:root{
  --brand:#4B3BF1;
  --brand-tint:#eeebff;
  --ink:#0E0E12;
  --ink-2:#3a3a44;
  --ink-3:#6a6a76;
  --line:#e5e3df;
  --paper:#ffffff;
  --sand:#f6f3ec;
  --shadow-sm:0 1px 2px rgba(15,15,20,.04), 0 1px 1px rgba(15,15,20,.03);
  --shadow-md:0 6px 24px rgba(15,15,20,.06), 0 2px 6px rgba(15,15,20,.04);
  --radius:14px;
  --sidebar-w:280px;
  --topbar-h:56px;
}
*{box-sizing:border-box}
html,body{margin:0;padding:0;background:var(--sand);color:var(--ink);font-family:"Inter",-apple-system,BlinkMacSystemFont,"Segoe UI",Helvetica,Arial,sans-serif;font-size:14px;line-height:1.5;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
code{font-family:"JetBrains Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.85em;background:var(--brand-tint);color:var(--brand);padding:1px 6px;border-radius:6px}

.app{display:grid;grid-template-columns:var(--sidebar-w) 1fr;min-height:100vh}

/* ---- Sidebar ---- */
.sidebar{
  background:var(--paper);
  border-right:1px solid var(--line);
  display:flex;flex-direction:column;
  position:sticky;top:0;height:100vh;
  z-index:30;
}
.brand{display:flex;align-items:center;gap:10px;padding:16px 18px;border-bottom:1px solid var(--line);min-height:var(--topbar-h)}
.brand-mark{display:grid;place-items:center;width:32px;height:32px;border-radius:8px;background:var(--brand);color:#fff}
.brand-text{flex:1;min-width:0}
.brand-title{font-weight:700;letter-spacing:-.01em;font-size:15px;line-height:1.1}
.brand-sub{font-size:11.5px;color:var(--ink-3);margin-top:2px;text-transform:uppercase;letter-spacing:.04em}
.sidebar-close{display:none;color:var(--ink-3);padding:6px}

.search{padding:12px 14px 8px}
.search input{
  width:100%;padding:9px 12px;border:1px solid var(--line);border-radius:10px;background:#fafaf8;outline:none;
  font-size:13px;color:var(--ink);
}
.search input:focus{border-color:var(--brand);background:#fff;box-shadow:0 0 0 3px var(--brand-tint)}

.nav{flex:1;overflow-y:auto;padding:6px 8px 14px}
.group{padding:10px 8px 6px}
.group-h{font-size:11px;text-transform:uppercase;letter-spacing:.07em;color:var(--ink-3);font-weight:600;padding:0 8px 6px}
.doc-link{
  display:flex;align-items:center;gap:8px;
  padding:8px 10px;border-radius:8px;
  color:var(--ink-2);font-size:13.5px;line-height:1.35;
  cursor:pointer;
}
.doc-link:hover{background:#f3f0ea;color:var(--ink)}
.doc-link.active{background:var(--brand-tint);color:var(--brand);font-weight:600}
.doc-link .dot{width:6px;height:6px;border-radius:50%;background:currentColor;opacity:.4;flex:0 0 auto}
.doc-link .t{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}

.sidebar-foot{border-top:1px solid var(--line);padding:12px 16px;background:#fafaf8}
.who{font-size:12.5px;color:var(--ink-2);font-weight:500}
.who-sub{font-size:11.5px;color:var(--ink-3);display:inline-block;margin-top:3px}
.who-sub:hover{color:var(--brand)}

/* ---- Main ---- */
.main{display:flex;flex-direction:column;min-height:100vh;background:var(--sand)}
.topbar{
  position:sticky;top:0;z-index:20;
  height:var(--topbar-h);display:flex;align-items:center;gap:10px;
  padding:0 20px;background:rgba(246,243,236,.9);backdrop-filter:saturate(140%) blur(8px);
  border-bottom:1px solid var(--line);
}
.menu-btn{display:none;color:var(--ink-2);padding:6px}
.crumbs{flex:1;min-width:0;font-size:13px;color:var(--ink-2);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.crumb{color:var(--ink-3)}
.crumb.active{color:var(--ink);font-weight:600}
.crumb-sep{padding:0 8px;color:var(--ink-3)}
.open-new{font-size:12.5px;color:var(--ink-3);padding:6px 10px;border-radius:8px}
.open-new:hover{color:var(--brand);background:var(--brand-tint)}

.pane{position:relative;flex:1;display:flex;flex-direction:column;min-height:0}

/* welcome */
.welcome{padding:48px 28px 80px;max-width:1080px;width:100%;margin:0 auto}
.welcome h1{font-size:34px;line-height:1.1;letter-spacing:-.02em;margin:0 0 8px;font-weight:700}
.welcome .lede{font-size:16px;color:var(--ink-2);max-width:680px;margin:0 0 28px}
.welcome-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:14px}
.doc-card{
  display:block;background:var(--paper);border:1px solid var(--line);border-radius:var(--radius);
  padding:18px 18px 16px;box-shadow:var(--shadow-sm);transition:transform .12s ease, box-shadow .12s ease, border-color .12s ease;
  cursor:pointer;
}
.doc-card:hover{transform:translateY(-1px);box-shadow:var(--shadow-md);border-color:#d9d6d0}
.doc-card-tag{display:inline-block;font-size:10.5px;text-transform:uppercase;letter-spacing:.07em;font-weight:600;color:var(--brand);background:var(--brand-tint);padding:3px 8px;border-radius:999px;margin-bottom:10px}
.doc-card h3{margin:0 0 4px;font-size:16px;letter-spacing:-.01em}
.doc-card p{margin:0;color:var(--ink-2);font-size:13px;line-height:1.45}
.doc-card-meta{margin-top:12px;padding-top:10px;border-top:1px solid var(--line);display:flex;justify-content:space-between;font-size:11.5px;color:var(--ink-3)}

.welcome-foot{margin-top:36px;padding:16px 18px;background:var(--paper);border:1px dashed var(--line);border-radius:12px;color:var(--ink-2);font-size:13px}
.welcome-foot p{margin:0}

/* iframe pane */
.frame{flex:1;width:100%;border:0;background:var(--paper)}

/* ---- Responsive ---- */
@media (max-width: 900px){
  :root{--sidebar-w:260px}
  .app{grid-template-columns:1fr}
  .sidebar{position:fixed;top:0;left:0;width:280px;transform:translateX(-100%);transition:transform .22s ease;box-shadow:var(--shadow-md)}
  .sidebar.open{transform:translateX(0)}
  .menu-btn{display:inline-flex}
  .sidebar-close{display:inline-flex}
  .welcome{padding:32px 18px 60px}
  .welcome h1{font-size:26px}
}

/* dim overlay when sidebar open on mobile */
.scrim{position:fixed;inset:0;background:rgba(15,15,20,.35);z-index:25;opacity:0;pointer-events:none;transition:opacity .18s ease}
.scrim.show{opacity:1;pointer-events:auto}