diff --git a/public/react/src/modules/courses/exercise/Exercisetablesmubu.js b/public/react/src/modules/courses/exercise/Exercisetablesmubu.js
index 92cfa30b7..6037254fe 100644
--- a/public/react/src/modules/courses/exercise/Exercisetablesmubu.js
+++ b/public/react/src/modules/courses/exercise/Exercisetablesmubu.js
@@ -155,6 +155,9 @@ class Exercisetablesmubus extends Component {
           .Exermubu .ant-table-tbody > tr:nth-last-child(1) > td{
 					  border:1px solid transparent;
           }
+		  .Exermubu .editormd-html-preview, .Exermubu .editormd-preview-container {
+			  background: transparent;
+		  }
 			`}
 				</style>
 				{datas===undefined?"":<Table