[css-fonts-4] Add left and right to font-style property, #9392

Author: svgeesus

css-fonts-4/Overview.bs

@@ -1150,7 +1150,7 @@ Font style: the 'font-style!!property' property</h3>
 
 	<pre class="propdef">
 	Name: font-style
-	Value: normal | italic | oblique <<angle [-90deg,90deg]>>?
+	Value: normal | italic | left | right | oblique <<angle [-90deg,90deg]>>?
 	Initial: normal
 	Applies to: all elements and text
 	Inherited: yes
@@ -1207,6 +1207,21 @@ Font style: the 'font-style!!property' property</h3>
 	    <dd>
 	        Matches against a font that is labeled as an italic face,
 	        or an oblique face if one does not exist.
+			The angle and direction of slant is unspecified.
+
+		<dt><dfn>left</dfn></dt>
+		<dd>
+			Matches against a font that is labeled as an italic face,
+			with a positive (clockwise) slant;
+			or an oblique face with positive slant, if one does not exist.
+		</dd>
+
+		<dt><dfn>right</dfn></dt>
+		<dd>
+			Matches against a font that is labeled as an italic face,
+			with a negative (counter-clockwise) slant;
+			or an oblique face with negative slant, if one does not exist.
+		</dd>
 
 	    <dt><dfn>oblique <<angle [-90deg,90deg]>>?</dfn>
 	    <dd>
@@ -1224,6 +1239,13 @@ Font style: the 'font-style!!property' property</h3>
 			a synthetic oblique face will be generated.
 	</dl>
 
+	<figure>
+		<img src="./images/contra-italic.png" alt="negative slant">
+		<figcaption>An italic face with negative slant. 
+			The font is Mf Autumn Breeze, 
+			by Misti Hammers.</figcaption>
+	</figure>
+
 	A font family might contain no italic or oblique faces,
 	only an italic face and no oblique,
 	only an oblique face and no italic,