body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  background-color: #f0f0f0;
}

header {
  text-align: center;
  margin-bottom: 20px;
}

nav ul {
  list-style: none;
  padding: 0;
}

nav ul li {
  margin: 10px 0;
}

nav ul li a {
  text-decoration: none;
  color: #333;
  font-size: 18px;
}