[css-fonts] @font-palette-values rule has no object model

#1655

css-fonts-4/Overview.bs

@@ -3763,6 +3763,22 @@ of <i title="feature_value_block">feature value block</i>.  The <code>get</code>
 method always returns a sequence of values, even if the sequence only contains
 a single value.
 
+<h3 id="om-fontpalettevalues">
+The <code id="cssfontpalettevaluesrule2">CSSFontPaletteValuesRule</code> interface</h3>
+<pre class='idl'>partial interface CSSRule {
+
+  const unsigned short FONT_PALETTE_VALUES_RULE = 15;
+}
+
+interface CSSFontPaletteValuesRule : CSSRule {
+  maplike&lt;unsigned long, (CSSOMString or CSSOMRGBColor)>;
+  attribute CSSOMString fontFamily;
+  attribute CSSOMString basePalette;
+}</pre>
+
+If the value of the 'setlike' functions is a CSSOMString, it is parsed as a solid color (e.g. using the <code>rgb()</code> syntax). If it refers to anything other than a solid color, the call is ignored or returns <code>undefined</code>.
+
+The <code>fontFamily</code> and <code>basePalette</code> interfaces are parsed according to the appropriate CSS property syntax.
 
 <h2 id="platform-props-to-css" class="no-num">
 Appendix A: Mapping platform font properties to CSS properties</h2>