* {
    box-sizing: border-box;
}

.item {
    width: 200px;
    height: 200px;
    margin: 50px auto;
    padding-top: 75px;
    background: White;
    text-align: center;
    color: dimgrey;
    font-size: 3em;
}

.box {
    width: 100vw;
    height: 100vh;
}

.box {
    display: -webkit-box;
    display: -ms-flexbox;
    display: -webkit-flex;
    display: flex;
    -webkit-box-align: center;
    -ms-flex-align: center;
    -webkit-align-items: center;
    align-items: center;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    -webkit-justify-content: center;
    justify-content: center;
    -webkit-flex-direction: column;
    -ms-flex-direction: column;
    flex-direction: column;
}