grunt

dist/css/bootstrap.css

@@ -4027,76 +4027,71 @@ input[type="button"].btn-block {
   border-radius: 0 0 .25rem .25rem;
 }
 
-.card-deck {
+@media (min-width: 34em) {
+  .card-deck {
     display: table;
     table-layout: fixed;
     border-spacing: 1.25rem 0;
-}
-
-.card-deck .card {
+  }
+  .card-deck .card {
     display: table-cell;
     width: 1%;
     vertical-align: top;
-}
-
-.card-deck-wrapper {
+  }
+  .card-deck-wrapper {
     margin-right: -1.25rem;
     margin-left: -1.25rem;
+  }
 }
 
-.card-group {
+@media (min-width: 34em) {
+  .card-group {
     display: table;
     width: 100%;
     table-layout: fixed;
-}
-
-.card-group .card {
+  }
+  .card-group .card {
     display: table-cell;
     vertical-align: top;
-}
-
-.card-group .card + .card {
+  }
+  .card-group .card + .card {
     margin-left: 0;
     border-left: 0;
-}
-
-.card-group .card:first-child .card-img-top {
+  }
+  .card-group .card:first-child .card-img-top {
     border-top-right-radius: 0;
-}
-
-.card-group .card:first-child .card-img-bottom {
+  }
+  .card-group .card:first-child .card-img-bottom {
     border-bottom-right-radius: 0;
-}
-
-.card-group .card:last-child .card-img-top {
+  }
+  .card-group .card:last-child .card-img-top {
     border-top-left-radius: 0;
-}
-
-.card-group .card:last-child .card-img-bottom {
+  }
+  .card-group .card:last-child .card-img-bottom {
     border-bottom-left-radius: 0;
-}
-
-.card-group .card:not(:first-child):not(:last-child) {
+  }
+  .card-group .card:not(:first-child):not(:last-child) {
     border-radius: 0;
-}
-
-.card-group .card:not(:first-child):not(:last-child) .card-img-top,
-.card-group .card:not(:first-child):not(:last-child) .card-img-bottom {
+  }
+  .card-group .card:not(:first-child):not(:last-child) .card-img-top,
+  .card-group .card:not(:first-child):not(:last-child) .card-img-bottom {
     border-radius: 0;
+  }
 }
 
-.card-columns {
+@media (min-width: 34em) {
+  .card-columns {
     -webkit-column-count: 3;
        -moz-column-count: 3;
             column-count: 3;
     -webkit-column-gap: 1.25rem;
        -moz-column-gap: 1.25rem;
             column-gap: 1.25rem;
-}
-
-.card-columns .card {
+  }
+  .card-columns .card {
     display: inline-block;
     width: 100%;
+  }
 }
 
 .breadcrumb {

docs/dist/css/bootstrap.css

@@ -4027,76 +4027,71 @@ input[type="button"].btn-block {
   border-radius: 0 0 .25rem .25rem;
 }
 
-.card-deck {
+@media (min-width: 34em) {
+  .card-deck {
     display: table;
     table-layout: fixed;
     border-spacing: 1.25rem 0;
-}
-
-.card-deck .card {
+  }
+  .card-deck .card {
     display: table-cell;
     width: 1%;
     vertical-align: top;
-}
-
-.card-deck-wrapper {
+  }
+  .card-deck-wrapper {
     margin-right: -1.25rem;
     margin-left: -1.25rem;
+  }
 }
 
-.card-group {
+@media (min-width: 34em) {
+  .card-group {
     display: table;
     width: 100%;
     table-layout: fixed;
-}
-
-.card-group .card {
+  }
+  .card-group .card {
     display: table-cell;
     vertical-align: top;
-}
-
-.card-group .card + .card {
+  }
+  .card-group .card + .card {
     margin-left: 0;
     border-left: 0;
-}
-
-.card-group .card:first-child .card-img-top {
+  }
+  .card-group .card:first-child .card-img-top {
     border-top-right-radius: 0;
-}
-
-.card-group .card:first-child .card-img-bottom {
+  }
+  .card-group .card:first-child .card-img-bottom {
     border-bottom-right-radius: 0;
-}
-
-.card-group .card:last-child .card-img-top {
+  }
+  .card-group .card:last-child .card-img-top {
     border-top-left-radius: 0;
-}
-
-.card-group .card:last-child .card-img-bottom {
+  }
+  .card-group .card:last-child .card-img-bottom {
     border-bottom-left-radius: 0;
-}
-
-.card-group .card:not(:first-child):not(:last-child) {
+  }
+  .card-group .card:not(:first-child):not(:last-child) {
     border-radius: 0;
-}
-
-.card-group .card:not(:first-child):not(:last-child) .card-img-top,
-.card-group .card:not(:first-child):not(:last-child) .card-img-bottom {
+  }
+  .card-group .card:not(:first-child):not(:last-child) .card-img-top,
+  .card-group .card:not(:first-child):not(:last-child) .card-img-bottom {
     border-radius: 0;
+  }
 }
 
-.card-columns {
+@media (min-width: 34em) {
+  .card-columns {
     -webkit-column-count: 3;
        -moz-column-count: 3;
             column-count: 3;
     -webkit-column-gap: 1.25rem;
        -moz-column-gap: 1.25rem;
             column-gap: 1.25rem;
-}
-
-.card-columns .card {
+  }
+  .card-columns .card {
     display: inline-block;
     width: 100%;
+  }
 }
 
 .breadcrumb {