diff --git a/Attributes.md b/Attributes.md
index 5d48aba..0e83a4f 100644
--- a/Attributes.md
+++ b/Attributes.md
@@ -37,6 +37,7 @@ Following labels are used for advanced configuration:
 * `hidePromotedAttributes`
 * `hideChildrenOverview`
 * `readOnly` - editor is in read only mode. Works only for text notes. See some use cases [here](https://github.com/zadam/trilium/issues/371).
+* `cssClass` - value of this label is then added as CSS class to the node representing given note in the tree. This can be useful for advanced [[theming|themes]].
 
 ## Relations
 Relation is a kind of link between two notes.