem;
  color: var(--text);
  line-height: 1.35;
  transition: color var(--transition-base);
}

.article-content h4 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin: 1.5rem 0 0.5rem;
  color: var(--text);
  transition: color var(--transition-base);
}

.article-content h5,
.article-content h6 {
  font-size: 0.9375rem;
  font-weight: 600;
  margin: 1.25rem 0 0.375rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  transition: color var(--transition-base);
}

.article-content p {
  margin-bottom: 1rem;
  line-height: 1.7;
}

.article-content ul,
.article-content ol {
  margin: 0 0 1rem 1.5rem;
  line-height: 1.7;
}

.article-content li {
  margin-bottom: 0.3rem;
}

.article-content li > ul,
.article-content li > ol {
  margin-top: 0.3rem;
  margin-bottom: 0;
}

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

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

.article-content strong {
  font-weight: 600;
  color: var(--text);
}

/* === Blockquotes === */
.article-content blockquote {
  border-left: 3px solid var(--accent);
  padding: 0.5rem 1rem;
  margin: 1.25rem 0;
  background: none;
  color: var(--text-muted);
  font-style: italic;
  transition: border-color var(--transition-base), color var(--transition-base);
}

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

/* === Horizontal Rules === */
.article-content hr {
  border: none;
  height: 1px;
  background: var(--border);
  margin: 2.5rem 0;
  transition: background var(--transition-base);
}

/* === Tables === */
.article-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.25rem 0 1.75rem;
  font-size: 0.8125rem;
  display: block;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  transition: border-color var(--transition-base);
}

.article-content thead {
  background: none;
  position: sticky;
  top: 0;
  z-index: 2;
  transition: background var(--transition-base);
}

.article-content th,
.article-content td {
  border: none;
  border-bottom: 1px solid var(--border-light);
  padding: 0.5rem 0.875rem;
  text-align: left;
  white-space: nowrap;
  transition: background var(--transition-base), border-color var(--transition-base);
}

.article-content th {
  font-weight: 600;
  color: var(--text);
  font-size: 0.8125rem;
  letter-spacing: 0.01em;
  border-bottom: 2px solid var(--border);
}

.article-content tbody tr {
  transition: background var(--transition-fast);
}

.article-content tbody tr:nth-child(even) {
  background: none;
}

.article-content tbody tr:hover {
  background: var(--accent-light);
}

/* Table scroll fade indicators */
.article-content table::before,
.article-content table::after {
  content: '';
  position: sticky;
  top: 0;
  bottom: 0;
  width: 2rem;
  pointer-events: none;
  z-index: 3;
}

/* === Code — Inline === */
.article-content code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--bg-code);
  padding: 0.15rem 0.4rem;
  border-radius: 3px;
  border: none;
  transition: background var(--transition-base);
  word-break: break-word;
}

/* === Code — Blocks === */
.article-content pre {
  background: var(--bg-code);
  border: none;
  border-radius: var(--radius-sm);
  padding: 1rem 1.25rem;
  overflow-x: auto;
  margin: 1.25rem 0 1.75rem;
  line-height: 1.6;
  transition: background var(--transition-base);
  counter-reset: line;
}

.article-content pre code {
  background: none;
  padding: 0;
  font-size: 0.8125rem;
  border: none;
  display: block;
}

/* Line numbers on hover */
.article-content pre:not(.mermaid):hover code {
  padding-left: 2.5em;
}

.article-content pre:not(.mermaid):hover code::before {
  content: counter(line);
  counter-increment: line;
  position: absolute;
  left: 0.75rem;
  color: var(--text-faint);
  font-size: 0.75rem;
  width: 1.5em;
  text-align: right;
  user-select: none;
}

/* Copy button for code blocks */
.code-copy-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.5rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  font-size: 0.7rem;
  font-family: var(--font-sans);
  padding: 0.25rem 0.6rem;
  cursor: pointer;
  opacity: 0;
  transition: opacity var(--transition-fast), background var(--transition-fast), color var(--transition-fast);
  z-index: 2;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

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

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

.code-copy-btn.copied {
  background: #059669;
  color: #fff;
  border-color: #059669;
}

/* === Mermaid Diagrams === */
pre.mermaid {
  background: none;
  border: none;
  text-align: center;
  padding: 1.5rem 1rem;
  max-width: 100%;
  margin: 1.5rem auto;
  border-radius: var(--radius-lg);
  box-shadow: none;
}

pre.mermaid svg {
  max-width: 100%;
  filter: drop-shadow(0 2px 8px rgba(0, 0, 0, 0.08));
}

[data-theme="dark"] pre.mermaid svg {
  filter: drop-shadow(0 2px 8px rgba(0, 0, 0, 0.3));
}

/* === Images === */
.article-content img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
  margin: 0.75rem 0;
  transition: opacity var(--transition-base);
}

