:root {
  --primary: #4f46e5;
  --text-main: #1f2937;
  --text-muted: #6b7280;
  --bg-subtle: #f9fafb;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  line-height: 1.6;
  color: var(--text-main);
  margin: 0;
  padding: 0;
}

nav {
  background: white;
  border-bottom: 1px solid #e5e7eb;
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

nav .links {
  display: flex;
  gap: 1.5rem;
}

nav a {
  text-decoration: none;
  color: var(--text-main);
  font-weight: 500;
}

.container {
  max-width: 800px;
  margin: 3rem auto;
  padding: 0 1rem;
}

header {
  margin-bottom: 2rem;
  text-align: center;
}

h1 { font-size: 2.5rem; margin-bottom: 0.5rem; }
p.lead { font-size: 1.25rem; color: var(--text-muted); }

.card {
  background: white;
  border: 1px solid #e5e7eb;
  border-radius: 0.5rem;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

footer {
  text-align: center;
  padding: 2rem;
  color: var(--text-muted);
  font-size: 0.875rem;
  border-top: 1px solid #e5e7eb;
}