:root {
  --bg: #0b0d12;
  --panel: #141824;
  --rail: #0f121a;
  --text: #eef0f6;
  --muted: #8b93a7;
  --accent: #7c6cff;
  --accent-2: #a78bfa;
  --ok: #34d399;
  --warn: #fbbf24;
  --border: #262b3a;
  --mono: "JetBrains Mono", ui-monospace, Menlo, monospace;
  --sans: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
  --radius: 6px;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
  min-height: 100vh;
}
.shell-a-hero {
  border-bottom: 1px solid var(--border);
  padding: 1.25rem 1.5rem 1.5rem;
  background: linear-gradient(180deg, #12131c 0%, var(--bg) 100%);
}
.shell-a-brand {
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  font-weight: 700;
  color: var(--muted);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-transform: uppercase;
}
.shell-a-mark { color: var(--accent); font-size: 1.1rem; letter-spacing: 0; }
.shell-a-rail {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 1rem;
  margin: 1rem 0 0.75rem;
  padding: 0;
  list-style: none;
}
.shell-a-rail a {
  color: var(--accent-2);
  text-decoration: none;
  font-size: 0.85rem;
  border-bottom: 2px solid transparent;
  padding-bottom: 0.15rem;
}
.shell-a-rail a[aria-current="page"] {
  border-bottom-color: var(--accent);
  color: var(--text);
  font-weight: 600;
}
.shell-a-kicker {
  margin: 0;
  color: var(--muted);
  font-size: 0.8rem;
  letter-spacing: 0.04em;
}
.shell-a-hero h1 {
  margin: 0.35rem 0 0;
  font-size: clamp(1.5rem, 3.5vw, 2.1rem);
  letter-spacing: -0.03em;
  max-width: 36rem;
  font-weight: 650;
}
.shell-a-layout {
  display: grid;
  gap: 0;
  max-width: 1080px;
  margin: 0 auto;
}
@media (min-width: 860px) {
  .shell-a-layout { grid-template-columns: 200px 1fr; min-height: 70vh; }
}
.shell-a-steps {
  background: var(--rail);
  border-right: 1px solid var(--border);
  padding: 1.25rem 1rem;
  font-size: 0.82rem;
  color: var(--muted);
}
.shell-a-steps ol { margin: 0; padding-left: 1.1rem; }
.shell-a-steps li { margin: 0.55rem 0; }
.shell-a-steps .done { color: var(--ok); }
.shell-a-steps .current { color: var(--accent-2); font-weight: 600; }
.shell-a-body { padding: 1.5rem 1.35rem 3rem; max-width: 720px; }
.step-card {
  margin-top: 1rem;
  padding: 1.1rem 1.15rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel);
  border-left: 3px solid var(--accent);
}
.step-card h2 { margin: 0 0 0.7rem; font-size: 1.05rem; }
.choice {
  display: block;
  margin: 0.4rem 0;
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  background: #0e1018;
}
.choice:hover, .choice:focus-within { border-color: var(--accent); }
.choice input { margin-right: 0.5rem; accent-color: var(--accent); }
.result-box {
  margin-top: 1.25rem;
  padding: 1rem 1.1rem;
  border-radius: var(--radius);
  border: 1px solid #2d4a3a;
  background: #0f1c18;
}
.result-box.warn-path { border-color: #5a4a20; background: #1c180c; }
.checklist { list-style: none; padding: 0; margin: 0.75rem 0 0; }
.checklist li {
  margin: 0.35rem 0;
  padding: 0.5rem 0.6rem;
  border-radius: var(--radius);
  background: #0e1018;
  border: 1px dashed var(--border);
}
button {
  border: none;
  border-radius: var(--radius);
  padding: 0.55rem 1rem;
  background: var(--accent);
  color: #0b0d12;
  font-weight: 700;
  cursor: pointer;
}
button.secondary { background: #2a3144; color: var(--text); }
.badge {
  display: inline-block;
  padding: 0.15rem 0.5rem;
  border-radius: 999px;
  background: #1e1840;
  color: var(--accent-2);
  font-size: 0.75rem;
}
.prose h2 { margin-top: 1.6rem; font-size: 1.15rem; }
.prose p, .prose li { color: var(--muted); }
footer {
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.78rem;
}
footer a { color: var(--accent-2); }
/* shared matrix pages keep class names; chrome differs */
.wrap { max-width: 920px; margin: 0 auto; padding: 1.5rem 1.25rem 3rem; }
.site-nav { display: none; } /* use shell-a-rail instead */