:root {
  --bg: #071018;
  --panel: #0d1820;
  --line: #243540;
  --text: #e8eef0;
  --muted: #8aa0a8;
  --amber: #ffb020;
  --cyan: #5fd8e8;
  --blue: #38bdf8;
  --font: "Segoe UI", system-ui, -apple-system, sans-serif;
  --mono: "SF Mono", "Cascadia Code", Menlo, monospace;
}

* { box-sizing: border-box; }
html, body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(ellipse 80% 50% at 20% 0%, rgba(56, 189, 248, 0.12), transparent),
    radial-gradient(ellipse 60% 40% at 90% 80%, rgba(255, 176, 32, 0.1), transparent),
    var(--bg);
  color: var(--text);
  font-family: var(--font);
}

.hub {
  max-width: 920px;
  margin: 0 auto;
  padding: 3rem 1.5rem 2rem;
}

.hub-eyebrow {
  margin: 0;
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--cyan);
}

.hub-title {
  margin: 0.6rem 0 0.4rem;
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 650;
  letter-spacing: 0.02em;
}

.hub-sub {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.hub-grid {
  display: grid;
  gap: 1rem;
  margin-top: 2.2rem;
}

@media (min-width: 720px) {
  .hub-grid { grid-template-columns: 1fr 1fr; }
}

.sim-card {
  display: block;
  text-decoration: none;
  color: inherit;
  background: var(--panel);
  border: 1px solid var(--line);
  padding: 1.4rem 1.3rem 1.3rem;
  transition: border-color 0.15s, transform 0.15s;
}

.sim-card:hover {
  border-color: var(--amber);
  transform: translateY(-2px);
}

.sim-card.takeoff { border-top: 3px solid var(--blue); }
.sim-card.missile_interception { border-top: 3px solid var(--amber); }
.sim-card.combat_radius { border-top: 3px solid #3ddc84; }
.sim-card.missile_range { border-top: 3px solid #c084fc; }

.sim-id {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  color: var(--muted);
  text-transform: uppercase;
  line-height: 1.35;
  word-break: break-word;
}

.sim-name {
  margin: 0.55rem 0 0.35rem;
  font-size: 1.2rem;
  font-weight: 600;
}

.sim-sub {
  margin: 0;
  color: var(--muted);
  font-size: 0.88rem;
  line-height: 1.45;
}

.sim-cta {
  margin-top: 1.1rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--amber);
}

.hub-loading, .hub-error {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.85rem;
}

.hub-error { color: #f87171; }

.hub-footer {
  margin-top: 2.5rem;
  font-size: 0.75rem;
  color: var(--muted);
  font-family: var(--mono);
}