/* ── Design tokens ───────────────────────────────────────────────────────── */
:root {
  --bg-page:      #0d0d14;
  --bg-card:      #111118;
  --bg-sidebar:   #0a0a12;
  --bg-input:     #1a1a24;
  --border:       #2a2a38;
  --border-sub:   #1a1a22;
  --text:         #cccccc;
  --text-dim:     #888888;
  --text-faint:   #444444;
  --accent:       #4ec9b0;
  --accent-low:   rgba(78,201,176,.1);
  --accent-border:rgba(78,201,176,.3);
  --warn:         #f59e0b;
  --warn-low:     rgba(245,158,11,.1);
  --err:          #ef4444;
  --err-low:      rgba(239,68,68,.1);
  --conf-high:    #4ec9b0;
  --conf-med:     #f59e0b;
  --conf-low:     #ef4444;
  --topbar-h:     56px;
  --sidebar-w:    256px;
  --toc-w:        196px;
  --radius:       8px;
  --radius-sm:    4px;
  color-scheme: dark;
}
[data-theme="light"] {
  --bg-page:      #f4f4f8;
  --bg-card:      #ffffff;
  --bg-sidebar:   #f0f0f5;
  --bg-input:     #ededf2;
  --border:       #d4d4de;
  --border-sub:   #e4e4ec;
  --text:         #1a1a2a;
  --text-dim:     #555566;
  --text-faint:   #aaaabb;
  --accent:       #0a7c62;
  --accent-low:   rgba(10,124,98,.08);
  --accent-border:rgba(10,124,98,.28);
  --warn:         #b45309;
  --warn-low:     rgba(180,83,9,.08);
  --err:          #dc2626;
  --err-low:      rgba(220,38,38,.08);
  color-scheme: light;
}

/* ── Reset ───────────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans SC", sans-serif;
  background: var(--bg-page);
  color: var(--text);
  font-size: 14px;
  line-height: 1.7;
  min-height: 100vh;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; height: auto; display: block; }
ul, ol { padding-left: 1.5em; }
li { margin-bottom: .3em; }
p { margin-bottom: .9em; }
h1, h2, h3, h4 { line-height: 1.35; font-weight: 700; }
code { font-family: "Cascadia Code", "Fira Code", "Source Code Pro", monospace; }

/* ── Topbar ──────────────────────────────────────────────────────────────── */
.topbar {
  position: sticky; top: 0; z-index: 200;
  height: var(--topbar-h);
  background: var(--bg-sidebar);
  border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 12px;
  padding: 0 20px;
}
.topbar-left { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.hamburger {
  display: none; background: none; border: none;
  color: var(--text-dim); cursor: pointer; padding: 6px;
  border-radius: var(--radius-sm);
}
.hamburger:hover { background: var(--bg-input); }
.hamburger svg { display: block; }
.logo-link { display: flex; align-items: center; }
.logo-link img { height: 28px; width: auto; }
[data-theme="dark"]  .logo-light { display: none; }
[data-theme="dark"]  .logo-dark  { display: block; }
[data-theme="light"] .logo-dark  { display: none; }
[data-theme="light"] .logo-light { display: block; }
.topbar-nav { display: flex; align-items: center; gap: 4px; margin-left: 8px; }
.topbar-nav a {
  padding: 4px 10px; border-radius: var(--radius-sm);
  color: var(--text-dim); font-size: 13px;
  transition: color .15s, background .15s;
}
.topbar-nav a:hover { color: var(--text); background: var(--bg-input); text-decoration: none; }
.topbar-spacer { flex: 1; }
.topbar-controls { display: flex; align-items: center; gap: 6px; }
.icon-btn {
  background: none; border: 1px solid var(--border);
  border-radius: var(--radius-sm); color: var(--text-dim);
  cursor: pointer; padding: 5px 10px;
  font-size: 12px; font-weight: 600;
  display: flex; align-items: center; gap: 5px;
  transition: color .15s, border-color .15s, background .15s;
  white-space: nowrap;
}
.icon-btn:hover { color: var(--text); border-color: var(--accent-border); background: var(--accent-low); }
.icon-btn svg { flex-shrink: 0; }
[data-theme="dark"]  .icon-sun  { display: none; }
[data-theme="dark"]  .icon-moon { display: block; }
[data-theme="light"] .icon-moon { display: none; }
[data-theme="light"] .icon-sun  { display: block; }

