html, 
body {
  height: 100%;
}

body {
  align-items: center;
  display: flex;
  font-family: Arial, "Helvetica Neue", Helvetica, sans-serif;
  justify-content: center;
  margin: 0;
}

body.boris {
  background: #171717;
}

body.david {
  background: #d72427;
}

#message {
  color: #FFFFFF;
  font-size: 5.5rem;
  font-weight: 700;
  line-height: 1;
  text-align: center;
  text-transform: uppercase;
}

@media only screen and (max-width: 768px) {
  /* For mobile phones: */
  #message {
    font-size: 3rem;
  }
}

#footer {
  align-items: center;
  bottom: 0;
  color: #FFFFFF;
  display: flex;
  font-size: 1rem;
  height: 3rem;
  justify-content: center;
  left: 0;
  padding: 1rem;
  position: absolute;
  right: 0;
  text-align: center;
  text-transform: uppercase;
}

#footer a {
  color: #FFFFFF;
}