Style comments from moderators in light blue, and admins in light green. Also puts text after the author's name (there should be something for colorblind people, not sure what form it should take though).

lms/static/sass/_discussion.scss

@@ -385,6 +385,14 @@ $tag-text-color: #5b614f;
           color: #dea03e;
         }
       }
+
+      .author-moderator:after{
+        content: " (moderator)"
+      }
+
+      .author-administrator:after{
+        content: " (administrator)"
+      }
     }
 
     .discussion-content {
@@ -410,6 +418,13 @@ $tag-text-color: #5b614f;
       }
     }
 
+    // Role based styles
+    .role-moderator{
+      background-color: #eafcfc;
+    }
+    .role-administrator{
+      background-color: #eafcea;
+    }
     //COMMENT STYLES
     .comments {
       overflow: hidden;

lms/templates/discussion/mustache/_content.mustache

@@ -1,5 +1,5 @@
-<div class="discussion-content local">
-  <div class="discussion-content-wrapper{{#content.roles}} role-{{name}}{{/content.roles}}">
+<div class="discussion-content local{{#content.roles}} role-{{name}}{{/content.roles}}">
+  <div class="discussion-content-wrapper">
     <div class="discussion-votes">
       <a class="discussion-vote discussion-vote-up" href="javascript:void(0)" value="up">&#9650;</a>
       <div class="discussion-votes-point">{{content.votes.point}}</div>
@@ -34,7 +34,7 @@
               anonymous
             {{/content.anonymous}}
             {{^content.anonymous}}
-              <a href="{{##url_for_user}}{{content.user_id}}{{/url_for_user}}">{{content.username}}</a>
+              <a href="{{##url_for_user}}{{content.user_id}}{{/url_for_user}}" class="{{#content.roles}}author-{{name}} {{/content.roles}}">{{content.username}}</a>
             {{/content.anonymous}}
           </div>
           <div class="show-comments-wrapper">