body{
  font-family: Arial, Helvetica, sans-serif;
  margin: auto;
  max-width: 40em;
  padding:1em;
}
.demo{
  padding: 0 0 2em 2em;
}
.introNB{
  font-style: italic;
}
.placeholder{
  font-style: italic;
  opacity: 0.5;
}