:root {
  --bg: #f7f9fb;
  --card: #ffffff;
  --muted: #6b7280;
  --accent: #2563eb;
}

body {
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial;
  margin: 0;
  background: var(--bg);
  color: #0f172a;
}

header {
  background: linear-gradient(90deg, #111827, #0f172a);
  color: #fff;
  padding: 28px 20px;
}

.container {
  max-width: 900px;
  margin: 24px auto;
  padding: 0 20px;
}

.card {
  background: var(--card);
  border-radius: 12px;
  padding: 26px;
  box-shadow: 0 6px 18px rgba(2, 6, 23, 0.06);
}

h1 {
  margin: 0 0 8px;
  font-size: 1.6rem;
}

p.lead {
  margin: 0;
  color: var(--muted);
}

h2 {
  margin-top: 22px;
  font-size: 1.05rem;
}

p {
  line-height: 1.55;
  color: #0b1220;
}

ul {
  margin: 8px 0 8px 20px;
}

code {
  background: #f3f4f6;
  padding: 2px 6px;
  border-radius: 6px;
}

footer {
  margin: 22px 0 60px;
  color: var(--muted);
  font-size: 0.95rem;
}

.muted {
  color: var(--muted);
}

a {
  color: var(--accent);
  text-decoration: none;
}

.btn {
  display: inline-block;
  padding: 10px 14px;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
}

@media (max-width: 600px) {
  header { padding: 20px; }
  .card { padding: 18px; }
}