.alt-theme-color {
  color: #fff;
  background: #333;
}

.theme-color-switch {
  display: inline-block;
  padding: .5rem 1.5rem;
  border: 2px solid rgb(12, 180, 90);
  border-radius: 5px;
  font-weight: bold;
  cursor: pointer;
  font-size: 1.25em;
  color: #fff ;
  background: rgb(12, 180, 90);
  transition: all .3s ease;
}

.theme-color-switch:after {
  content: attr(data-text-off);
}

.switch-on {
  background-color: transparent;
  color:  rgb(12, 180, 90);
}

.switch-on:after {
  content: attr(data-text-on);
}