VIP26/day17/css/2.盒子水平垂直居中.css

* {
    margin: 0;
    padding: 0;
}

html,body {
    height: 100%;
}
body {
    display: flex;
    justify-content: center;
    align-items: center;
}

#box {
    width: 200px;
    height: 200px;
    background: #00f;
}