body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background: #f5f5f5;
}
header {
  background: #004080;
  color: white;
  padding: 15px;
  text-align: center;
}
header h1 { margin: 0; }
nav ul { list-style: none; padding: 0; }
nav ul li { display: inline-block; margin: 0 15px; }
nav ul li a { color: white; text-decoration: none; }
main {
  padding: 20px;
  background: white;
  min-height: 400px;
}
footer {
  text-align: center;
  padding: 15px;
  background: #ddd;
}