distinguish overlapping comments

app/components/SimpleEditor/panes/Comments/CommentsProvider.js

@@ -135,12 +135,12 @@ class CommentsProvider extends TocProvider {
   //
   changeActiveColor (id) {
     const commentElement = this.selectCommentElement(id)
-    if (commentElement) commentElement[0].style.borderBottom = '2px solid red'
+    commentElement[0].style.backgroundColor = '#eafaf0'
   }
 
   revertActiveColor (id) {
     const commentElement = this.selectCommentElement(id)
-    if (commentElement[0]) commentElement[0].style.borderBottom = '2px solid #228b46'
+    if (commentElement[0]) commentElement[0].removeAttribute('style')
   }
 
   selectCommentElement (id) {