:root{
  --bg:#1a1d23; --card:#2a2d35; --text:#f1f3f5; --muted:#adb5bd;
  --brand:#4c6ef5; --accent:#20c997; --border:#3c4043; --radius:10px;
  --sidebar-w:280px; --header-h:60px; --max:820px;
}
*{box-sizing:border-box}
html{scroll-padding-top:calc(var(--header-h) + 16px)}
body{margin:0;background:var(--bg);color:var(--text);
  font-family:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;
  line-height:1.65;-webkit-font-smoothing:antialiased}
a{color:var(--brand);text-decoration:none}
a:hover{text-decoration:underline}

/* Header */
.dh{position:sticky;top:0;z-index:50;height:var(--header-h);
  background:rgba(26,29,35,.95);backdrop-filter:blur(10px);border-bottom:1px solid var(--border)}
.dh-wrap{display:flex;align-items:center;gap:20px;height:100%;padding:0 24px}
.dh-brand{display:flex;align-items:center;gap:10px;font-weight:700;color:var(--text)}
.dh-brand:hover{text-decoration:none}
.dh-logo{color:var(--accent);font-size:18px}
.dh-nav{margin-left:auto}
.dh-nav a{color:var(--muted);font-size:14px}
.dh-toggle{display:none;background:none;border:none;color:var(--text);font-size:22px;cursor:pointer}

/* Layout */
.layout{display:flex;align-items:flex-start;max-width:1400px;margin:0 auto}
.sidebar{position:sticky;top:var(--header-h);align-self:flex-start;
  width:var(--sidebar-w);flex:0 0 var(--sidebar-w);
  height:calc(100vh - var(--header-h));overflow-y:auto;
  padding:28px 18px;border-right:1px solid var(--border)}
.side-nav{display:flex;flex-direction:column;gap:2px}
.side-link{padding:7px 12px;border-radius:8px;color:var(--muted);font-size:14.5px;font-weight:500}
.side-link:hover{background:var(--card);color:var(--text);text-decoration:none}
.side-link.active{background:rgba(76,110,245,.15);color:var(--brand)}

/* Content */
.doc{flex:1 1 auto;min-width:0;display:flex;gap:32px;padding:40px 40px 80px;justify-content:center}
.doc-content{max-width:var(--max);width:100%;min-width:0}
.doc-content h1{font-size:36px;line-height:1.2;margin:0 0 24px}
.doc-content h2{font-size:26px;margin:44px 0 14px;padding-top:6px;border-top:1px solid var(--border)}
.doc-content h3{font-size:20px;margin:30px 0 10px}
.doc-content h4{font-size:16px;margin:22px 0 8px}
.doc-content p{margin:0 0 16px}
.doc-content ul,.doc-content ol{margin:0 0 16px;padding-left:24px}
.doc-content li{margin:6px 0}
.doc-content img{max-width:100%;height:auto;border-radius:8px}
.doc-content hr{border:none;border-top:1px solid var(--border);margin:36px 0}
.doc-content blockquote{margin:0 0 16px;padding:2px 18px;border-left:3px solid var(--accent);
  color:var(--muted);background:rgba(32,201,151,.06);border-radius:0 8px 8px 0}
.doc-content code{font-family:"SF Mono",ui-monospace,Menlo,Consolas,monospace;font-size:.88em;
  background:var(--card);padding:2px 6px;border-radius:5px}
.doc-content pre{background:#12141a;border:1px solid var(--border);border-radius:var(--radius);
  padding:16px 18px;overflow-x:auto;margin:0 0 18px}
.doc-content pre code{background:none;padding:0;font-size:13.5px;line-height:1.55}
.doc-content table{width:100%;border-collapse:collapse;margin:0 0 18px;display:block;overflow-x:auto}
.doc-content th,.doc-content td{border:1px solid var(--border);padding:8px 12px;text-align:left}
.doc-content th{background:var(--card)}
.doc-content a{border-bottom:1px solid rgba(76,110,245,.35)}
.doc-content a:hover{text-decoration:none;border-bottom-color:var(--brand)}

.page-index{list-style:none;padding:0}
.page-index li{margin:10px 0;color:var(--muted)}

/* Prev / next */
.prevnext{display:flex;justify-content:space-between;gap:16px;margin-top:48px;
  padding-top:20px;border-top:1px solid var(--border)}
.pn{padding:12px 16px;border:1px solid var(--border);border-radius:var(--radius);
  background:var(--card);color:var(--text);font-weight:600;font-size:14px}
.pn:hover{border-color:var(--brand);text-decoration:none}
.pn.next{margin-left:auto;text-align:right}

/* TOC */
.toc{position:sticky;top:calc(var(--header-h) + 24px);align-self:flex-start;
  width:200px;flex:0 0 200px;font-size:13.5px;max-height:calc(100vh - var(--header-h) - 48px);overflow-y:auto}
.toc nav>ul{list-style:none;margin:0;padding:0;border-left:1px solid var(--border)}
.toc ul ul{list-style:none;padding-left:14px}
.toc li{margin:6px 0}
.toc a{color:var(--muted)}
.toc a:hover{color:var(--text);text-decoration:none}

@media (max-width:1100px){ .toc{display:none} }
@media (max-width:820px){
  .dh-toggle{display:block}
  .sidebar{position:fixed;top:var(--header-h);left:0;z-index:40;background:var(--bg);
    transform:translateX(-100%);transition:transform .2s ease;width:82%;max-width:320px}
  body.nav-open .sidebar{transform:none}
  .doc{padding:28px 20px 64px}
  .doc-content h1{font-size:30px}
}