:root {
  color-scheme: light dark;
  --bg: #eef2f5;
  --paper: #ffffff;
  --paper-raised: #f8fafc;
  --ink: #18202b;
  --muted: #667487;
  --line: #d6dee8;
  --line-strong: #b7c4d4;
  --accent: #0f766e;
  --accent-ink: #0b4f4a;
  --accent-soft: #dff4ef;
  --blue: #2457a6;
  --blue-soft: #e8f0ff;
  --amber: #9a5b00;
  --amber-soft: #fff3d6;
  --danger: #a13d38;
  --danger-soft: #ffe7e5;
  --security: #46611d;
  --security-soft: #edf7d7;
  --code-bg: #0d1321;
  --code-ink: #e9eef8;
  --shadow: 0 12px 30px rgba(15, 23, 42, 0.08);
  --sidebar-width: 322px;
  --radius: 8px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #10151c;
    --paper: #161d27;
    --paper-raised: #1d2633;
    --ink: #e7edf5;
    --muted: #a4b1c3;
    --line: #303b4c;
    --line-strong: #465267;
    --accent: #4fc1b4;
    --accent-ink: #b9fff4;
    --accent-soft: #133a38;
    --blue: #8fb4ff;
    --blue-soft: #152a4d;
    --amber: #f3bf67;
    --amber-soft: #3d2c12;
    --danger: #ff9b96;
    --danger-soft: #45201f;
    --security: #bbdc76;
    --security-soft: #293817;
    --code-bg: #070b12;
    --code-ink: #edf4ff;
    --shadow: 0 16px 34px rgba(0, 0, 0, 0.28);
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
  line-height: 1.62;
}
a { color: var(--accent); text-underline-offset: 3px; }
a:hover { color: var(--blue); }
a:focus-visible,
button:focus-visible,
input:focus-visible {
  outline: 3px solid var(--blue);
  outline-offset: 2px;
}
.layout {
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  min-height: 100vh;
}
.mobile-bar { display: none; }
.sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: auto;
  padding: 22px 18px 28px;
  background: var(--paper);
  border-right: 1px solid var(--line);
}
.brand { margin-bottom: 20px; }
.brand a {
  display: block;
  color: var(--ink);
  font-size: 21px;
  font-weight: 800;
  line-height: 1.2;
  text-decoration: none;
}
.brand span {
  display: block;
  margin-top: 5px;
  color: var(--muted);
  font-size: 12px;
}
.search-label {
  display: block;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  margin: 0 0 6px;
  text-transform: uppercase;
}
.chapter-search {
  width: 100%;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--paper-raised);
  color: var(--ink);
  font: inherit;
  font-size: 14px;
  padding: 10px 11px;
  margin-bottom: 14px;
}
.sidebar-nav { padding-bottom: 20px; }
.nav-group {
  border-top: 1px solid var(--line);
  padding: 8px 0;
}
.nav-group summary {
  cursor: pointer;
  color: var(--accent-ink);
  font-size: 13px;
  font-weight: 800;
  line-height: 1.35;
  list-style-position: outside;
  text-transform: uppercase;
}
.nav-group ol {
  list-style: none;
  margin: 8px 0 0;
  padding: 0;
}
.nav-link {
  display: block;
  color: var(--ink);
  border-radius: 6px;
  padding: 7px 9px;
  text-decoration: none;
  font-size: 14px;
  line-height: 1.3;
}
.nav-link:hover {
  background: var(--accent-soft);
  color: var(--accent-ink);
}
.nav-link.active {
  background: var(--blue-soft);
  color: var(--blue);
  font-weight: 700;
}
.nav-hidden { display: none; }
.content {
  min-width: 0;
  padding: 34px 30px 70px;
}
.page-shell {
  max-width: 980px;
  margin: 0 auto;
}
.page-head {
  margin: 0 0 22px;
  padding: 28px 30px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.kicker {
  color: var(--accent);
  font-size: 13px;
  font-weight: 800;
  margin-bottom: 8px;
  text-transform: uppercase;
}
.page-head h1 {
  margin: 0;
  font-size: 34px;
  line-height: 1.18;
}
.page-head p {
  max-width: 760px;
  margin: 10px 0 0;
  color: var(--muted);
}
.chapter-body,
.toc-grid,
.guide-summary,
.callout,
.chapter-switch {
  max-width: 940px;
}
.chapter-body {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px;
}
h1, h2, h3, h4, h5, h6 {
  color: var(--ink);
  letter-spacing: 0;
  line-height: 1.25;
}
.chapter-body > h1:first-child { margin-top: 0; }
h1 { font-size: 32px; margin: 0 0 18px; }
h2 {
  margin: 34px 0 12px;
  padding-bottom: 7px;
  border-bottom: 1px solid var(--line);
  font-size: 24px;
}
h3 { margin: 26px 0 10px; font-size: 20px; }
h4 { margin: 22px 0 8px; font-size: 17px; }
p, ul, ol { margin: 0 0 15px; }
li { margin: 5px 0; }
code {
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: 5px;
  color: var(--blue);
  font-family: Consolas, "Courier New", monospace;
  font-size: 0.92em;
  padding: 1px 5px;
}
.code-block {
  margin: 18px 0;
  overflow: hidden;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--code-bg);
}
.code-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: 36px;
  padding: 7px 10px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
  color: #9fb0c7;
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
}
.code-toolbar button {
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.08);
  color: #dbe7ff;
  cursor: pointer;
  font: inherit;
  padding: 4px 8px;
  text-transform: none;
}
pre {
  margin: 0;
  overflow-x: auto;
  padding: 16px;
  color: var(--code-ink);
}
pre code {
  background: transparent;
  border: 0;
  color: inherit;
  padding: 0;
  white-space: pre;
