居中

水平居中

1.text-align

.parent {
  text-align: center;
}

.son {
  display: inline-block;
}

2.margin

.son {
  margin: 0 auto;
}

3.flex

.parent {
  display: flex;
  justify-content: center;
}

4.grid

.parent {
  display: grid;
  justify-content: center;
}

/* 或者 */
.parent {
  display: grid;
}

.son {
  justify-self: center;
}

5.绝对定位

.parent {
  position: relative;
}

.son {
  position: absolute;
  left: 50%;
  transform: translate(-50%, 0);
}

6.table

.parent {
  display: table;
  text-align: center;
}

.son {
  display: inline-block;
}

垂直居中

1.flex 布局

.parent {
  display: flex;
  align-items: center;
}

2.gird 布局

.parent {
  display: grid;
  align-items: center;
}

3.绝对定位

.parent {
  position: relative;
}

.son {
  position: absolute;
  top: 0;
  bottom: 0;
  margin: auto 0;
}

.son {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
}

4.vertical-align + line-height

.parent {
  line-height: 200px;
}

.son {
  display: inline-block;
  vertical-align: middle;
}

水平垂直居中

1.flex

.parent {
  display: flex;
  justify-content: center;
  align-items: center;
}

2.grid

.parent {
  display: grid;
  justify-content: center;
  align-items: center;
}

/* OR */

.parent {
  display: grid;
}

.son {
  justify-self: center;
  align-self: center;
}

3.绝对定位

.parent {
  position: relative;
}

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

.son {
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
  margin: auto;
}