:root {
  color-scheme: dark;
  --bg: #070b16;
  --card: #111a2e;
  --border: #24304d;
  --text: #e8eefc;
  --muted: #9aaccf;
  --accent: #5b8cff;
  --accent2: #3dd6c6;
  --danger: #ff6b8a;
  --ok: #3ecf8e;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "DM Sans", system-ui, sans-serif;
  background:
    radial-gradient(1200px 600px at 10% -10%, #1a2744 0%, transparent 55%),
    radial-gradient(900px 500px at 100% 0%, #12353a 0%, transparent 50%),
    var(--bg);
  color: var(--text);
  line-height: 1.55;
  min-height: 100vh;
}
.wrap { max-width: 960px; margin: 0 auto; padding: 1.25rem 1.25rem 4rem; }
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}
.logo {
  font-weight: 800;
  color: #fff;
  text-decoration: none;
  letter-spacing: -0.02em;
}
.nav-links { display: flex; align-items: center; gap: 0.75rem; flex-wrap: wrap; }
.nav-links a { color: var(--muted); text-decoration: none; font-weight: 600; font-size: 0.92rem; }
.nav-links a:hover { color: #fff; }
header { margin-bottom: 2rem; }
.badge {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent2);
  border: 1px solid rgba(61, 214, 198, 0.35);
  background: rgba(61, 214, 198, 0.08);
  padding: 0.3rem 0.65rem;
  border-radius: 999px;
  margin-bottom: 1rem;
}
h1 {
  font-size: clamp(1.75rem, 5vw, 2.6rem);
  line-height: 1.12;
  letter-spacing: -0.03em;
  margin: 0 0 0.75rem;
  font-weight: 800;
}
h2 { margin: 0 0 0.75rem; font-size: 1.35rem; }
.lead { color: var(--muted); font-size: 1.1rem; max-width: 38rem; margin: 0 0 1.5rem; }
.cta { display: flex; flex-wrap: wrap; gap: 0.75rem; }
a.btn, button.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  text-decoration: none;
  font-weight: 700;
  border-radius: 12px;
  padding: 0.85rem 1.2rem;
  border: 1px solid transparent;
  cursor: pointer;
  font-family: inherit;
  font-size: 0.95rem;
}
.btn-sm { padding: 0.55rem 0.9rem; font-size: 0.88rem; }
.btn-primary {
  background: linear-gradient(180deg, #4f7ff0, #2f5bc4);
  color: #fff;
  box-shadow: 0 8px 24px rgba(61, 111, 224, 0.35);
  border: none;
}
.btn-ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin: 2rem 0;
}
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.15rem 1.2rem;
  margin-bottom: 1rem;
}
.card h3 { margin: 0 0 0.4rem; font-size: 1.05rem; }
.card p { margin: 0; color: var(--muted); font-size: 0.95rem; }
.card p + p { margin-top: 0.75rem; }
.fine { color: var(--muted); font-size: 0.9rem; margin: 1rem 0 0; }
.fine a, footer a { color: var(--accent); }
code {
  background: rgba(255,255,255,0.06);
  padding: 0.1rem 0.35rem;
  border-radius: 4px;
  font-size: 0.88em;
}
footer { color: var(--muted); font-size: 0.85rem; margin-top: 2.5rem; }

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--card);
  color: var(--text);
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: 0 0 8px 0;
  z-index: 10;
}
.skip-link:focus { left: 0; }

:focus-visible {
  outline: 3px solid #8fb4ff;
  outline-offset: 2px;
  border-radius: 6px;
}

.btn { min-height: 44px; display: inline-flex; align-items: center; justify-content: center; }
.btn-sm { min-height: 44px; }

.prereq-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.25rem;
  margin: 1.25rem 0;
  padding: 0.85rem 1rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: rgba(91, 140, 255, 0.06);
  font-size: 0.92rem;
  color: var(--muted);
}

.code-block {
  background: #0a1122;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.9rem 1rem;
  overflow-x: auto;
  font-size: 0.85rem;
  line-height: 1.6;
}
.code-block code { white-space: pre; background: transparent; padding: 0; }

@media (max-width: 640px) {
  .nav-links { flex-wrap: wrap; gap: 0.5rem; }
  .nav-links a:not(.btn) { font-size: 0.9rem; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

@media print {
  body { background: #fff; color: #000; }
  .wrap, .card, .code-block { background: #fff; color: #000; border-color: #999; }
  .nav, .cta, .skip-link { display: none; }
  a { color: #000; text-decoration: underline; }
}