.placeholder {
  display: inline-block;
  min-height: 1em;
  vertical-align: middle;
  cursor: wait;
  background-color: currentcolor;
  opacity: 0.5;
}
.placeholder.btn::before {
  display: inline-block;
  content: "";
}

.placeholder-xs {
  min-height: 0.6em;
}

.placeholder-sm {
  min-height: 0.8em;
}

.placeholder-lg {
  min-height: 1.2em;
}

.placeholder-glow .placeholder {
  animation: placeholder-glow 2s ease-in-out infinite;
}

@keyframes placeholder-glow {
  50% {
    opacity: 0.2;
  }
}
.placeholder-wave {
  mask-image: linear-gradient(130deg, #000 55%, rgba(0, 0, 0, 0.8) 75%, #000 95%);
  mask-size: 200% 100%;
  animation: placeholder-wave 2s linear infinite;
}

@keyframes placeholder-wave {
  100% {
    mask-position: -200% 0%;
  }
}