html,
body {
    width: 100%;
    height: 100%;
    margin: 0 auto;
    padding: 0;
    background-color: #222222;
    color: #ffffff;
}
.page {
    width: 100%;
    height: 100%;
    display: table;
}
.contents {
    display: table-cell;
    vertical-align: middle;
    text-align: center;
    -webkit-tap-highlight-color: transparent;
}
button {
    background-color: #42A6FF;
    border: none;
    border-radius: 0.3rem;
    color: white;
    font-size: 30px;
    font-weight: bold;
    padding: 0.7rem 1.5rem;
}
