.opacity-0 {
  opacity: 0;
}

.opacity-1 {
  background: rgba(0, 0, 0, 0.5);
}

.opacity-2 {
  opacity: 0.4;
}

.opacity-3 {
  opacity: 0.6;
}

.opacity-4 {
  opacity: .8;
}

.opacity-5 {
  opacity: 1;
}