.buttonBox-outerDiv {
    width: 100%;
    height: 100%;
    pointer-events: all;
    border-radius: inherit;
    display:table;
}

.buttonBox-mainButton {
    width: 100%;
    height: 100%;
    border-radius: inherit;
    display:table-cell;
    vertical-align: middle;
    text-align: center;
}