<figure class="d-container">
  <div class="d-flex-vertical">
    <div class="d-flex-vertical-center">
    CSS Vertical centering is a sign of the apocalypse.
    </div>
  </div>
</figure>

* {
    margin: 0;
    padding: 0
}

li {
    list-style: none
}

* {
    box-sizing: border-box
}


body {
    font-size: 100%;
    line-height: 1.6
}

.d-container:first-child {
    margin-top: 0
}

.d-container {
    background: #f7f7f7;
    border-bottom: 1px solid #eee;
    margin: 2em auto;
    padding: 2em 5%;
    width: 100%
}

.d-container:after {
    clear: both;
    content: "";
    display: table
}

.d-container>h1 {
    color: #333;
    font-size: 2em;
    line-height: 1.2;
    margin: 0 0 .5em;
    text-align: center
}
.d-flex-vertical {
    -webkit-box-align: center;
    -webkit-align-items: center;
    -ms-flex-align: center;
    align-items: center;
    display: -webkit-box;
    display: -webkit-flex;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-pack: center;
    -webkit-justify-content: center;
    -ms-flex-pack: center;
    justify-content: center;
    min-height: 15em
}

.d-flex-vertical-center {
    display: -webkit-box;
    display: -webkit-flex;
    display: -ms-flexbox;
    display: flex;
    background: #fff;
    color: #333;
    padding: 2.5em;
    -webkit-box-flex: 0;
    -webkit-flex: 0 0 200px;
    -ms-flex: 0 0 200px;
    flex: 0 0 200px;
    border: 1px solid #ddd
}

@media all and (min-width: 30em) {
    .d-flex-vertical-center {
        -webkit-box-flex: 0;
        -webkit-flex: 0 0 400px;
        -ms-flex: 0 0 400px;
        flex: 0 0 400px
    }
}