.article-content img:hover {
  opacity: 0.92;
}

/* === Table of Contents Panel === */
.toc-panel {
  display: none;
  position: sticky;
  top: calc(var(--header-height) + var(--progress-height) + 2rem);
  width: var(--toc-width);
  max-height: calc(100vh - var(--header-height) - var(--progress-height) - 4rem);
  overflow-y: auto;
  flex-shrink: 0;
  font-size: 0.8125rem;
  align-self: flex-start;
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

.toc-panel.has-toc {
  display: block;
}

.toc-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 0.625rem;
  margin-bottom: 0.625rem;
  border-bottom: 1px solid var(--border);
  color: var(--text-faint);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  transition: border-color var(--transition-base), color var(--transition-base);
}

.toc-close {
  display: none;
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 1.25rem;
  cursor: pointer;
  line-height: 1;
  padding: 0.125rem;
}

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

.toc-list li {
  margin: 0;
}

.toc-list li.toc-sub {
  padding-left: 0.875rem;
}

.toc-list a {
  display: block;
  padding: 0.25rem 0.625rem;
  color: var(--text-faint);
  text-decoration: none;
  border-left: 2px solid transparent;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  transition: color var(--transition-fast), border-color var(--transition-fast), background var(--transition-fast);
  line-height: 1.4;
  font-size: 0.78rem;
}

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

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

/* === Previous / Next Page Navigation === */
.page-nav {
  display: flex;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  transition: border-color var(--transition-base);
}

.page-nav-link {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 0.75rem 0;
  background: none;
  border: none;
  text-decoration: none;
  transition: color var(--transition-fast);
}

.page-nav-link:hover .page-nav-title {
  color: var(--accent-hover);
}

.page-nav-placeholder {
  border: none;
  background: none;
}

.page-nav-next {
  text-align: right;
  align-items: flex-end;
}

.page-nav-direction {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-faint);
}

.page-nav-title {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--accent);
}

/* === Back to Top Button === */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  background: var(--accent-gradient);
  color: #fff;
  border: none;
  font-size: 1.125rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transform: translateY(1rem);
  pointer-events: none;
  transition: opacity var(--transition-base), transform var(--transition-base), box-shadow var(--transition-fast);
  box-shadow: var(--shadow-md);
  z-index: 90;
}

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

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

/* === Image Lightbox === */
.lightbox-overlay {
  position: fixed;
  inset: 0;
  background: var(--overlay-bg);
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-base), visibility var(--transition-base);
  cursor: zoom-out;
}

.lightbox-overlay.active {
  opacity: 1;
  visibility: visible;
}

.lightbox-img {
  max-width: 92vw;
  max-height: 92vh;
  object-fit: contain;
  border-radius: var(--radius-md);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
  transform: scale(0.92);
  transition: transform var(--transition-base);
  cursor: default;
}

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

.lightbox-close {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  background: rgba(255, 255, 255, 0.15);
  border: none;
  color: #fff;
  font-size: 2rem;
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition-fast);
  backdrop-filter: blur(8px);
}

.lightbox-close:hover {
  background: rgba(255, 255, 255, 0.3);
}

/* === Footer === */
.site-footer {
  margin-left: var(--sidebar-width);
  border-top: 1px solid var(--border);
  background: none;
  padding: 2rem 2.5rem;
  font-size: 0.8125rem;
  color: var(--text-muted);
  transition: border-color var(--transition-base), color var(--transition-base), margin var(--transition-base);
}

.footer-inner {
  max-width: 900px;
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  align-items: flex-start;
}

.footer-col {
  flex: 1;
  min-width: 180px;
}

.footer-copyright {
  font-weight: 600;
  color: var(--text);
  margin-bottom: 0.25rem;
  transition: color var(--transition-base);
}

.footer-updated {
  color: var(--text-faint);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
}

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

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

.footer-shortcuts {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.shortcut-hint {
  color: var(--text-faint);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.shortcut-hint kbd {
  display: inline-block;
  padding: 0.1rem 0.4rem;
  font-size: 0.6875rem;
  font-family: var(--font-mono);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  box-shadow: 0 1px 0 var(--border);
  min-width: 1.5em;
  text-align: center;
  transition: background var(--transition-base), border-color var(--transition-base);
}

/* === Responsive — Tablet (768px - 1200px) === */
@media (max-width: 1200px) {
  .toc-panel {
    display: none;
    position: fixed;
    top: calc(var(--header-height) + var(--progress-height));
    right: 0;
    bottom: 0;
    width: 280px;
    max-height: none;
    background: var(--bg);
    border-left: 1px solid var(--border);
    padding: 1.25rem;
    z-index: 80;
    box-shadow: var(--shadow-lg);
    transform: translateX(100%);
    transition: transform var(--transition-base), background var(--transition-base), border-color var(--transition-base);
  }

  .toc-panel.has-toc {
    display: block;
  }

  .toc-panel.open {
    transform: translateX(0);
  }

  .toc-close {
    display: block;
  }

  main {
    padding: 1.5rem 2rem 3rem;
  }
}

/* === Responsive — Mobile (<768px) === */
@media (max-width: 768px) {
  :root {
    --sidebar-width: 280px;
    --header-height: 56px;
  }

