:root {
  --bg: #0f1117;
  --bg-elevated: #161b26;
  --bg-hover: #1c2333;
  --border: #2a3347;
  --text: #e8ecf4;
  --text-muted: #8b95a8;
  --accent: #3b82f6;
  --accent-hover: #60a5fa;
  --accent-glow: rgba(59, 130, 246, 0.15);
  --success: #22c55e;
  --sidebar-w: 280px;
  --topbar-h: 56px;
  --radius: 10px;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --mono: 'JetBrains Mono', ui-monospace, monospace;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

/* Layout */
.layout { display: flex; min-height: 100vh; }

.sidebar {
  position: fixed;
  top: 0; left: 0; bottom: 0;
  width: var(--sidebar-w);
  background: var(--bg-elevated);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  z-index: 100;
  overflow: hidden;
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border);
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--text);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
}
.brand:hover { text-decoration: none; color: var(--accent-hover); }
.brand-icon { color: var(--accent); display: flex; }

.sidebar-close { display: none; background: none; border: none; color: var(--text-muted); font-size: 1.2rem; cursor: pointer; }

.search-form {
  position: relative;
  margin: 0.75rem 1rem;
}
.search-form input {
  width: 100%;
  padding: 0.55rem 0.75rem 0.55rem 2.2rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-size: 0.875rem;
  outline: none;
  transition: border-color 0.15s;
}
.search-form input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-glow); }
.search-icon { position: absolute; left: 0.7rem; top: 50%; transform: translateY(-50%); color: var(--text-muted); pointer-events: none; }

.nav-tree {
  padding: 0.25rem 0.5rem 1.25rem 0.75rem;
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: rgba(96, 165, 250, 0.45) transparent;
}

.nav-tree::-webkit-scrollbar {
  width: 5px;
}

.nav-tree::-webkit-scrollbar-track {
  background: transparent;
  margin: 6px 0;
}

.nav-tree::-webkit-scrollbar-thumb {
  background: linear-gradient(180deg, rgba(59, 130, 246, 0.55), rgba(96, 165, 250, 0.3));
  border-radius: 999px;
}

.nav-tree::-webkit-scrollbar-thumb:hover {
  background: linear-gradient(180deg, rgba(96, 165, 250, 0.75), rgba(59, 130, 246, 0.45));
}

.nav-section {
  margin-top: 1.125rem;
  padding-top: 0.875rem;
  border-top: 1px solid var(--border);
}

.nav-section:first-of-type {
  margin-top: 0.625rem;
  padding-top: 0;
  border-top: none;
}

.nav-section-title {
  display: block;
  padding: 0.15rem 0.75rem 0.45rem;
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--text);
  text-decoration: none;
}
.nav-section-title:hover {
  color: var(--accent-hover);
  text-decoration: none;
}
.nav-section-title.active {
  color: var(--accent-hover);
}

.nav-link {
  display: block;
  padding: 0.32rem 0.65rem 0.32rem 1.35rem;
  font-size: 0.8125rem;
  font-weight: 400;
  color: var(--text-muted);
  border-radius: 6px;
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: color 0.12s, background 0.12s, border-color 0.12s;
}
.nav-link:hover { color: var(--text); background: var(--bg-hover); text-decoration: none; }
.nav-link.active {
  color: var(--accent-hover);
  background: var(--accent-glow);
  border-left-color: var(--accent);
  font-weight: 500;
}

/* «Главная» — отдельно от разделов */
.nav-tree > .nav-link {
  margin-bottom: 0.25rem;
  padding-left: 0.75rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text);
}

.main {
  flex: 1;
  margin-left: var(--sidebar-w);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  gap: 1rem;
  height: var(--topbar-h);
  padding: 0 2rem;
  background: rgba(15, 17, 23, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.menu-btn {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.4rem;
  color: var(--text);
  cursor: pointer;
}

.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
}
.breadcrumbs a { color: var(--text-muted); }
.breadcrumbs a:hover { color: var(--accent-hover); }
.breadcrumbs .sep { opacity: 0.4; }
.breadcrumbs .current { color: var(--text); font-weight: 500; }

.content {
  flex: 1;
  max-width: 820px;
  width: 100%;
  margin: 0 auto;
  padding: 1.5rem 2rem 2.5rem;
}

.footer {
  margin-top: auto;
  padding: 1.5rem 2rem 1.75rem;
  border-top: 1px solid var(--border);
  background: linear-gradient(180deg, transparent, rgba(22, 27, 38, 0.6));
}

.footer-inner {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 1.25rem 2rem;
}

.footer-meta {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

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

.footer-sitemap {
  font-size: 0.78rem;
  color: var(--text-muted);
  text-decoration: none;
}
.footer-sitemap:hover { color: var(--accent-hover); text-decoration: none; }

.footer-contacts {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 0.55rem;
}

.footer-contacts-label {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--text-muted);
}

.footer-contacts-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: flex-end;
}

