Bootstrap 4 - Responsive cards in card-columns

Bootstrap 4 (4.0.0-alpha.2) uses the css property column-count in the card-columns class to define how many columns of cards would be displayed inside the div element.
But this property has only two values:

• The default value 1 for small screens (max-width: 34em)
• The value 3 for all other sizes (min-width: 34em)

Here's how it is implemented in bootstrap.min.css :

@media (min-width: 34em) {
    .card-columns {
        -webkit-column-count:3;
        -moz-column-count:3;
        column-count:3;
        ⋮
    }
    ⋮
}

To make the card stacking responsive, you can add the following media queries to your css file and modify the values for min-width as per your requirements :

@media (min-width: 34em) {
    .card-columns {
        -webkit-column-count: 2;
        -moz-column-count: 2;
        column-count: 2;
    }
}

@media (min-width: 48em) {
    .card-columns {
        -webkit-column-count: 3;
        -moz-column-count: 3;
        column-count: 3;
    }
}

@media (min-width: 62em) {
    .card-columns {
        -webkit-column-count: 4;
        -moz-column-count: 4;
        column-count: 4;
    }
}

@media (min-width: 75em) {
    .card-columns {
        -webkit-column-count: 5;
        -moz-column-count: 5;
        column-count: 5;
    }
}

Update 2019 - Bootstrap 4

You can simply use the SASS mixin to change the number of cards across in each breakpoint / grid tier.

.card-columns {
  @include media-breakpoint-only(xl) {
    column-count: 5;
  }
  @include media-breakpoint-only(lg) {
    column-count: 4;
  }
  @include media-breakpoint-only(md) {
    column-count: 3;
  }
  @include media-breakpoint-only(sm) {
    column-count: 2;
  }
}

SASS Demo: http://www.codeply.com/go/FPBCQ7sOjX

Or, CSS only like this...

@media (min-width: 576px) {
    .card-columns {
        column-count: 2;
    }
}

@media (min-width: 768px) {
    .card-columns {
        column-count: 3;
    }
}

@media (min-width: 992px) {
    .card-columns {
        column-count: 4;
    }
}

@media (min-width: 1200px) {
    .card-columns {
        column-count: 5;
    }
}

CSS-only Demo: https://www.codeply.com/go/FIqYTyyWWZ