diff --git a/css-color-5/Overview.bs b/css-color-5/Overview.bs
index bd35dc9df4c..14a8f6945c7 100644
--- a/css-color-5/Overview.bs
+++ b/css-color-5/Overview.bs
@@ -1811,8 +1811,7 @@ Relative alpha colors refer to an origin color, and only change the alpha channe
 The grammar of the ''alpha()'' function, new in this level, is as follows:
 
 <pre class='prod'>
-<dfn>alpha()</dfn> = alpha([from <<color>>]
-					[ / [<<alpha-value>> | none] ]? )
+<dfn>alpha()</dfn> = alpha(from <<color>> / [<<alpha-value>> | none])
 </pre>