.css-class-add, .css-class-remove {
  transition: all 0.5s cubic-bezier(0.250, 0.460, 0.450, 0.940);
}

.css-class,
.css-class-add.css-class-add-active {
  color: red;
  font-size: 3em;
}

.css-class-remove.css-class-remove-active {
  font-size: 1em;
  color: black;
}