body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f4f4f4;
  color: #333;
}

header {
  background-color: #222;
  color: #fff;
  padding: 1em;
  text-align: center;
}

main {
  padding: 2em;
}