_flex.scss in foundation-rails-6.3.1.0

- old
+ new

@@ -15,9 +15,15 @@
     .align-self-#{$vdir} {
       @include flex-align-self($y: $vdir);
     }
   }
 
+  // Central alignment of content
+  .align-center-middle {
+    @include flex-align($x: center, $y: middle);
+    align-content: center;
+  }
+
   // Source ordering
   @include -zf-each-breakpoint {
     @for $i from 1 through 6 {
       .#{$-zf-size}-order-#{$i} {
         @include flex-order($i);