.footer-contact {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.45rem 0.85rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--text);
  font-size: 0.8125rem;
  text-decoration: none;
  transition: border-color 0.15s, box-shadow 0.15s, color 0.15s;
}
.footer-contact:hover {
  border-color: rgba(96, 165, 250, 0.45);
  box-shadow: 0 2px 16px var(--accent-glow);
  color: var(--accent-hover);
  text-decoration: none;
}

.footer-contact-icon {
  display: flex;
  color: var(--accent-hover);
  flex-shrink: 0;
}
.footer-contact-icon--tg { color: #29b6f6; }

.footer-contact-text {
  white-space: nowrap;
}

@media (max-width: 768px) {
  .footer { padding: 1.25rem; }
  .footer-inner { flex-direction: column; align-items: flex-start; }
  .footer-contacts { align-items: flex-start; }
  .footer-contacts-list { justify-content: flex-start; }
}

/* Typography / Prose */
.lead {
  font-size: 0.9375rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
  line-height: 1.5;
}

.prose {
  font-size: 0.875rem;
  line-height: 1.5;
  padding-left: 1.35rem;
}

.prose--compact {
  font-size: 0.8125rem;
  line-height: 1.48;
}

.prose h1 {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0 0 0.45rem;
  letter-spacing: -0.02em;
}
.prose h2 {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 1rem 0 0.35rem;
  padding-bottom: 0.22rem;
  border-bottom: 1px solid var(--border);
}
.prose h3 {
  font-size: 0.975rem;
  font-weight: 600;
  margin: 0.75rem 0 0.25rem;
}
.prose p { margin-bottom: 0.5rem; }
.prose ul, .prose ol { margin: 0 0 0.5rem 1.2rem; }
.prose li { margin-bottom: 0.12rem; }
.prose li > p { margin-bottom: 0.25rem; }

.prose .heading-anchor-wrap {
  position: relative;
  scroll-margin-top: calc(var(--topbar-h) + 0.75rem);
}

.prose .heading-anchor {
  position: absolute;
  left: -1.25rem;
  padding-right: 0.2rem;
  color: var(--accent-hover);
  opacity: 1;
  font-weight: 400;
  font-size: 0.9em;
  text-decoration: none;
  transition: color 0.12s;
  user-select: none;
}

.prose .heading-anchor:hover,
.prose .heading-anchor:focus {
  color: #93c5fd;
  text-decoration: none;
}

.prose .heading-anchor:focus-visible {
  outline: none;
  opacity: 1;
}

@media (max-width: 768px) {
  .prose { padding-left: 1.1rem; }
  .prose .heading-anchor {
    left: -1.1rem;
    opacity: 1;
  }
}

.prose blockquote {
  margin: 0.5rem 0;
  padding: 0.45rem 0.7rem;
  border-left: 3px solid var(--accent);
  background: var(--accent-glow);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--text-muted);
}
.prose blockquote strong { color: var(--text); }
.prose table {
  width: 100%;
  border-collapse: collapse;
  margin: 0.5rem 0;
  font-size: 0.8125rem;
}
.prose th, .prose td {
  padding: 0.35rem 0.5rem;
  border: 1px solid var(--border);
  text-align: left;
}
.prose th { background: var(--bg-elevated); font-weight: 600; }
.prose tr:hover td { background: var(--bg-hover); }
.prose code {
  font-family: var(--mono);
  font-size: 0.85em;
  background: var(--bg-elevated);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  border: 1px solid var(--border);
}
.prose pre {
  margin: 0.5rem 0;
  border-radius: var(--radius);
  overflow-x: auto;
  border: 1px solid var(--border);
}
.prose pre code { background: none; border: none; padding: 0; font-size: 0.8rem; }
.prose hr { border: none; border-top: 1px solid var(--border); margin: 0.85rem 0; }
.prose img { max-width: 100%; border-radius: var(--radius); border: 1px solid var(--border); }
.prose figure { margin: 0.6rem 0; }
.prose figcaption { margin-top: 0.35rem; font-size: 0.78rem; color: var(--text-muted); text-align: center; }

/* Home page */
.home-hero {
  position: relative;
  margin: -1.5rem -2rem 1.75rem;
  padding: 2rem 2rem 1.75rem;
  border-bottom: 1px solid var(--border);
  overflow: hidden;
}

.home-hero-glow {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 10% -10%, rgba(59, 130, 246, 0.18), transparent 55%),
    radial-gradient(ellipse 60% 50% at 90% 0%, rgba(96, 165, 250, 0.1), transparent 50%);
  pointer-events: none;
}

.home-hero-inner {
  position: relative;
  max-width: 640px;
}

.home-hero-label {
  display: inline-block;
  margin-bottom: 0.65rem;
  padding: 0.2rem 0.55rem;
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-hover);
  background: var(--accent-glow);
  border: 1px solid rgba(59, 130, 246, 0.25);
  border-radius: 999px;
}

.home-hero-title {
  font-size: 1.85rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 0.55rem;
}

