body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f1f1f1;
  color: #222;
}

header, nav {
  background-color: #004d40;
  color: white;
  padding: 1em;
  text-align: center;
}

nav a {
  color: white;
  margin: 0 1em;
  text-decoration: none;
  font-weight: bold;
}

main {
  padding: 2em;
  max-width: 700px;
  margin: auto;
}

footer {
  text-align: center;
  font-size: 0.9em;
  padding: 1em;
  background-color: #ddd;
}