:root{
  --bg:#f7f9fb;
  --surface:#ffffff;
  --surface2:#f1f5f9;
  --surface3:#e2e8f0;
  --text:#0f172a;
  --dim:#475569;
  --faint:#94a3b8;
  --accent:#2563eb;
  --accent2:#3b82f6;
  --border:#e2e8f0;
  --shadow:0 1px 3px 0 rgba(15,23,42,.04),0 1px 2px -1px rgba(15,23,42,.04);
  --shadow-lg:0 10px 25px -5px rgba(15,23,42,.06),0 4px 10px -2px rgba(15,23,42,.04);
  --mono:ui-monospace,"JetBrains Mono","SF Mono",Menlo,Consolas,monospace;
  --sans:-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:var(--sans);color:var(--text);background:var(--bg);line-height:1.75;font-size:15.5px;min-height:100vh}
a{color:var(--accent2);text-decoration:none;transition:color .15s}
a:hover{color:var(--accent);text-decoration:underline}

/* topbar */
.topbar{position:sticky;top:0;z-index:40;display:flex;align-items:center;justify-content:space-between;
  padding:0 32px;height:60px;background:rgba(247,249,251,.92);backdrop-filter:blur(12px);border-bottom:1px solid var(--border);box-shadow:var(--shadow)}
.brand{display:flex;align-items:center;gap:10px;color:var(--text);font-weight:700;font-size:15px;letter-spacing:-.2px}
.brand .logo{width:22px;height:22px;color:var(--accent)}
.brand:hover{text-decoration:none;color:var(--text)}
.topbar-right{display:flex;align-items:center;gap:12px}
.toggle-side{background:var(--surface);border:1px solid var(--border);color:var(--text);border-radius:8px;padding:7px 12px;cursor:pointer;font-size:13px;font-weight:500;transition:.15s}
.toggle-side:hover{border-color:var(--accent);color:var(--accent);background:var(--surface2)}
.toggle-side:focus-visible{outline:2px solid var(--accent);outline-offset:2px}

/* layout: left nav | middle toc | right content (extreme compact left, content fills rest) */
.layout{display:grid;grid-template-columns:200px 220px minmax(0,1fr);gap:12px;padding:28px 20px 60px;align-items:start}
.sidebar{position:sticky;top:88px;height:calc(100vh - 112px);overflow-y:auto;width:200px;
  background:var(--surface);border:1px solid var(--border);border-radius:16px;padding:12px;box-shadow:var(--shadow)}
.side-sec{font-size:11px;font-weight:700;letter-spacing:.8px;color:var(--faint);text-transform:uppercase;margin-bottom:14px;padding-left:6px}
.doc-nav{display:flex;flex-direction:column;gap:4px}
.doc-link{display:flex;align-items:center;gap:8px;padding:8px 9px;border-radius:8px;color:var(--dim);font-size:13px;line-height:1.4;transition:.15s;overflow:hidden}
.doc-link:hover{background:var(--surface2);color:var(--text);text-decoration:none}
.doc-name{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.doc-link.active{background:rgba(37,99,235,.08);color:var(--accent);box-shadow:inset 3px 0 0 0 var(--accent)}
.doc-ix{font-family:var(--mono);font-size:11px;color:var(--faint);min-width:26px;text-align:center}
.doc-link.active .doc-ix{color:var(--accent);font-weight:700}

.sidebar-backdrop{display:none}

.page-toc{position:sticky;top:88px;height:calc(100vh - 112px);overflow-y:auto;width:220px;
  background:var(--surface);border:1px solid var(--border);border-radius:16px;padding:12px;box-shadow:var(--shadow);font-size:13.5px}
.toc-title{font-size:11px;font-weight:700;letter-spacing:.8px;color:var(--faint);text-transform:uppercase;margin-bottom:14px}
.page-toc .toc-list{list-style:none}
.page-toc .toc-list li{margin:4px 0}
.page-toc .lvl-2 a{color:var(--text);display:block;padding:5px 8px;border-radius:6px;line-height:1.5}
.page-toc .lvl-3 a{color:var(--dim);display:block;padding:4px 8px 4px 18px;border-radius:6px;line-height:1.45;font-size:12.5px}
.page-toc a:hover{color:var(--text);background:var(--surface2);text-decoration:none}
.page-toc a.active{color:var(--accent);background:rgba(37,99,235,.08);font-weight:600}
.toc-empty{color:var(--faint);font-size:12.5px}

.content{min-width:0;padding:4px 0 80px}
.page-title{font-size:32px;font-weight:800;letter-spacing:-.6px;margin-bottom:12px;line-height:1.25;color:var(--text)}
.page-desc{color:var(--dim);font-size:15px;margin-bottom:32px;padding-bottom:22px;border-bottom:1px solid var(--border);line-height:1.65}

