CSS设置元素垂直居中的几种方法

.center1 {
    width: 200px;
    height: 200px;
    position: absolute;
    left: 50%;
    top: 50%;
    margin-left: -100px;
    margin-top: -100px;
}

.center2 {
    position: absolute;
    left: 0;
    top: 0;
    right: 0;
    bottom: 0;
    margin: auto;
}

.center3 {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
}

.center4 {
    display: flex;
    align-items: center;
    justify-content: center;
}

.center5 {
    display: table-cell;
    vertical-align: middle;
    text-align: center; 
}