让一个元素水平垂直居中的方式

1. 定位+margin

<style>
*{
  margin: 0;
  padding: 0;
}
.father{
  width: 400px;
  height: 400px;
  border: 1px solid;
  position: relative;
}
.son{
  position: absolute;
  width: 200px;
  height: 200px;
  background-color: red;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  margin: auto;
}
</style>
<body>
<div class="father">
  <div class="son"></div>
</div>
<body>

2. 定位+transform

<style>
.father{
  width: 400px;
  height: 400px;
  border: 1px solid;
  position: relative;
}
.son{
  position: absolute;
  width: 200px;
  height: 200px;
  background-color: blue;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}
</style>
<body>
<div class="father">
  <div class="son"></div>
</div>
<body>

3. flex

<style>
.father{
  width: 400px;
  height: 400px;
  border: 1px solid;
  display: flex;
  align-item: center;
  justify-content: center;
}
.son{
  width: 200px;
  height: 200px;
  background-color: pink;
}
</style>
<body>
<div class="father">
  <div class="son"></div>
</div>
<body>

4. grid布局
5. table布局