fix(card): inverted header links were not styled properly

When header link was inside an inverted cards group (not inside a single card!), it was not styled properly.
This PR now adds the same logic as for single card making link header visible again

Author: lubber-de

src/definitions/views/card.less

@@ -929,6 +929,13 @@ each(@colors,{
   .ui.inverted.card > .content > .header {
     color: @invertedHeaderColor;
   }
+  .ui.inverted.cards > .card > .content > a.header,
+  .ui.inverted.card > .content > a.header {
+    color: @invertedHeaderLinkColor;
+    &:hover {
+      color: @invertedHeaderLinkHoverColor;
+    }
+  }
 
   /* Description */
   .ui.inverted.cards > .card > .content > .description,

src/themes/default/views/card.variables

@@ -227,6 +227,8 @@
 @invertedBackground: @black;
 @invertedContentDivider: @borderWidth solid rgba(255, 255, 255, 0.15);
 @invertedHeaderColor: @invertedTextColor;
+@invertedHeaderLinkColor: @invertedTextColor;
+@invertedHeaderLinkHoverColor: @linkHoverColor;
 @invertedDescriptionColor: @invertedMutedTextColor;
 @invertedMetaColor: @invertedLightTextColor;
 @invertedMetaLinkColor: @invertedLightTextColor;