body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background: #f5f5f5;
  color: #333;
}

header, footer {
  background-color: #333;
  color: #fff;
  padding: 10px;
}

nav ul {
  list-style-type: none;
  padding: 0;
  text-align: center;
}

nav ul li {
  display: inline;
  margin: 0 15px;
}

nav ul li a {
  color: #fff;
  text-decoration: none;
}

main {
  padding: 20px;
}

h1, h2, h3 {
  text-align: center;
}

form {
  max-width: 600px;
  margin: 0 auto;
  background: #fff;
  padding: 20px;
  border: 1px solid #ddd;
}