body {
  margin: 0;
  padding: 0;
  font-family: sans-serif;
}

.Demo-logo {
  animation: Demo-logo-spin infinite 20s linear;
  height: 50px;
}

.Demo-header {
  text-align: center;
  background-color: #222;
  min-height: 150px;
  padding: 20px;
  color: white;
}

.Demo-header-links {
  font-size : 2.1rem;
}

.Demo-intro {
  text-align: center;
  font-size: large;
}

@keyframes Demo-logo-spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}