[css-fonts-4] First pass at named palette entries for w3c#1125

Author: svgeesus

css-fonts-4/Overview.bs

@@ -4039,18 +4039,48 @@ It has the following syntax:
 
 The ''@font-palette-values'' rule accepts the descriptors defined in this specification.
 
-<div class="example">
-	Modify Handover Sans's color palette
+	The '@font-palette-values/override-color' descriptor takes
+	a comma-separated list
+	of palette index entries and colors.
 
-	<pre>
-	@font-palette-values Augusta {
-		font-family: Handover Sans;
-		base-palette: 3;
-		color-1: rgb(43, 12, 9);
-		color-3: var(--highlight);
-	}
-	</pre>
-</div>
+	<div class="example">
+		Modify Handover Sans's color palette
+
+		<pre>
+		@font-palette-values Augusta {
+			font-family: Handover Sans;
+			base-palette: 3;
+			override-color:
+				1 rgb(43, 12, 9),
+				3 var(--highlight);
+		}
+		</pre>
+	</div>
+
+	The ''@font-palette-values/base-palette'' descriptor accepts either
+	a (zero-based) numerical palette index, or
+	a string, which corresponds to a named palette.
+
+	Palette index entries
+	in the ''@font-palette-values/override-color'' descriptor
+	are either a (zero-based) palette index entry, or
+	a string, which corresponds to a named palette entry
+	in the selected palette.
+
+	<div class="example">
+			Modify Banner Flag's color palette
+
+			<pre>
+			@font-palette-values Festival {
+				font-family: Banner Flag;
+				base-palette: 'Dark';
+				override-color:
+					'Outline' rgb(123, 64, 27),
+					'Base Glyph' currentColor,
+					'Glints' var(--highlight);
+			}
+			</pre>
+		</div>
 
 The presence of a particular descriptor within in ''@font-palette-values'' has semantic meaning;
 missing descriptors are not filled in with default values.