:root {
  --bg-0: #07090f;
  --bg-1: #0b0f1a;
  --bg-2: #111827;
  --border: #1e2d42;
  --text: #e2e8f4;
  --muted: #8a9ab8;
  --brand: #3B82F6;
  --brand2: #22D3EE;
  --answer: #a7f3d0;
  --example: #fcd7a1;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: radial-gradient(1200px 600px at 50% -10%, #0d1524, var(--bg-0));
  color: var(--text);
  font-family: var(--font);
  min-height: 100vh;
  line-height: 1.55;
}

/* Header */
header.top {
  border-bottom: 1px solid var(--border);
  padding: 20px 24px;
  background: rgba(7, 9, 15, 0.7);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 20;
}
header.top .eyebrow { text-transform: uppercase; letter-spacing: .18em; font-size: 11px; color: var(--brand2); font-weight: 700; }
header.top h1 { font-size: clamp(20px, 3vw, 30px); margin-top: 6px; line-height: 1.15; }
header.top h1 .grad { background: linear-gradient(90deg, var(--brand), var(--brand2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
header.top .sub { color: var(--muted); font-size: 14px; margin-top: 6px; }
header.top .home { color: var(--brand2); text-decoration: none; font-size: 13px; font-weight: 600; }

/* Layout */
.layout { display: grid; grid-template-columns: 300px 1fr; gap: 0; align-items: start; }

/* Sidebar */
aside.nav {
  position: sticky;
  top: 97px;
  max-height: calc(100vh - 97px);
  overflow-y: auto;
  border-right: 1px solid var(--border);
  padding: 20px 14px 40px;
}
aside.nav .navtitle { font-size: 11px; text-transform: uppercase; letter-spacing: .14em; color: var(--muted); padding: 0 10px 10px; }
aside.nav a {
  display: flex; justify-content: space-between; gap: 8px; align-items: center;
  text-decoration: none; color: var(--text); font-size: 13px;
  padding: 8px 10px; border-radius: 8px; margin-bottom: 2px;
  border: 1px solid transparent;
}
aside.nav a:hover { background: var(--bg-2); border-color: var(--border); }
aside.nav a .gnum { color: var(--brand2); font-weight: 700; font-size: 11px; min-width: 22px; }
aside.nav a .gcount { color: var(--muted); font-size: 11px; }
aside.nav a span.gname { flex: 1; }

/* Main */
main { padding: 26px clamp(16px, 4vw, 48px) 80px; max-width: 1000px; }
section.group { margin-bottom: 40px; scroll-margin-top: 110px; }
section.group > h2 {
  font-size: 20px; margin-bottom: 4px;
  padding-bottom: 10px; border-bottom: 1px solid var(--border);
}
section.group > h2 .gid { color: var(--brand2); font-weight: 700; margin-right: 8px; }
section.group .gmeta { color: var(--muted); font-size: 12px; margin: 6px 0 16px; }

/* Q&A card */
details.qa {
  border: 1px solid var(--border); border-radius: 12px;
  background: linear-gradient(180deg, rgba(17,24,39,.7), rgba(11,15,26,.7));
  margin-bottom: 10px; overflow: hidden;
}
details.qa > summary {
  cursor: pointer; list-style: none; padding: 14px 18px;
  font-weight: 600; font-size: 15px; display: flex; gap: 10px; align-items: flex-start;
}
details.qa > summary::-webkit-details-marker { display: none; }
details.qa > summary .chev { color: var(--brand2); transition: transform .15s ease; flex-shrink: 0; }
details.qa[open] > summary .chev { transform: rotate(90deg); }
details.qa > summary:hover { color: var(--brand2); }
.qa .body { padding: 0 18px 16px 42px; }
.qa .block { margin-top: 10px; }
.qa .label { font-size: 11px; text-transform: uppercase; letter-spacing: .1em; font-weight: 700; margin-bottom: 4px; }
.qa .label.ans { color: var(--answer); }
.qa .label.ex { color: var(--example); }
.qa .text { color: var(--text); font-size: 14.5px; }
.qa .text.ex { color: #d7e0f0; background: rgba(252,215,161,.06); border-left: 3px solid var(--example); padding: 8px 12px; border-radius: 0 8px 8px 0; }

/* Controls */
.controls { display: flex; gap: 10px; flex-wrap: wrap; margin: 4px 0 22px; }
.controls button {
  background: var(--bg-2); color: var(--text); border: 1px solid var(--border);
  border-radius: 8px; padding: 8px 14px; font-size: 13px; cursor: pointer; font-family: var(--font);
}
.controls button:hover { border-color: var(--brand); color: var(--brand2); }

footer { color: var(--muted); font-size: 13px; text-align: center; padding: 26px; border-top: 1px solid var(--border); }
footer a { color: var(--brand2); text-decoration: none; }

.loading { padding: 60px 20px; text-align: center; color: var(--muted); }

/* Mobile */
@media (max-width: 860px) {
  .layout { grid-template-columns: 1fr; }
  aside.nav { position: static; max-height: none; border-right: none; border-bottom: 1px solid var(--border); }
  aside.nav .navlist { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px,1fr)); gap: 4px; }
}