.loader {
  width: 10em;
  height: 3em;
  display: flex;
  justify-content: space-around;
  align-items: center;
}

.line {
  width: 1em;
  height: 1em;
  position: relative;
  background-color: #000000; /* Black bars */
  outline: 3px solid #ffffff; /* Thick white outline */
  border-radius: 1em;
  animation-name: a;
  animation-duration: 2s;
  animation-iteration-count: infinite;
}

.l1 {
  animation-delay: 0.4s;
}

.l2 {
  animation-delay: 0.8s;
}

.l3 {
  animation-delay: 1.2s;
}

.l4 {
  animation-delay: 1.6s;
}

.l5 {
  animation-delay: 2s;
}

@keyframes a {
  0% {
    height: 1em;
  }
  50% {
    height: 3em;
    transform: translateY(-30%);
  }
  100% {
    height: 1em;
  }
}