add class for comma-separated list

templates/default-layout.lucius

@@ -115,10 +115,6 @@ ul {
   list-style-type: none;
 }
 
-.list--inline > li {
-  display: inline-block;
-}
-
 h1, h2, h3, h4, h5 {
   font-weight: 600;
 }
@@ -422,6 +418,22 @@ input[type="button"].btn-info:hover,
   line-height: 25px;
 }
 
+/* LIST MODIFIERS */
+.list--inline > li {
+  display: inline-block;
+}
+
+.list--comma-separated > li {
+
+  &::after {
+    content: ', ';
+  }
+
+  &:last-of-type::after {
+    content: none;
+  }
+}
+
 /* DEFINITION LIST */
 .deflist {
   display: grid;