body, html {
  margin: 0;
  padding: 0;
  font-size: 4vw;
  height: 100%;
}
body {
  display: flex;
  align-items: center;
  justify-content: center;
}
code {
  display: block;
  transition: color 1s;
}
.s, .n {
  color: black;
  transition: color 1s;
}
.s.a {
  color: red;
}
.n.a {
  color: grey;
}