再次垂直水平居中 - flex+margin

by redky

HTML

<div class="box">
    <div class="s">hello</div>
</div>

CSS

.box {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    display: flex;
}

.s {
    margin: auto;
}