diff --git a/ui/src/components/comment-form.tsx b/ui/src/components/comment-form.tsx
index d6641a79fc7..591bbf1b21c 100644
--- a/ui/src/components/comment-form.tsx
+++ b/ui/src/components/comment-form.tsx
@@ -138,7 +138,7 @@ export class CommentForm extends Component<CommentFormProps, CommentFormState> {
               />
               {this.state.previewMode && (
                 <div
-                  className="md-div"
+                  className="card card-body md-div"
                   dangerouslySetInnerHTML={mdToHtml(
                     this.state.commentForm.content
                   )}
diff --git a/ui/src/components/post-form.tsx b/ui/src/components/post-form.tsx
index d424538bdf7..6840c2d48ba 100644
--- a/ui/src/components/post-form.tsx
+++ b/ui/src/components/post-form.tsx
@@ -284,7 +284,7 @@ export class PostForm extends Component<PostFormProps, PostFormState> {
               />
               {this.state.previewMode && (
                 <div
-                  className="md-div"
+                  className="card card-body md-div"
                   dangerouslySetInnerHTML={mdToHtml(this.state.postForm.body)}
                 />
               )}
diff --git a/ui/src/components/private-message-form.tsx b/ui/src/components/private-message-form.tsx
index 7667f5a11f4..6ad7de779a5 100644
--- a/ui/src/components/private-message-form.tsx
+++ b/ui/src/components/private-message-form.tsx
@@ -154,7 +154,7 @@ export class PrivateMessageForm extends Component<
               />
               {this.state.previewMode && (
                 <div
-                  className="md-div"
+                  className="card card-body md-div"
                   dangerouslySetInnerHTML={mdToHtml(
                     this.state.privateMessageForm.content
                   )}