  .menu-toggle {
    display: block;
  }

  .sidebar {
    transform: translateX(-100%);
    width: 280px;
    box-shadow: none;
  }

  .sidebar.open {
    transform: translateX(0);
    box-shadow: 4px 0 24px rgba(0, 0, 0, 0.15);
  }

  main {
    margin-left: 0;
    padding: 1.25rem 1rem 3rem;
    flex-direction: column;
  }

  .site-footer {
    margin-left: 0;
    padding: 1.5rem 1rem;
  }

  .footer-inner {
    flex-direction: column;
    gap: 1rem;
  }

  .page-title {
    font-size: 1.625rem;
  }

  .article-content h2 {
    font-size: 1.25rem;
  }

  .article-content h3 {
    font-size: 1.0625rem;
  }

  .article-content th,
  .article-content td {
    padding: 0.375rem 0.5rem;
    font-size: 0.75rem;
  }

  #search {
    display: none;
  }

  .page-nav {
    flex-direction: column;
  }

  .page-nav-next {
    text-align: left;
    align-items: flex-start;
  }

  .back-to-top {
    bottom: 1.25rem;
    right: 1.25rem;
    width: 2.25rem;
    height: 2.25rem;
  }

  .toc-toggle-btn.visible {
    display: flex;
  }

  .toc-panel {
    width: 100%;
    right: 0;
  }

  .footer-shortcuts {
    display: none;
  }

  .header-actions {
    gap: 0.25rem;
  }
}

/* === Print Styles === */
@media print {
  .scroll-progress,
  header,
  .sidebar,
  .menu-toggle,
  #search,
  .theme-toggle,
  .toc-toggle-btn,
  .back-to-top,
  .lightbox-overlay,
  .code-copy-btn,
  .page-nav,
  .footer-shortcuts,
  .header-actions {
    display: none !important;
  }

  html {
    font-size: 11pt;
  }

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

  main {
    margin-left: 0;
    padding: 0;
    max-width: 100%;
    display: block;
  }

  .container {
    display: block;
    margin-top: 0;
  }

  .site-footer {
    margin-left: 0;
    background: none;
    border-top: 1px solid #ccc;
    padding: 1rem 0;
  }

  .page-title {
    font-size: 22pt;
  }

  .article-content h2 {
    border-bottom: 2px solid #000;
    padding: 0 0 0.25rem;
    margin: 1.5rem 0 0.75rem;
    page-break-after: avoid;
  }

  .article-content h3 {
    page-break-after: avoid;
  }

  .article-content table {
    font-size: 9pt;
  }

  .article-content pre {
    border: 1px solid #ccc;
    font-size: 8pt;
    page-break-inside: avoid;
  }

  .article-content img {
    max-width: 100%;
    page-break-inside: avoid;
  }

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

  .article-content a::after {
    content: " [" attr(href) "]";
    font-size: 0.8em;
    color: #555;
  }

  .article-content a[href^="#"]::after {
    content: "";
  }

  /* Print TOC */
  .toc-panel {
    display: block !important;
    position: static !important;
    width: 100% !important;
    max-height: none !important;
    transform: none !important;
    border: 1px solid #ccc;
    padding: 1rem;
    margin: 1rem 0;
    page-break-inside: avoid;
  }

  .toc-panel.has-toc {
    display: block !important;
  }

  .toc-close {
    display: none !important;
  }

  .toc-list a {
    color: #000;
  }

  .breadcrumb {
    font-size: 9pt;
    margin-bottom: 0.5rem;
  }

  .reading-time {
    display: none;
  }
}

/* === Selection === */
::selection {
  background: var(--accent-light);
  color: var(--accent);
}

[data-theme="dark"] ::selection {
  background: rgba(96, 165, 250, 0.25);
}

/* === Focus Styles (accessibility) === */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* === Smooth transitions on theme change === */
header,
.sidebar,
.sidebar a,
main,
.site-footer,
.page-title,
.breadcrumb,
.reading-time,
.article-content h2,
.article-content h3,
.article-content h4,
.article-content blockquote,
.article-content table,
.article-content thead,
.article-content th,
.article-content td,
.article-content code,
.article-content pre,
.page-nav,
.page-nav-link,
.toc-panel,
.toc-header,
.toc-list a,
.shortcut-hint kbd {
  transition-property: background, background-color, color, border-color, box-shadow;
  transition-duration: 0.25s;
  transition-timing-function: ease;
}

/* === Pagefind overrides for dark mode === */
[data-theme="dark"] .pagefind-ui__search-input {
  background: var(--bg-secondary);
  color: var(--text);
  border-color: var(--border);
}

[data-theme="dark"] .pagefind-ui__result {
  border-color: var(--border);
}

[data-theme="dark"] .pagefind-ui__result-link {
  color: var(--accent);
}

[data-theme="dark"] .pagefind-ui__result-excerpt {
  color: var(--text-muted);
}

/* === Scrollbar global === */
body {
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

body::-webkit-scrollbar {
  width: 8px;
}

body::-webkit-scrollbar-track {
  background: transparent;
}

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

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