body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f4f4f9;
}
header {
  background-color: #6200ea;
  color: #fff;
  padding: 20px;
  text-align: center;
}
nav {
  display: flex;
  justify-content: center;
  background: #3700b3;
  padding: 10px 0;
}
nav a {
  color: white;
  margin: 0 15px;
  text-decoration: none;
}