Card columns can also be extended and customized with some additional code. Shown below is an extension of the .card-columns class using the same CSS we use—CSS columns— to generate a set of responsive tiers for changing the number of columns.
.card-columns {
@include media-breakpoint-only(lg) {
column-count: 4;
}
@include media-breakpoint-only(xl) {
column-count: 5;
}
}