diff --git a/css-syntax-3/Overview.bs b/css-syntax-3/Overview.bs
index 49523f13efac..82dba5af8943 100644
--- a/css-syntax-3/Overview.bs
+++ b/css-syntax-3/Overview.bs
@@ -137,8 +137,9 @@ Description of CSS's Syntax</h2>
 	</div>
 
 	Property names and <a>at-rule</a> names are always <a>identifiers</a>,
-	which have to start with a letter or a hyphen followed by a letter,
-	and then can contain letters, numbers, hyphens, or underscores.
+	which have to start with an <a>identifier-start code point</a>, two hyphens,
+	or a hyphen followed by an identifier-start code point,
+	and then can contain zero or more <a>identifier code points</a>.
 	You can include any <a>code point</a> at all,
 	even ones that CSS uses in its syntax,
 	by <a>escaping</a> it.