body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background: #f4f4f4;
}
header {
  text-align: center;
  background: #222;
  color: #fff;
  padding: 40px 0;
}
section {
  padding: 20px;
  max-width: 800px;
  margin: auto;
  background: #fff;
  margin-top: 20px;
  border-radius: 8px;
}