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

.spinner-border {
  position: relative;
  display: inline-block;
  width: 2rem;
  height: 2rem;
  overflow: hidden;
  text-indent: -999em;
  border: .25em solid;
  border-color: currentColor transparent currentColor currentColor;
  border-radius: 50%;
  animation-name: spinner-border;
  animation-duration: .75s;
  animation-timing-function: linear;
  animation-iteration-count: infinite;
}

.spinner-border-reverse {
  border-color: transparent currentColor transparent transparent;

  &::after {
    position: absolute;
    top: -.25em;
    right: -.25em;
    bottom: -.25em;
    left: -.25em;
    display: inline-block;
    content: "";
    border: .25em solid rgba(0,0,0,.1);
    border-radius: 50%;
  }
}



@keyframes spinner-grow {
  0% {
    opacity: 0;
    transform: scale(0);
  }
  50% {
    opacity: 1;
  }
  100% {
    opacity: 0;
    transform: scale(1);
  }
}

.spinner-grow {
  position: relative;
  display: inline-block;
  width: 2rem;
  height: 2rem;
  overflow: hidden;
  text-indent: -999em;
  background-color: currentColor;
  border-radius: 50%;
  animation-name: spinner-grow;
  animation-duration: .75s;
  animation-timing-function: linear;
  animation-iteration-count: infinite;
}