.home-hero-lead {
  font-size: 0.9375rem;
  color: var(--text-muted);
  line-height: 1.5;
  margin-bottom: 0.75rem;
}

.home-hero-text {
  margin-top: 0.25rem;
  color: var(--text-muted);
}
.home-hero-text p:last-child { margin-bottom: 0; }

.home-sections {
  margin-bottom: 1.75rem;
}

.home-sections-head {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 1rem;
}

.home-sections-title {
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.home-sections-count {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 1.5rem;
  height: 1.5rem;
  padding: 0 0.4rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-hover);
  background: var(--accent-glow);
  border-radius: 999px;
}

.home-sections-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.75rem;
}

.home-section-card {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  padding: 1rem 1rem 0.85rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  text-decoration: none;
  transition: border-color 0.15s, transform 0.15s, box-shadow 0.15s;
}

.home-section-card:hover {
  border-color: rgba(96, 165, 250, 0.45);
  box-shadow: 0 6px 28px rgba(59, 130, 246, 0.12);
  transform: translateY(-2px);
  text-decoration: none;
}

.home-section-card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.home-section-card-num {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--accent-hover);
  font-family: var(--mono);
}

.home-section-card-arrow {
  color: var(--text-muted);
  font-size: 0.9rem;
  transition: transform 0.15s, color 0.15s;
}

.home-section-card:hover .home-section-card-arrow {
  transform: translateX(3px);
  color: var(--accent);
}

.home-section-card-title {
  font-size: 0.9375rem;
  font-weight: 600;
  line-height: 1.3;
}

.home-section-card-desc {
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.45;
  flex: 1;
}

.home-section-card-meta {
  margin-top: 0.15rem;
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--text-muted);
  opacity: 0.85;
}

.home-body {
  padding-top: 0.25rem;
  border-top: 1px solid var(--border);
}

@media (max-width: 768px) {
  .home-hero {
    margin: -1.25rem -1.25rem 1.25rem;
    padding: 1.25rem;
  }
  .home-hero-title { font-size: 1.5rem; }
  .home-sections-grid { grid-template-columns: 1fr; }
}

/* Section page */
.section-hero { margin-bottom: 2rem; }
.section-hero h1 { font-size: 2rem; font-weight: 700; letter-spacing: -0.02em; }

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem;
}

.card {
  position: relative;
  display: block;
  padding: 1.25rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  text-decoration: none;
  transition: border-color 0.15s, box-shadow 0.15s, transform 0.15s;
}
.card:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 24px var(--accent-glow);
  transform: translateY(-2px);
  text-decoration: none;
}
.card h3 { font-size: 1rem; font-weight: 600; margin-bottom: 0.4rem; }
.card p { font-size: 0.875rem; color: var(--text-muted); line-height: 1.5; }
.card-arrow {
  position: absolute;
  top: 1.25rem;
  right: 1.25rem;
  color: var(--text-muted);
  transition: transform 0.15s;
}
.card:hover .card-arrow { transform: translateX(3px); color: var(--accent); }

/* Search */
.search-page-form {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 2rem;
}
.search-page-form input {
  flex: 1;
  padding: 0.65rem 1rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-size: 1rem;
  outline: none;
}
.search-page-form input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-glow); }
.search-page-form button {
  padding: 0.65rem 1.25rem;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s;
}
.search-page-form button:hover { background: var(--accent-hover); }

.search-results { list-style: none; }
.search-results li { margin-bottom: 0.5rem; }
.search-results a {
  display: block;
  padding: 1rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  text-decoration: none;
  transition: border-color 0.15s;
}
.search-results a:hover { border-color: var(--accent); text-decoration: none; }
.search-results strong { display: block; margin-bottom: 0.25rem; }
.search-results p { font-size: 0.875rem; color: var(--text-muted); }
.search-results mark { background: var(--accent-glow); color: var(--accent-hover); border-radius: 2px; padding: 0 2px; }

.empty-state { color: var(--text-muted); text-align: center; padding: 2rem; }

/* 404 */
.error-page { text-align: center; padding: 4rem 1rem; }
.error-code { font-size: 5rem; font-weight: 700; color: var(--border); display: block; line-height: 1; }
.error-page h1 { margin: 1rem 0 0.5rem; }
.error-page p { color: var(--text-muted); margin-bottom: 1.5rem; }
.btn {
  display: inline-block;
  padding: 0.6rem 1.25rem;
  background: var(--accent);
  color: #fff;
  border-radius: var(--radius);
  font-weight: 500;
  text-decoration: none;
}
.btn:hover { background: var(--accent-hover); text-decoration: none; color: #fff; }

.overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: 90;
}

/* Mobile */
@media (max-width: 768px) {
  .sidebar { transform: translateX(-100%); transition: transform 0.25s ease; }
  .sidebar.open { transform: translateX(0); }
  .sidebar-close { display: block; }
  .menu-btn { display: flex; }
  .main { margin-left: 0; }
  .overlay.open { display: block; }
  .content { padding: 1.25rem; }
  .topbar { padding: 0 1rem; }
}