/* ── Layout ──────────────────────────────────────────────────────────────── */
.layout {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr var(--toc-w);
  min-height: calc(100vh - var(--topbar-h));
}
.sidebar-overlay {
  display: none; position: fixed; inset: 0; z-index: 150;
  background: rgba(0,0,0,.5);
}
.sidebar-overlay.open { display: block; }

/* ── Sidebar ─────────────────────────────────────────────────────────────── */
.sidebar {
  position: sticky; top: var(--topbar-h);
  height: calc(100vh - var(--topbar-h));
  overflow-y: auto; overflow-x: hidden;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  padding: 16px 0;
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}
.sidebar::-webkit-scrollbar { width: 4px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }
.nav-group { margin-bottom: 4px; }
.nav-group-toggle {
  width: 100%; background: none; border: none;
  color: var(--text-faint); cursor: pointer;
  display: flex; align-items: center; justify-content: space-between;
  padding: 6px 20px; font-size: 11px; font-weight: 700;
  text-transform: uppercase; letter-spacing: .8px;
  transition: color .15s;
}
.nav-group-toggle:hover { color: var(--text-dim); }
.nav-group-toggle .chevron { transition: transform .2s; flex-shrink: 0; }
.nav-group-toggle[aria-expanded="false"] .chevron { transform: rotate(-90deg); }
.nav-group-items { overflow: hidden; transition: max-height .22s ease; }
.nav-link {
  display: block; padding: 5px 20px 5px 28px;
  color: var(--text-dim); font-size: 13px;
  border-left: 2px solid transparent;
  transition: color .15s, border-color .15s, background .15s;
}
.nav-link:hover { color: var(--text); background: var(--accent-low); text-decoration: none; }
.nav-link.active {
  color: var(--accent); border-left-color: var(--accent);
  background: var(--accent-low);
}

/* ── Main content ────────────────────────────────────────────────────────── */
.content {
  padding: 48px 52px;
  max-width: 820px;
  min-width: 0;
}
.doc-section {
  padding-bottom: 64px;
  border-bottom: 1px solid var(--border-sub);
  margin-bottom: 8px;
}
.doc-section:last-child { border-bottom: none; }
.section-eyebrow {
  font-size: 11px; font-weight: 700; text-transform: uppercase;
  letter-spacing: .8px; color: var(--accent); margin-bottom: 8px;
}
.doc-section h2 {
  font-size: 28px; font-weight: 800; margin-bottom: 16px;
  color: var(--text);
}
.doc-section h3 { font-size: 18px; margin: 28px 0 10px; color: var(--text); }
.doc-section h4 { font-size: 15px; margin: 20px 0 8px; color: var(--text-dim); }
.lead { font-size: 16px; color: var(--text-dim); margin-bottom: 20px; line-height: 1.65; }
.sec-body { color: var(--text); }
.sec-body p { margin-bottom: .85em; }
.sec-body ul, .sec-body ol { margin-bottom: .85em; }
.sec-body strong { color: var(--text); }
.sec-body em { color: var(--text-dim); }

/* ── Screenshot figure ───────────────────────────────────────────────────── */
.screenshot-fig {
  margin: 24px 0;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: 0 4px 24px rgba(0,0,0,.3);
}
.screenshot-fig img { width: 100%; }
.screenshot-fig figcaption {
  font-size: 11px; color: var(--text-faint);
  padding: 8px 14px;
  background: var(--bg-card);
  text-align: center;
}

/* ── Inline code & blocks ────────────────────────────────────────────────── */
.sec-body code, code.inline {
  background: var(--bg-input); color: var(--accent);
  padding: 2px 6px; border-radius: 3px;
  font-size: 13px;
}
.code-block {
  position: relative;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 52px 16px 18px;
  margin: 16px 0;
  overflow-x: auto;
}
.code-block code {
  background: none; color: var(--text);
  padding: 0; font-size: 13px;
  line-height: 1.6; white-space: pre;
}
.code-block[data-lang]::before {
  content: attr(data-lang);
  position: absolute; top: 8px; right: 48px;
  font-size: 10px; color: var(--text-faint);
  text-transform: uppercase; letter-spacing: .5px;
  font-family: -apple-system, sans-serif;
}
.copy-btn {
  position: absolute; top: 8px; right: 8px;
  background: none; border: 1px solid var(--border);
  border-radius: var(--radius-sm); color: var(--text-faint);
  cursor: pointer; padding: 3px 7px; font-size: 10px;
  transition: color .15s, border-color .15s;
}
.copy-btn:hover { color: var(--accent); border-color: var(--accent-border); }
.copy-btn.copied { color: var(--accent); border-color: var(--accent-border); }

