.flex{display: flex;}
.flex-row{flex-direction: row;}
.flex-row.reverse{flex-direction: row-reverse;}
.flex-column{flex-direction: column;}
.flex-column.reverse{flex-direction: column-reverse;}

.flex-row > div,
.flex-row.reverse > div,
.flex-column > div,
.flex-column.reverse > div{flex: 1;}


@media only screen and (max-width: 641px) {
    .flex-row{flex-direction: column;}
    .flex-row.reverse{flex-direction: column-reverse;}
}


.justify-content-center{
    justify-content: center;
}
.align-items-center{
    align-items: center;
}