body {
  font-family: Arial, sans-serif;
  background-color: #f4f4f4;
  margin: 0;
  padding: 0;
}
header, footer {
  background-color: #222;
  color: white;
  padding: 1rem;
  text-align: center;
}
nav a {
  color: #00bfff;
  margin: 0 1rem;
  text-decoration: none;
}
main {
  max-width: 800px;
  margin: 2rem auto;
  background: white;
  padding: 2rem;
  border-radius: 8px;
}