[css-values-4] Define minimum 32 terms/args/nesting in calc(). w3c#3462

Author: fantasai

css-values-4/Overview.bs

@@ -4127,11 +4127,13 @@ Syntax</h3>
 	on what their <<calc-sum>> arguments can contain.
 	Check the definitions of the individual functions for details.
 
-	UAs must support [=calculations=] of at least 20 <<calc-value>> terms.
-	If a [=calculation=] contains more than the supported number of terms,
+	UAs must support [=calculations=] of at least 32 <<calc-value>> terms
+	and at least 32 levels of nesting (parentheses and/or functions).
+	For functions that support an arbitrary number of arguments (such as ''min()''),
+	it must also support at least 32 arguments.
+	If a [=calculation=] contains more than the supported number of terms, arguments, or nesting
 	it must be treated as if it were invalid.
 
-
 <h3 id='calc-type-checking'>
 Type Checking</h3>