.center {
    margin: auto;
    padding: 0px;
    text-align: center;
}

.vertical-alignment {
    position: absolute;
    top: 50%;
    width: 100%;
    transform: translate(0%, -50%);
}

.box {
    border: 3px solid black;
    display: inline-block;
    padding: 10px;
}