如何悬停在子元素上，但将背景颜色拉伸到父元素上？

<div class="parent">
  <div class="child">子元素</div>
</div>

.parent {
  position: relative;
  width: 300px;
  height: 200px;
  background-color: #f0f0f0;
}

.child {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  padding: 10px;
  background-color: #fff;
  z-index: 1;
}

.child:before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: #f0f0f0;
  z-index: -1;
}

.child:hover:before {
  background-color: #ff0000;
}