:root{
  --bg:#0b0f13;
  --panel:#0f1720;
  --muted:#9aa4ad;
  --accent:#28c2b1;
  --glass: rgba(255,255,255,0.03);
  --radius:12px;
  --max-width:1100px;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial;
}

*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  background:linear-gradient(180deg,var(--bg),#071018);
  color:#e6eef1;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

.container{
  display:grid;
  grid-template-columns:320px 1fr;
  gap:28px;
  max-width:var(--max-width);
  margin:32px auto;
  padding:24px;
  align-items:start;
}

/* TOC (left) */
.toc{
  position:sticky;
  top:24px;
  height:calc(100vh - 48px);
  background:linear-gradient(180deg, rgba(255,255,255,0.02), rgba(255,255,255,0.01));
  border-radius:var(--radius);
  padding:20px;
  box-shadow:0 6px 30px rgba(3,7,9,0.6);
  display:flex;
  flex-direction:column;
  justify-content:space-between;
}

.brand{
  display:flex;
  align-items:center;
  gap:12px;
}
.brand h1{
  font-size:1.05rem;
  margin:0;
  letter-spacing:0.2px;
}
.toc-toggle{
  margin-left:auto;
  display:none;
  background:transparent;
  color:var(--muted);
  border:1px solid rgba(255,255,255,0.03);
  padding:6px 8px;
  border-radius:8px;
  cursor:pointer;
}

.toc nav ul{
  list-style:none;
  padding:18px 0 0 0;
  margin:0;
}
.toc nav a{
  display:block;
  padding:10px 12px;
  color:var(--muted);
  text-decoration:none;
  border-radius:8px;
  transition:all .18s ease;
  font-weight:600;
  margin-bottom:6px;
}
.toc nav a:hover, .toc nav a.active{
  color:var(--accent);
  background:linear-gradient(90deg, rgba(40,194,177,0.06), transparent);
  transform:translateX(4px);
}

.meta{color:var(--muted); font-size:12px; margin-top:8px}

/* Content (right) */
.content{
  background:linear-gradient(180deg, rgba(255,255,255,0.01), transparent);
  padding:28px;
  border-radius:var(--radius);
  box-shadow:0 6px 40px rgba(3,7,9,0.6);
  min-height:60vh;
}
.content h2{color:#fff; margin-top:0}
.content p, .content li, .content dd{color:var(--muted); line-height:1.6}

.content a{color:var(--accent); text-decoration:underline}

.page-footer{
  display:flex;
  gap:12px;
  align-items:center;
  margin-top:28px;
}
.btn{
  background:transparent;
  border:1px solid rgba(255,255,255,0.06);
  padding:8px 12px;
  border-radius:10px;
  color:var(--muted);
  text-decoration:none;
  cursor:pointer;
}

/* Responsive */
@media (max-width:880px){
  .container{grid-template-columns:1fr; padding:12px}
  .toc{position:relative; height:auto; display:flex; padding:12px 12px 8px 12px; margin-bottom:12px}
  .toc-toggle{display:inline-block}
  .toc nav{display:none}
  .toc nav.open{display:block}
}