/* ── Table ───────────────────────────────────────────────────────────────── */
.table-wrap { overflow-x: auto; margin: 16px 0; }
.doc-table {
  width: 100%; border-collapse: collapse;
  font-size: 13px;
}
.doc-table th {
  text-align: left; padding: 8px 14px;
  background: var(--bg-card);
  color: var(--text-dim); font-size: 11px; font-weight: 700;
  text-transform: uppercase; letter-spacing: .5px;
  border-bottom: 2px solid var(--border);
}
.doc-table td {
  padding: 9px 14px;
  border-bottom: 1px solid var(--border-sub);
  vertical-align: top;
}
.doc-table tr:last-child td { border-bottom: none; }
.doc-table tr:hover td { background: var(--accent-low); }

/* ── Keyboard badges ─────────────────────────────────────────────────────── */
kbd {
  display: inline-block;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-bottom-width: 2px;
  border-radius: 4px;
  padding: 2px 7px;
  font-family: inherit;
  font-size: 12px;
  color: var(--text);
  white-space: nowrap;
}
.kbd-sep { color: var(--text-faint); margin: 0 2px; font-size: 11px; }

/* ── Step list ───────────────────────────────────────────────────────────── */
.step-list { list-style: none; padding: 0; counter-reset: step; }
.step-item {
  display: flex; gap: 16px; margin-bottom: 20px; align-items: flex-start;
}
.step-num {
  flex-shrink: 0; width: 28px; height: 28px;
  background: var(--accent-low); border: 1px solid var(--accent-border);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 12px; font-weight: 700; color: var(--accent);
  margin-top: 2px;
}
.step-body { flex: 1; }
.step-body strong { display: block; font-size: 14px; margin-bottom: 4px; }

/* ── OS tabs ─────────────────────────────────────────────────────────────── */
.os-tabs { display: flex; gap: 0; border-bottom: 1px solid var(--border); margin-bottom: 0; }
.os-tab {
  background: none; border: none; border-bottom: 2px solid transparent;
  color: var(--text-dim); cursor: pointer;
  font-size: 13px; font-weight: 500; padding: 7px 16px;
  margin-bottom: -1px; transition: color .15s, border-color .15s;
}
.os-tab.active { color: var(--accent); border-bottom-color: var(--accent); }
.os-tab:hover { color: var(--text); }
.os-panel { display: none; }
.os-panel.active { display: block; }

/* ── Pipeline flow ───────────────────────────────────────────────────────── */
.pipeline-flow {
  display: flex; align-items: center; gap: 0;
  flex-wrap: wrap; margin: 24px 0; gap: 6px;
}
.pipeline-stage {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 10px 14px;
  display: flex; flex-direction: column; align-items: center; gap: 4px;
  min-width: 110px; text-align: center;
}
.pipeline-stage .stage-num {
  width: 22px; height: 22px; border-radius: 50%;
  background: var(--accent-low); border: 1px solid var(--accent-border);
  display: flex; align-items: center; justify-content: center;
  font-size: 11px; font-weight: 700; color: var(--accent);
}
.pipeline-stage .stage-label { font-size: 11px; color: var(--text-dim); font-weight: 600; }
.pipeline-arrow { color: var(--text-faint); font-size: 16px; }

/* ── Confidence grid ─────────────────────────────────────────────────────── */
.confidence-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin: 20px 0; }
.confidence-card {
  border-radius: var(--radius); border: 1px solid var(--border);
  padding: 14px 16px; border-left-width: 3px;
}
.confidence-card.high  { border-left-color: var(--conf-high); }
.confidence-card.med   { border-left-color: var(--conf-med);  }
.confidence-card.low   { border-left-color: var(--conf-low);  }
.conf-level { font-size: 11px; font-weight: 700; text-transform: uppercase; letter-spacing: .5px; }
.confidence-card.high  .conf-level { color: var(--conf-high); }
.confidence-card.med   .conf-level { color: var(--conf-med);  }
.confidence-card.low   .conf-level { color: var(--conf-low);  }
.conf-pct { font-size: 20px; font-weight: 800; display: block; margin: 4px 0; }
.confidence-card.high  .conf-pct { color: var(--conf-high); }
.confidence-card.med   .conf-pct { color: var(--conf-med);  }
.confidence-card.low   .conf-pct { color: var(--conf-low);  }
.conf-desc { font-size: 12px; color: var(--text-dim); margin: 0; }

