diff --git a/docs/guide/CSS.md b/docs/guide/CSS.md
index b0719e430..2eb20b6ea 100644
--- a/docs/guide/CSS.md
+++ b/docs/guide/CSS.md
@@ -62,7 +62,7 @@ You may be able to guess what some of the the other rules do. We will cover thos
 
 The DOM, or _Document Object Model_, is a term borrowed from the web world. Textual doesn't use documents but the term has stuck. In Textual CSS, the DOM is a an arrangement of widgets that forms a tree of sorts.
 
-Some widgets contain other widgets: for instance a list control widget will likely also have item widgets, or a dialog widget may contain button widgets. These _child_ widgets form the branches of the tree.
+Some widgets contain other widgets: for instance, a list control widget will likely also have item widgets, or a dialog widget may contain button widgets. These _child_ widgets form the branches of the tree.
 
 Let's look at a trivial Textual app.