.bars-container {
  display: flex;
  justify-content: center;
  align-items: flex-end;
  height: 30px;
  margin-top: 10px;
}

.bar {
  height: 20px;
  width: 5px;
  margin: 0 2px;
  background-color: #ccc;
  animation: bar 1s ease-in-out infinite;
}

.bar:nth-child(1) {
  animation-delay: 0.05s;
}

.bar:nth-child(2) {
  animation-delay: 0.1s;
}

.bar:nth-child(3) {
  animation-delay: 0.15s;
}

.bar:nth-child(4) {
  animation-delay: 0.2s;
}

.bar:nth-child(5) {
  animation-delay: 0.25s;
}

.bar:nth-child(6) {
  animation-delay: 0.3s;
}

.bar:nth-child(7) {
  animation-delay: 0.35s;
}

.bar:nth-child(8) {
  animation-delay: 0.4s;
}

.bar:nth-child(9) {
  animation-delay: 0.45s;
}

.bar:nth-child(10) {
  animation-delay: 0.5s;
}

@keyframes bar {
  0% {
    height: 20px;
  }
  50% {
    height: calc(20px + 30px * var(--height));
  }
  100% {
    height: 20px;
  }
}