Fixed double border on cards with nav tabs (#2477)

build/scss/_cards.scss

@@ -2,6 +2,15 @@
 // Component: Cards
 //
 
+// Color variants
+@each $name, $color in $theme-colors {
+  @include cards-variant($name, $color);
+}
+
+@each $name, $color in $colors {
+  @include cards-variant($name, $color);
+}
+
 .card {
   @include box-shadow($card-shadow);
   margin-bottom: map-get($spacers, 3);
@@ -401,16 +410,6 @@ html.maximized-card {
   max-width: 200px;
 }
 
-// Color variants
-@each $name, $color in $theme-colors {
-  @include cards-variant($name, $color);
-}
-
-@each $name, $color in $colors {
-  @include cards-variant($name, $color);
-}
-
-
 // Nav Tabs override
 .card-default {
   .nav-item {