[Update]Redmine #719 : background color to empty variation

wp-content/themes/nap/assets/css/main.css

@@ -2144,6 +2144,7 @@ label.chevron.bottom::first-letter {
 }
 .product-list article .article-bg{
   opacity: 0.1;
+  background-color: rgb(153, 153, 153);
 }
 .panel .product-list article figure{
   height: 180px;