@keyframes spinner-border {
  to { transform: rotate(360deg); }
}

.spinner-border {
  display: inline-block;
  width: 2rem;
  height: 2rem;
  vertical-align: text-bottom;
  border: .25em solid currentColor;
  border-right-color: transparent;
  border-radius: 50%;
  animation: spinner-border .75s linear infinite;
}

@keyframes spinner-grow {
  0% {
    transform: scale(0);
  }
  50% {
    opacity: 1;
  }
}

.spinner-grow {
  display: inline-block;
  width: 2rem;
  height: 2rem;
  vertical-align: text-bottom;
  background-color: currentColor;
  border-radius: 50%;
  opacity: 0;
  animation: spinner-grow .75s linear infinite;
}

.visible {
  visibility: visible;
}
.invisible {
  visibility: hidden;
}