[css-fonts-4] better introduce color font support

Author: svgeesus

css-fonts-4/Overview.bs

@@ -5438,7 +5438,7 @@ at an unspecified time during the animation.
 <h2 id="color-font-support">
 Color Font Support</h2>
 
-Color fonts allow for font files to describe
+Color fonts allow for font files to describe,
 not just the contours describing the edges of glyphs,
 but also the colors present inside the glyphs.
 
@@ -5447,6 +5447,19 @@ but also the colors present inside the glyphs.
 	<figcaption>Multicolore, by Ivan Filipov</figcaption>
 </figure>
 
+For some uses, such as emoji,
+having the colors fixed in the font is appropriate.
+For others, there is a need to control the colors used from a stylesheet.
+
+CSS provides two ways to do this.
+The 'font-palette' property allows selecting
+one of several different palettes
+contained in the font.
+The ''@font-palette-values'' rule allows overriding
+one or more colors from within a palette
+or even
+the creation of an entirely different palette.
+
 <h3 id="font-palette-prop">
 Controlling Color Font Palettes: The 'font-palette' property</h3>