<div class="wrapper">
  <div class="content">
    Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.
  </div>
</div>
.content {
  padding: 17px 0 17px 17px;
  width: 300px;
  height: 200px;
  overflow-y: scroll;
  mask-image: linear-gradient(to top, transparent, black),
    linear-gradient(to left, transparent 17px, black 17px);
  mask-size: 100% 20000px;
  mask-position: left bottom;
  -webkit-mask-image: linear-gradient(to top, transparent, black),
    linear-gradient(to left, transparent 17px, black 17px);
  -webkit-mask-size: 100% 20000px;
  -webkit-mask-position: left bottom;
  transition: mask-position 0.3s, -webkit-mask-position 0.3s;
}

.content:hover {
  -webkit-mask-position: left top;
}

@keyframes background {
  from {
    background: pink;
  }
  to {
    background: #c0d6ff;
  }
}

.wrapper {
  float: left;
  animation: background 5s infinite alternate;
}

// 17px should probably not be hardcoded but calculated as mentioned in https://stackoverflow.com/a/65665171/1008823

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