body {
  font-family: Arial, sans-serif;
  background: #f5f8fa;
  margin: 0;
  padding: 0;
}
header, footer {
  background-color: #004080;
  color: white;
  text-align: center;
  padding: 1em;
}
nav {
  background-color: #0066cc;
  text-align: center;
  padding: 0.5em;
}
nav a {
  color: white;
  margin: 0 15px;
  text-decoration: none;
}
main {
  padding: 2em;
}
ul {
  padding-left: 20px;
}