/* ── Callout boxes ───────────────────────────────────────────────────────── */
.callout {
  border-radius: var(--radius); border: 1px solid;
  padding: 14px 16px; margin: 16px 0;
  display: flex; gap: 10px; align-items: flex-start;
}
.callout-icon { font-size: 16px; flex-shrink: 0; margin-top: 1px; }
.callout-body { flex: 1; font-size: 13px; }
.callout-body p { margin-bottom: .4em; }
.callout-body p:last-child { margin-bottom: 0; }
.callout-info  { border-color: rgba(59,130,246,.3); background: rgba(59,130,246,.06); }
.callout-info  .callout-icon { color: #60a5fa; }
.callout-warn  { border-color: rgba(245,158,11,.3); background: var(--warn-low); }
.callout-warn  .callout-icon { color: var(--warn); }
.callout-tip   { border-color: var(--accent-border); background: var(--accent-low); }
.callout-tip   .callout-icon { color: var(--accent); }
.callout-err   { border-color: rgba(239,68,68,.3); background: var(--err-low); }
.callout-err   .callout-icon { color: var(--err); }

/* ── Ghost node callout ──────────────────────────────────────────────────── */
.ghost-node-badge {
  display: inline-flex; align-items: center; justify-content: center;
  width: 18px; height: 18px; border-radius: 50%;
  border: 2px solid var(--err); color: var(--err);
  font-size: 9px; font-weight: 700; margin-right: 4px;
  vertical-align: middle;
}

/* ── FAQ accordion ───────────────────────────────────────────────────────── */
.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius); margin-bottom: 8px;
  overflow: hidden;
}
.faq-item summary {
  list-style: none; padding: 14px 18px;
  cursor: pointer; font-size: 14px; font-weight: 600;
  color: var(--text); display: flex; align-items: center;
  justify-content: space-between; gap: 12px;
  transition: background .15s;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary:hover { background: var(--accent-low); }
.faq-item[open] summary { color: var(--accent); }
.faq-chevron { transition: transform .2s; flex-shrink: 0; color: var(--text-faint); }
.faq-item[open] .faq-chevron { transform: rotate(90deg); }
.faq-body { padding: 4px 18px 16px; font-size: 13px; color: var(--text-dim); line-height: 1.65; }
.faq-body p { margin-bottom: .6em; }
.faq-body p:last-child { margin-bottom: 0; }
.faq-body code { background: var(--bg-input); color: var(--accent); padding: 2px 5px; border-radius: 3px; }

/* ── Contact form ────────────────────────────────────────────────────────── */
.contact-form { max-width: 480px; }
.form-group { margin-bottom: 16px; }
.form-label { display: block; font-size: 12px; font-weight: 600; color: var(--text-dim); margin-bottom: 6px; }
.form-input, .form-textarea {
  width: 100%; background: var(--bg-card);
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  color: var(--text); padding: 9px 12px;
  font-size: 13px; font-family: inherit; outline: none;
  transition: border-color .15s;
}
.form-input:focus, .form-textarea:focus { border-color: var(--accent-border); }
.form-textarea { min-height: 120px; resize: vertical; }
.form-submit {
  background: var(--accent-low); border: 1px solid var(--accent-border);
  border-radius: var(--radius-sm); color: var(--accent);
  cursor: pointer; font-size: 13px; font-weight: 700;
  padding: 9px 24px; transition: background .15s;
}
.form-submit:hover { background: rgba(78,201,176,.2); }
.form-submit:disabled { opacity: .5; cursor: not-allowed; }
.form-status { margin-top: 10px; font-size: 12px; }
.form-status.ok  {
  color: var(--accent); font-size: 14px; font-weight: 600;
  background: rgba(78,201,176,.08); border: 1px solid rgba(78,201,176,.3);
  border-radius: var(--radius); padding: 12px 16px; margin-top: 14px;
  display: block;
}
.form-status.err { color: var(--err); }
#turnstile-widget { margin: 12px 0; }
.wechat-hint {
  margin-top: 20px; padding: 12px 14px;
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); font-size: 13px; color: var(--text-dim);
}
.wechat-hint strong { color: var(--text); }

