如何在悬停div时更改跨度样式？

<div class="container">
  <span class="span1">这是一个跨度</span>
</div>

.container {
  position: relative;
  width: 200px;
  height: 200px;
  background-color: #f0f0f0;
}

.span1 {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 16px;
  color: #000;
}

.span1:hover {
  font-size: 20px;
  color: #ff0000;
}