}
.table-wrap {
  overflow-x: auto;
  margin: 18px 0 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
table {
  width: 100%;
  min-width: 680px;
  border-collapse: collapse;
  background: var(--paper);
}
th, td {
  border-bottom: 1px solid var(--line);
  padding: 10px 12px;
  text-align: left;
  vertical-align: top;
}
th {
  background: var(--paper-raised);
  color: var(--ink);
  font-weight: 800;
}
tr:last-child td { border-bottom: 0; }
.media {
  margin: 22px 0;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper-raised);
}
.media img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 0 auto;
  border-radius: 5px;
}
.media figcaption {
  margin-top: 9px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.4;
  text-align: center;
}
.callout {
  margin: 18px 0;
  padding: 15px 16px;
  border: 1px solid var(--line);
  border-left-width: 5px;
  border-radius: var(--radius);
  background: var(--paper-raised);
}
.callout-title {
  margin-bottom: 4px;
  font-size: 13px;
  font-weight: 800;
  text-transform: uppercase;
}
.callout p:last-child { margin-bottom: 0; }
.callout-note { border-left-color: var(--blue); background: var(--blue-soft); }
.callout-warning { border-left-color: var(--amber); background: var(--amber-soft); }
.callout-security { border-left-color: var(--security); background: var(--security-soft); }
.callout-production { border-left-color: var(--accent); background: var(--accent-soft); }
blockquote {
  margin: 18px 0;
  padding: 12px 16px;
  border-left: 4px solid var(--line-strong);
  background: var(--paper-raised);
  color: var(--muted);
}
.checklist {
  list-style: none;
  padding-left: 0;
}
.checklist li {
  display: flex;
  gap: 8px;
  align-items: flex-start;
}
.checked, .unchecked {
  flex: 0 0 auto;
  width: 18px;
  height: 18px;
  margin-top: 4px;
  border: 1px solid var(--accent);
  border-radius: 4px;
  color: var(--accent);
  font-size: 13px;
  line-height: 16px;
  text-align: center;
}
.unchecked { border-color: var(--line-strong); }
.guide-summary {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin: 0 0 18px;
}
.guide-summary div,
.toc-section {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
}
.guide-summary strong {
  display: block;
  font-size: 24px;
  line-height: 1.1;
}
.guide-summary span {
  color: var(--muted);
  font-size: 13px;
}
.toc-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-top: 18px;
}
.toc-section h2 {
  margin-top: 0;
  font-size: 19px;
}
.toc-section ol {
  margin-bottom: 0;
  padding-left: 22px;
}
.chapter-switch {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-top: 20px;
}
.chapter-switch a,
.chapter-switch > span {
  min-height: 82px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper);
  color: var(--ink);
  text-decoration: none;
}
.chapter-switch span span,
.chapter-switch a span {
  display: block;
  margin-bottom: 4px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
  text-transform: uppercase;
}
.chapter-next { text-align: right; }

@media (max-width: 980px) {
  .mobile-bar {
    position: sticky;
    top: 0;
    z-index: 20;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 10px 14px;
    border-bottom: 1px solid var(--line);
    background: var(--paper);
  }
  .mobile-brand {
    color: var(--ink);
    font-weight: 800;
    text-decoration: none;
  }
  .nav-toggle {
    border: 1px solid var(--line-strong);
    border-radius: 6px;
    background: var(--paper-raised);
    color: var(--ink);
    cursor: pointer;
    font: inherit;
    padding: 6px 10px;
  }
  .layout { display: block; }
  .sidebar {
    position: fixed;
    z-index: 30;
    left: 0;
    top: 0;
    width: min(88vw, 340px);
    transform: translateX(-105%);
    visibility: hidden;
    pointer-events: none;
    transition: transform 160ms ease;
    box-shadow: var(--shadow);
  }
  body.nav-open .sidebar {
    transform: translateX(0);
    visibility: visible;
    pointer-events: auto;
  }
  .content { padding: 22px 14px 56px; }
  .page-head,
  .chapter-body { padding: 22px; }
  .page-head h1 { font-size: 28px; }
  .guide-summary,
  .toc-grid,
  .chapter-switch { grid-template-columns: 1fr; }
  .chapter-next { text-align: left; }
}

@media print {
  :root {
    --bg: #ffffff;
    --paper: #ffffff;
    --paper-raised: #ffffff;
    --ink: #111827;
    --muted: #4b5563;
    --line: #cbd5e1;
  }
  body { background: #ffffff; font-size: 11pt; }
  .mobile-bar,
  .sidebar,
  .chapter-switch,
  .code-toolbar { display: none !important; }
  .layout { display: block; }
  .content { padding: 0; }
  .page-shell { max-width: none; }
  .page-head,
  .chapter-body,
  .toc-section,
  .guide-summary div {
    border: 0;
    box-shadow: none;
    padding-left: 0;
    padding-right: 0;
  }
  .chapter-body {
    break-inside: auto;
    page-break-inside: auto;
  }
  h1, h2, h3 { break-after: avoid; page-break-after: avoid; }
  .media,
  .table-wrap,
  .code-block,
  .callout {
    break-inside: avoid;
    page-break-inside: avoid;
  }
  a { color: #111827; text-decoration: none; }
}