<div class="loader">
  <div style="--i:0"></div>
  <div style="--i:1"></div>
  <div style="--i:2"></div>
  <div style="--i:3"></div>
  <div style="--i:4"></div>
</div>

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  background: #282828;
  min-height: 100vh;
}

.loader {
  display: flex;
  flex-direction: row;
}

.loader div {
  position: relative;
  width: 40px;
  height: 200px;
  margin: 20px;
  overflow: hidden;
  border-radius: 40px;
  background: linear-gradient(to bottom, rgba(0, 0, 0, 0.5));
  border: 2px solid #272727;
  box-shadow: -5px -5px 5px rgba(92, 92, 92, 0.1),
    10px 10px 10px rgba(0, 0, 0, 0.4), 
    inset -5px -5px 5px rgba(82, 82, 82, 0.2),
    inset 10px 10px 10px rgba(0, 0, 0, 0.4);
}

.loader div::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 10;
  border-radius: 40px;
  box-shadow: -5px -5px 5px rgba(92, 92, 92, 0.1),
    10px 10px 10px rgba(0, 0, 0, 0.4), inset -5px -5px 5px rgba(82, 82, 82, 0.2),
    inset 10px 10px 10px rgba(0, 0, 0, 0.4);
}

.loader div::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 36px;
  height: 36px;
  background: #343434;
  border-radius: 50%;
  box-shadow: inset -5px -5px 5px rgba(0, 0, 0, 0.2), 0 420px 0 400px #ffe700;
  animation: animate 2.5s ease-in-out infinite;
  transform: translateY(160px);
  animation-delay: calc(-0.5s * var(--i));
}

@keyframes animate {
  0% {
    transform: translateY(160px);
    filter: hue-rotate(180deg);
  }

  50% {
    transform: translateY(0px);
  }

  100% {
    transform: translateY(160px);
    filter: hue-rotate(0deg);
  }
}

/* https://www.youtube.com/watch?v=XGok4UIqu8E */