body {
    background-color: black;
}

.center {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
}

.row {
    display: flex;
}

.column {
    flex: 50%;
    padding: 5px;
}

a.button {
    display: inline-block;
    padding: 0.35em 1.2em;
    border: 0.1em solid #FFFFFF;
    margin: 0 0.3em 0.3em 0;
    border-radius: 0.12em;
    box-sizing: border-box;
    text-decoration: none;
    font-family: 'Roboto', sans-serif;
    font-size: 2em;
    font-weight: 500;
    color: #FFFFFF;
    text-align: center;
    transition: all 0.2s;
    min-width: 15em;
    min-height: 2.5em;
}

a.button:hover {
    color: #000000;
    background-color: #FFFFFF;
}

@media all and (max-width:30em) {
    a.button {
        display: block;
        margin: 0.4em auto;
    }

    div.center {
        flex-direction: row;
    }
}