body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: #f5f5f7;
  color: #1d1d1f;
  margin: 0;
  padding: 0;
}

header {
  padding: 24px;
  text-align: center;
}

nav a {
  margin: 0 12px;
  text-decoration: none;
  color: #0066cc;
  font-weight: 500;
}

main {
  max-width: 700px;
  margin: 40px auto;
  padding: 0 20px;
}

footer {
  text-align: center;
  padding: 40px 20px;
  font-size: 0.9em;
  color: #6e6e73;
}