html {
  background-color: #333;
  color: #fff;
  font-family: helvetica, Arial, sans-serif;
}
html body {
  width: 640px;
  margin: 1rem auto;
  text-align: center;
}
html a {
  color: #fc0;
}
html a.visited {
  color: #f60;
}
html footer {
  margin-top: 1rem;
  border-top: solid 1px;
  font-size: 0.8rem;
}