纯CSS悬停在div上隐藏内容，然后显示新文本

<div class="container">
  <div class="hidden-content">隐藏的内容</div>
  <div class="new-text">新文本</div>
</div>

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

.hidden-content {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: #f0f0f0;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.new-text {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: #000;
  font-weight: bold;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.container:hover .hidden-content {
  opacity: 1;
}

.container:hover .new-text {
  opacity: 1;
}