Music loader

  <div class="container">
    <section>
      <div class="music-loader">
        <div class="line line1"></div>
        <div class="line line2"></div>
        <div class="line line3"></div>
      </div>
    </section>
  </div>

body {
  background: black;
}

.container {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%,-50%);
}

section {
  width: 100%;
}

.music-loader {
  position: relative;
  width: 80px;
  height: 80px;
}

.line {
  width: 10px;
  position: absolute;
  border-radius: 5px;
  bottom: 0;
  background: linear-gradient(to bottom, purple, crimson);
}

.line1 {
  left: 0;
  animation: dance 0.5s ease alternate infinite;
}

.line2 {
  left: 20px;
  animation: dance 0.5s 0.2s ease alternate infinite;
}

.line3 {
  left: 40px;
  animation: dance 0.5s 0.4s ease alternate infinite;
}

@keyframes dance {
  0% {
    height: 0;
  }
  100% {
    height: 80%;
  }
}