/* ── Right-rail TOC ──────────────────────────────────────────────────────── */
.toc-rail {
  position: sticky; top: var(--topbar-h);
  height: calc(100vh - var(--topbar-h));
  overflow-y: auto; padding: 32px 16px;
}
.toc-title { font-size: 11px; font-weight: 700; text-transform: uppercase; letter-spacing: .7px; color: var(--text-faint); margin-bottom: 10px; }
.toc-list { list-style: none; padding: 0; }
.toc-item { margin-bottom: 2px; }
.toc-item.toc-sub .toc-link { padding-left: 16px; font-size: 12px; }
.toc-link {
  display: block; color: var(--text-faint); font-size: 12.5px;
  padding: 3px 6px; border-radius: 3px;
  transition: color .15s, background .15s;
  border-left: 2px solid transparent;
}
.toc-link:hover { color: var(--text-dim); text-decoration: none; background: var(--accent-low); }
.toc-link.active { color: var(--accent); border-left-color: var(--accent); background: var(--accent-low); }

/* ── Footer ──────────────────────────────────────────────────────────────── */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 28px 40px;
  background: var(--bg-sidebar);
}
.footer-inner {
  max-width: 900px; margin: 0 auto;
  display: flex; align-items: center; gap: 20px; flex-wrap: wrap;
}
.footer-brand { display: flex; flex-direction: column; gap: 2px; }
.footer-name { font-size: 13px; font-weight: 700; color: var(--text); }
.footer-by { font-size: 11px; color: var(--text-faint); }
.footer-links { display: flex; gap: 16px; flex-wrap: wrap; margin-left: auto; }
.footer-links a { font-size: 12px; color: var(--text-dim); }
.footer-links a:hover { color: var(--accent); }
.footer-copy { font-size: 11px; color: var(--text-faint); white-space: nowrap; }

/* ── Sec-body markdown rendering ─────────────────────────────────────────── */
.sec-body h3 { font-size: 17px; margin: 28px 0 10px; }
.sec-body h4 { font-size: 14px; margin: 18px 0 6px; color: var(--text-dim); }
.sec-body blockquote {
  border-left: 3px solid var(--accent-border);
  padding: 8px 16px; margin: 12px 0;
  color: var(--text-dim); background: var(--accent-low);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.sec-body table { width: 100%; border-collapse: collapse; margin: 12px 0; font-size: 13px; }
.sec-body th { text-align: left; padding: 8px 12px; background: var(--bg-card); border-bottom: 2px solid var(--border); color: var(--text-dim); font-size: 11px; font-weight: 700; text-transform: uppercase; }
.sec-body td { padding: 8px 12px; border-bottom: 1px solid var(--border-sub); }
.sec-body hr { border: none; border-top: 1px solid var(--border-sub); margin: 24px 0; }
.sec-body pre { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 16px; margin: 12px 0; overflow-x: auto; }
.sec-body pre code { background: none; color: var(--text); padding: 0; font-size: 13px; }

/* ── Responsive ──────────────────────────────────────────────────────────── */
@media (max-width: 1200px) {
  .toc-rail { display: none; }
  .layout { grid-template-columns: var(--sidebar-w) 1fr; }
}
@media (max-width: 768px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar {
    position: fixed; top: var(--topbar-h); left: 0; bottom: 0; z-index: 160;
    transform: translateX(-100%); transition: transform .25s ease;
    width: var(--sidebar-w); height: auto;
  }
  .sidebar.open { transform: translateX(0); }
  .sidebar-overlay { display: none; }
  .sidebar-overlay.open { display: block; }
  .hamburger { display: flex; }
  .topbar-nav { display: none; }
  .content { padding: 28px 20px; }
  .confidence-grid { grid-template-columns: 1fr; }
  .pipeline-flow { flex-direction: column; }
  .pipeline-arrow { transform: rotate(90deg); }
}
@media (max-width: 480px) {
  .doc-section h2 { font-size: 22px; }
}