[css-color-4] allow device-cmyk as well as dash-ident in @color-profile

Author: svgeesus

css-color-4/Overview.bs

@@ -2429,11 +2429,13 @@ Specifying a color profile: the ''@color-profile'' at-rule</h3>
 	It's defined as:
 
 	<pre class='prod'>
-	@color-profile = @color-profile <<dashed-ident>> { <<declaration-list>> }
+	@color-profile = @color-profile [<<dashed-ident>> | ''device-cmyk''] { <<declaration-list>> }
 	</pre>
 
 	The <<dashed-ident>> gives the <a>color profile's</a> name,
 	by which it will be used in a CSS stylesheet.
+	Alternatively, the ''device-cmyk'' keyword means that this color profile
+	will be used to resolve colors specified in ''device-cmyk''.
 	<!-- All of the predefined colorspace keywords
 	(''srgb'', ''display-p3'', ''a98-rgb'', ''prophoto-rgb'', ''rec2020'')
 	are excluded from this <<custom-ident>>,
@@ -2979,7 +2981,7 @@ Simple alpha compositing</h3>
 <h2 id="sample">
 Default Style Rules</h2>
 
-	The following stylesheet is informative, not normative.  This style sheet could be used by an implementation as part of its default styling of HTML4, XHTML1, XHTML1.1, XHTML Basic, and other XHTML Family documents.
+	The following stylesheet is informative, not normative.  This style sheet could be used by an implementation as part of its default styling of HTML4, HTML5, XHTML1, XHTML1.1, XHTML Basic, and other XHTML Family documents.
 
 	<pre class="lang-css">
 	html {
@@ -2989,6 +2991,11 @@ Default Style Rules</h2>
 	/* traditional desktop user agent colors for hyperlinks */
 	:link { color: blue; }
 	:visited { color: purple; }
+
+	/* a reasonable, conservative default for device-cmyk */
+	@color-profile device-cmyk {
+		src: url('https://drafts.csswg.org/css-color-4/ICCprofiles/Coated_Fogra39L_VIGC_300.icc');
+	}
 	</pre>
 
 	The default background of the root element must be ''transparent''.