Four methods vertically centered horizontally disposed css

Disclaimer: This article is a blogger original article, follow the CC 4.0 BY-SA copyright agreement, reproduced, please attach the original source link and this statement.

This link: https://blog.csdn.net/weixin_45734493/article/details/102513970

If you want a method that can be used around the elements of its float, flex, position

Block elements centered about margin 0 auto;

Inline elements parent element of text-align center

The vertical and horizontal center of it?

1.position

html part

<div class="center">test</div>

Elements known width and height, css portion

  .center {
    background: red;
    width: 100px;
    height: 100px;
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    margin: auto;
  } 

   /* or */

  .center {
    background: red;
    width: 100px;
    height: 100px;
    position: absolute;
    top: 50%;
    left: 50%;
    margin: -50px 0 0 -50px;
  } 

Unknown element width and height, css portion

  .center {
    color: red;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
  }

2.flex layout

html part

<div class="wrap">
  <div class="item">test</div>
</div>

css section

  .wrap {
    width: 100%;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  .item {
    color: red;
  }

3. The pseudo-class

html part

<div class="wrap">
  <div class="item">test</div>
</div>

css section

  .wrap {
    width: 100%;
    height: 100%;
    background-color: #009ef4;
    text-align: center;
    position: absolute;
    top: 0;
    left: 0;
  }

  .wrap:after {
    display: inline-block;
    content: '';
    width: 0;
    height: 100%;
    vertical-align: middle;
  }

  .item {
    color: red;
    display: inline-block;
    vertical-align: middle;
  }

4. Use the table

html part

  <div class="wrap">
    <div class="item">
      test
    </div>
  </div>

css section

  .wrap {
    width: 100%;
    height: 100vh;
    display: table;
  }

  .item {
    color: #F00;
    display: table-cell;
    vertical-align: middle;
    text-align: center;
  }