diff --git a/scss/_card.scss b/scss/_card.scss
index 295d6afcf9df..48ec3bb6b84f 100644
--- a/scss/_card.scss
+++ b/scss/_card.scss
@@ -156,6 +156,7 @@
 
     .card {
       display: flex;
+      // Flexbugs `#4`:https://github.com/philipwalton/flexbugs#4-flex-shorthand-declarations-with-unitless-flex-basis-values-are-ignored
       flex: 1 0 0%;
       flex-direction: column;
       margin-right: $card-deck-margin;
@@ -182,6 +183,7 @@
     flex-flow: row wrap;
 
     .card {
+      // Flexbugs `#4`:https://github.com/philipwalton/flexbugs#4-flex-shorthand-declarations-with-unitless-flex-basis-values-are-ignored
       flex: 1 0 0%;
       margin-bottom: 0;