怎么让一个div 水平垂直居中

自己在实际工作中经常用的两种是
1.flex布局

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

2.子绝父相

div.parent {
    position: relative;
}
div.child {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

还有两种了解过
3.grid布局

div.parent {
    display: grid;
}
div.child {
    justify-self: center;
    align-self: center;
}

4.vertical-align: middle;

div.parent {
    font-size: 0;
    text-align: center;
    &::before {
        content: "";
        display: inline-block;
        width: 0;
        height: 100%;
        vertical-align: middle;
    }
}
div.child{
    display: inline-block;
    vertical-align: middle;
}