body {
  background-color: #111;
  color: #0f0;
  font-family: 'Courier New', Courier, monospace;
  margin: 0;
  padding: 0;
}
header {
  background: #000;
  padding: 20px;
  text-align: center;
}
nav a {
  color: #0f0;
  margin: 0 15px;
  text-decoration: none;
  font-weight: bold;
}
main {
  padding: 20px;
}
footer {
  background: #000;
  color: #0f0;
  text-align: center;
  padding: 10px;
  position: fixed;
  width: 100%;
  bottom: 0;
}