Merge pull request #9 from ckeditor/t/ckeditor5/940

Docs: Fix nested editable styles in document editor sample.

sample/index.html

@@ -38,7 +38,7 @@
 		max-height: 500px;
 	}
 
-	.editable-container .ck-editor__editable {
+	.editable-container .document-editor__editable.ck-editor__editable {
 		min-height: 21cm;
 		padding: 2em;
 		border: 1px #D3D3D3 solid;