求star

方法一 Flex 布局#

.son {
  background-color: red;
  width: 100px;
  height: 100px;
}
.father {
  width: 500px;
  height: 500px;
  background-color: skyblue;
  display: flex;
  justify-content: center;
  align-items: center;
}

方法二 子绝父相 +transform: translate(-50%,-50%)#

.father {
  background-color: skyblue;
  width: 500px;
  height: 500px;
  position: relative;
}
.son {
  background-color: red;
  width: 100px;
  height: 100px;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

方法三 子绝父相 + margin:auto#

.father {
  background-color: skyblue;
  width: 500px;
  height: 500px;
  position: relative;
}
.son {
  background-color: red;
  width: 100px;
  height: 100px;
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  margin: auto;
}

方法四 table 布局#

.father {
            width: 300px;
            padding: 100px;
            vertical-align: middle;
            display: table-cell;
            background-color: pink;
        }

        .son {
            height: 100px;
            background-color: skyblue;
        }