diff --git a/framework/core/js/forum/src/components/notification.js b/framework/core/js/forum/src/components/notification.js
index 34541ee8f..ac2cf0791 100644
--- a/framework/core/js/forum/src/components/notification.js
+++ b/framework/core/js/forum/src/components/notification.js
@@ -2,12 +2,13 @@ import Component from 'flarum/component';
 import avatar from 'flarum/helpers/avatar';
 import icon from 'flarum/helpers/icon';
 import humanTime from 'flarum/helpers/human-time';
+import { dasherize } from 'flarum/utils/string';
 
 export default class Notification extends Component {
   view(args) {
     var notification = this.props.notification;
 
-    return m('div.notification.notification-'+notification.contentType(), {
+    return m('div.notification.notification-'+dasherize(notification.contentType()), {
       classNames: !notification.isRead() ? 'unread' : '',
       onclick: this.read.bind(this)
     }, m('a', {href: args.href, config: args.config}, [
diff --git a/framework/core/js/forum/src/components/post-activity.js b/framework/core/js/forum/src/components/post-activity.js
index 6c6b2a938..db71254af 100644
--- a/framework/core/js/forum/src/components/post-activity.js
+++ b/framework/core/js/forum/src/components/post-activity.js
@@ -2,13 +2,14 @@ import Post from 'flarum/components/post';
 import username from 'flarum/helpers/username';
 import icon from 'flarum/helpers/icon';
 import humanTime from 'flarum/utils/human-time';
+import { dasherize } from 'flarum/utils/string';
 
 export default class PostActivity extends Post {
   view(iconName, content, attrs) {
     var post = this.props.post;
 
     attrs = attrs || {};
-    attrs.className = 'post-activity post-'+post.contentType()+' '+(attrs.className || '');
+    attrs.className = 'post-activity post-'+dasherize(post.contentType())+' '+(attrs.className || '');
 
     return super.view([
       icon(iconName+' post-icon'),
diff --git a/framework/core/js/lib/utils/string.js b/framework/core/js/lib/utils/string.js
new file mode 100644
index 000000000..2fb5b2b65
--- /dev/null
+++ b/framework/core/js/lib/utils/string.js
@@ -0,0 +1,5 @@
+export function dasherize(string) {
+  return string.replace(/([A-Z])/g, function ($1) {
+    return '-' + $1.toLowerCase();
+  });
+}