Use <ident-token> instead of Identifier (#3075)

spec/at-rules/forward.md

@@ -17,12 +17,14 @@ The grammar for the `@forward` rule is as follows:
 
 <x><pre>
 **ForwardRule** ::= '@forward' QuotedString AsClause? (ShowClause | HideClause)?
-**AsClause**    ::= 'as' Identifier '*'
+**AsClause**    ::= 'as' [\<ident-token>][] '*'
 **ShowClause**  ::= 'show' MemberName (',' MemberName)*
 **HideClause**  ::= 'hide' MemberName (',' MemberName)*
-**MemberName**  ::= '$'? Identifier
+**MemberName**  ::= '$'? [\<ident-token>][]
 </pre></x>
 
+[\<ident-token>]: https://drafts.csswg.org/css-syntax-3/#ident-token-diagram
+
 `@forward` rules must be at the top level of the document, and must come before
 any rules other than `@charset` or `@use`. The `QuotedString`'s contents, known
 as the rule's *URL*, must be a [valid URL string][] (for non-[special][] base

spec/at-rules/function.md

@@ -8,9 +8,11 @@
 ## Syntax
 
 <x><pre>
-**FunctionRule** ::= '@function' Identifier ArgumentDeclaration '{' Statements '}'
+**FunctionRule** ::= '@function' [\<ident-token>][] ArgumentDeclaration '{' Statements '}'
 </pre></x>
 
+[\<ident-token>]: https://drafts.csswg.org/css-syntax-3/#ident-token-diagram
+
 No whitespace is allowed between the `Identifier` and the `ArgumentDeclaration`
 in `FunctionRule`.
 

spec/at-rules/mixin.md

@@ -17,9 +17,11 @@
 ### Syntax
 
 <x><pre>
-**MixinRule** ::= '@mixin' Identifier ArgumentDeclaration? '{' Statements '}'
+**MixinRule** ::= '@mixin' [\<ident-token>][] ArgumentDeclaration? '{' Statements '}'
 </pre></x>
 
+[\<ident-token>]: https://drafts.csswg.org/css-syntax-3/#ident-token-diagram
+
 No whitespace is allowed between the `Identifier` and the `ArgumentDeclaration`
 in `MixinRule`.
 

spec/at-rules/use.md

@@ -29,13 +29,15 @@ The grammar for the `@use` rule is as follows:
 
 <x><pre>
 **UseRule**         ::= '@use' QuotedString AsClause? WithClause?
-**AsClause**        ::= 'as' ('\*' | Identifier)
+**AsClause**        ::= 'as' ('\*' | [\<ident-token>][])
 **WithClause**      ::= 'with' '('
 &#32;                     KeywordArgument (',' KeywordArgument)\* ','?
 &#32;                   ')'
-**KeywordArgument** ::= '$' Identifier ':' Expression
+**KeywordArgument** ::= '$' [\<ident-token>][] ':' Expression
 </pre></x>
 
+[\<ident-token>]: https://drafts.csswg.org/css-syntax-3/#ident-token-diagram
+
 `@use` rules must be at the top level of the document, and must come before any
 rules other than `@charset` or `@forward`. The `QuotedString`'s contents, known
 as the rule's *URL*, must be a [valid URL string][] (for non-[special][] base

spec/modules.md

@@ -163,7 +163,7 @@ modules:
 
 <x><pre>
 **PublicIdentifier**     ::= [\<ident-token>][] that doesn't begin with '-' or '_'
-**NamespacedIdentifier** ::= Identifier | Identifier '.' PublicIdentifier
+**NamespacedIdentifier** ::= [\<ident-token>][] | [\<ident-token>][] '.' PublicIdentifier
 </pre></x>
 
 [\<ident-token>]: https://drafts.csswg.org/css-syntax-3/#ident-token-diagram

spec/syntax.md

@@ -99,7 +99,7 @@ No whitespace is allowed between components of an `InterpolatedIdentifier`.
 **PseudoSelector** ::= NormalPseudoSelector
                  | SelectorPseudo
                  | NthSelectorPseudo
-**NormalPseudoSelector** ::= ':' ':'? VendorPrefix? Identifier
+**NormalPseudoSelector** ::= ':' ':'? VendorPrefix? [\<ident-token>][]
 &#32;                        ('(' [\<declaration-value>] ')')?
 **SelectorPseudo** ::= SelectorPseudoName '(' Selector ')'
 **NthSelectorPseudo** ::= NthSelectorPseudoName '(' [\<an+b>] 'of'¹ Selector ')'
@@ -110,6 +110,7 @@ No whitespace is allowed between components of an `InterpolatedIdentifier`.
 
 [\<declaration-value>]: https://www.w3.org/TR/css-syntax-3/#typedef-declaration-value
 [\<an+b>]: https://www.w3.org/TR/css-syntax-3/#the-anb-type
+[\<ident-token>]: https://drafts.csswg.org/css-syntax-3/#ident-token-diagram
 
 1: The string `of` is matched case-insensitively. In addition, it must be parsed
    as an identifier.

spec/variables.md

@@ -14,11 +14,12 @@
 
 <x><pre>
 **Variable**            ::= PlainVariable | NamespacedVariable
-**PlainVariable**       ::= '$' Identifier
-**NamespacedVariable**  ::= Identifier '.$' [PublicIdentifier][]
+**PlainVariable**       ::= '$' [\<ident-token>][]
+**NamespacedVariable**  ::= [\<ident-token>][] '.$' [PublicIdentifier][]
 **VariableDeclaration** ::= Variable ':' Expression ('!global' | '!default')*
 </pre></x>
 
+[\<ident-token>]: https://drafts.csswg.org/css-syntax-3/#ident-token-diagram
 [PublicIdentifier]: modules.md#syntax
 
 No whitespace is allowed after the `$` in `PlainVariable` or before or after