body {
  font-family: Arial, sans-serif;
  margin: 0; padding: 0;
  background-color: #111;
  color: #eee;
}
header, nav, footer {
  padding: 1em;
  background: #222;
  text-align: center;
}
nav a {
  margin: 0 1em;
  color: #0af;
  text-decoration: none;
}
svg {
  display: block;
  margin: auto;
  background: #000;
  border: 1px solid #333;
}