body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background: #fefefe;
  color: #333;
}
header, footer {
  background: #111;
  color: #fff;
  text-align: center;
  padding: 2rem 1rem;
}
nav {
  background: #333;
  text-align: center;
}
nav a {
  color: #fff;
  display: inline-block;
  padding: 1rem;
  text-decoration: none;
}
nav a:hover {
  background: #555;
}
section {
  padding: 3rem 2rem;
  max-width: 800px;
  margin: auto;
}
h1, h2, h3 {
  margin-bottom: 1rem;
}