[css-ruby-1][css-pseudo-4] Apply ruby-position to ::first-line per w3c#2998

Author: fantasai

css-pseudo-4/Overview.bs

@@ -195,6 +195,7 @@ Styling the First Line Pseudo-element</h4>
     <li>all background properties (see [[CSS3BG]])
     <li>any typesetting properties that apply to inline elements (see [[CSS3TEXT]])
     <li>all text decoration properties (see [[CSS3-TEXT-DECOR]])
+    <li>the 'ruby-position' property (see [[CSS-RUBY-1]])
     <li>any inline layout properties that apply to inline elements (see [[CSS-INLINE-3]])
     <li>any other properties defined to apply to ''::first-line''
         by their respective specifications
@@ -951,6 +952,9 @@ Changes</h2>
     <li>Added ''::marker'' to types allowed for {{CSSPseudoElement}} interface.
     <li>Clarified return value of {{pseudo()}}.
     <li>Added 'content', 'unicode-bidi', and 'direction' to properties allowed on ''::marker''.
+    <li>Added 'ruby-position' to properties allowed on ''::first-line'',
+    analogous with 'text-emphasis-position'.
+    (<a href="https://github.com/w3c/csswg-drafts/issues/2998">Issue 2998</a>)
   </ul>
 
   Changes since the <a href="https://www.w3.org/TR/2016/WD-css-pseudo-4-20160607/">7 June 2016 Working Draft</a> include:

css-ruby-1/Overview.bs

@@ -40,8 +40,9 @@ Module interactions</h3>
 	<p>This module extends the inline box model of CSS Level 2 [[!CSS2]]
 	to support ruby.
 
-	<p>None of the properties in this module apply to the <code>::first-line</code> or
-	<code>::first-letter</code> pseudo-elements.
+	<p>None of the properties in this module apply to the ''::first-line'' or
+	''::first-letter'' pseudo-elements,
+	except for 'ruby-position' which applies to ''::first-line''.
 
 <h3 id="values">
 Values</h3>
@@ -1570,6 +1571,8 @@ Changes since the 5 August 2014 WD</h3>
 	<li>Add section on <a href="#ruby-text-decoration">text decoration</a>.
 	<li>Defer the <css>right</css> and <css>left</css> values of 'ruby-position' to the next level.
 	<li>Change ruby pairing rules to only operate on anonymous annotations (i.e. content directly contained by an <{rtc}>).
+	<li>Apply 'ruby-position' to ''::first-line''.
+		(<a href="https://github.com/w3c/csswg-drafts/issues/2998">Issue 2998</a>)
 </ul>
 
 <h3 id="changes-20130919">