spee.ch/client/scss/_button-secondary.scss

.button--secondary, .button--secondary:focus, .button--secondary:active  {
  border-bottom-color: $secondary-color;
  color: $secondary-color;
  background-color: $background-color;
}

.button--secondary:active {
  $color: darken($secondary-color, 10%);
  color: $color;
  border-bottom-color: $color;
}