/* markdown content */
.content h2{font-size:24px;font-weight:700;margin:42px 0 16px;padding-top:10px;color:var(--text);scroll-margin-top:92px;border-bottom:1px solid var(--border);padding-bottom:10px}
.content h3{font-size:19px;font-weight:700;margin:30px 0 12px;color:#1e293b;scroll-margin-top:92px}
.content h4{font-size:16px;font-weight:700;margin:20px 0 10px;color:var(--dim)}
.content p{margin:14px 0;color:var(--text)}
.content ul,.content ol{margin:14px 0;padding-left:28px}
.content li{margin:7px 0}
.content blockquote{border-left:3px solid var(--accent);background:var(--surface2);padding:12px 18px;margin:18px 0;border-radius:0 10px 10px 0;color:var(--dim)}
.content code{font-family:var(--mono);font-size:13.5px;background:var(--surface2);padding:2px 6px;border-radius:5px;color:#1d4ed8}
.content pre{background:#fff;border:1px solid var(--border);border-radius:12px;padding:18px 20px;overflow-x:auto;margin:18px 0;box-shadow:inset 0 1px 2px rgba(15,23,42,.04)}
.content pre code{background:none;padding:0;color:#334155;font-size:13px;line-height:1.65}
.content table{border-collapse:separate;border-spacing:0;width:100%;margin:20px 0;font-size:13.5px;border:1px solid var(--border);border-radius:10px;overflow:hidden;background:var(--surface)}
.content th,.content td{border-bottom:1px solid var(--border);padding:10px 14px;text-align:left;vertical-align:top}
.content th{background:var(--surface2);color:var(--text);font-weight:700}
.content tr:last-child td{border-bottom:none}
.content tr:nth-child(even) td{background:rgba(241,245,249,.5)}
.content img{max-width:100%;border-radius:10px;margin:16px 0;border:1px solid var(--border)}
.content hr{border:none;border-top:1px solid var(--border);margin:36px 0}
.content details{border:1px solid var(--border);border-radius:10px;padding:12px 16px;margin:16px 0;background:var(--surface)}
.content summary{cursor:pointer;font-weight:600;color:var(--accent2);list-style-position:outside}
.content a{word-break:break-word}
.content strong{color:#0f172a;font-weight:700}

/* responsive */
@media (max-width:1300px){
  .layout{grid-template-columns:260px 1fr;gap:28px}
  .page-toc{display:none}
  .content{max-width:none}
}
@media (max-width:900px){
  .layout{grid-template-columns:1fr;padding:20px 18px 60px}
  .sidebar{position:fixed;top:60px;left:-300px;z-index:35;width:280px;height:calc(100vh - 60px);transition:left .25s ease;background:var(--surface);border:1px solid var(--border);border-radius:0 16px 16px 0;box-shadow:4px 0 20px rgba(15,23,42,.12)}
  .sidebar.open{left:0}
  .sidebar-backdrop{display:block;position:fixed;inset:0;background:rgba(15,23,42,.15);z-index:34;opacity:0;pointer-events:none;transition:opacity .25s}
  .sidebar-backdrop.show{opacity:1;pointer-events:auto}
  .content{padding:4px 0 70px}
  .page-title{font-size:26px}
}
@media (max-width:560px){
  .topbar{padding:0 16px}
  .content{padding:4px 0 60px}
  .page-title{font-size:24px}
  .content h2{font-size:20px}
}

/* portal */
.portal{background:radial-gradient(1000px 600px at 80% -10%,rgba(59,130,246,.10),transparent 55%),var(--bg)}
.portal-hero{padding:72px 20px 48px;text-align:center;border-bottom:1px solid var(--border)}
.hero-inner{max-width:760px;margin:0 auto}
.hero-logo{width:56px;height:56px;color:var(--accent);margin:0 auto 18px}
.portal-hero h1{font-size:38px;font-weight:800;letter-spacing:-.6px;color:var(--text)}
.hero-sub{color:var(--dim);margin:14px 0 30px;font-size:16px}
.kb-search{width:min(480px,92%);padding:13px 18px;border-radius:14px;border:1px solid var(--border);
  background:var(--surface);color:var(--text);font-size:15px;font-family:var(--sans);transition:.15s}
.kb-search:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 4px rgba(37,99,235,.12)}
.portal-grid{max-width:1120px;margin:0 auto;padding:44px 24px;display:grid;gap:16px;
  grid-template-columns:repeat(auto-fill,minmax(300px,1fr))}
.card{display:flex;align-items:flex-start;gap:14px;padding:20px;border:1px solid var(--border);border-radius:14px;
  background:var(--surface);transition:.2s}
.card:hover{border-color:var(--accent);background:var(--surface);text-decoration:none;transform:translateY(-2px);box-shadow:var(--shadow-lg)}
.card-ix{font-family:var(--mono);font-size:13px;color:var(--accent);background:rgba(37,99,235,.08);
  border-radius:8px;padding:8px 10px;min-width:42px;text-align:center;font-weight:700;flex-shrink:0}
.card-body{flex:1;min-width:0}
.card-title{font-weight:700;color:var(--text);font-size:15px;margin-bottom:6px;line-height:1.4}
.card-desc{color:var(--dim);font-size:13px;line-height:1.55;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.card-go{color:var(--faint);font-size:18px;margin-left:4px;transition:.15s}
.card:hover .card-go{color:var(--accent);transform:translateX(3px)}
.card.hidden{display:none}
.portal-foot{text-align:center;color:var(--faint);font-size:12.5px;padding:34px 20px 60px}