CSS height 实例

<style>
  .height-demo {
    background-color: #e8e8e8;
    padding: 10px;
  }
  .height-item {
    background-color: #2196F3;
    border: 1px solid #000;
    color: white;
    font-size: 18px;
    font-weight: bold;
    text-align: center;
    padding: 10px;
    margin: 5px 0;
  }
  .height-fixed {
    height: 80px;
  }
  .height-auto {
    height: auto;
  }
</style>
<div class="height-demo">
  <div class="height-item height-fixed">固定高度 80px</div>
  <div class="height-item height-auto">自动高度（由内容决定）</div>