[css-ruby] Various fixes to sizing, white space:

1. Remove UA-dependent font-size nonsense.
2. Add lang-specific rule for bopomofo ruby (selector needs refinement later w/ script subtags, checks against other Chinese locales, etc.).
3. Fix white-space handling errors raised by bzbarsky, sbowen, xidorn.
4. Shift bopomofo note from inter-character definition to bopomofo definition, since it's a script issue not a ruby issue.

Author: fantasai

css-ruby/Overview.bs

@@ -318,11 +318,6 @@ Anonymous Ruby Box Generation</h3>
 			This computation occurs after any intermediary anonymous-box fixup
 			(such as that required by internal table elements).
 
-		<li id="anony-gen-trim-space"><strong>Trim leading/trailing white space:</strong>
-			Any white space within a ruby structure is discarded
-			at the beginning and end of
-			a <i>ruby container</i>, <i>ruby annotation container</i>, or <i>ruby base container</i>.
-
 		<li id="anon-gen-bare-inlines"><strong>Wrap misparented inline-level content:</strong>
 			Any consecutive sequence of text and inline-level boxes
 			directly parented by a <i>ruby container</i> or <i>ruby base container</i>
@@ -333,10 +328,17 @@ Anonymous Ruby Box Generation</h3>
 
 			However, if an anonymous box so constructed contains only <i>white space</i>,
 			it is considered <dfn>intra-ruby white space</dfn>
-			and is either discarded as <i>inter-level white space</i>
-			or preserved as <i>intra-level white space</i>
+			and is either discarded
+			or preserved
 			as described below.
 
+		<li id="anony-gen-trim-space"><strong>Trim leading/trailing white space:</strong>
+			Any <i>intra-ruby white space</i>
+			that is not the sole child of its parent
+			and occurs at the beginning or end of
+			a <i>ruby container</i>, <i>ruby annotation container</i>, or <i>ruby base container</i>
+			is removed, as if it had ''display: none''
+
 		<li id="anon-gen-discard-space"><strong>Remove inter-level white space:</strong>
 			Any <i>intra-ruby white space</i>
 			whose immediately adjacent siblings match one of the patterns below
@@ -391,7 +393,7 @@ Anonymous Ruby Box Generation</h3>
 				<tr><td><i>ruby base</i> or <i>ruby base container</i>
 				    <td><i>ruby base container</i>
 				<tr><td><i>ruby base container</i>
-				    <td><i>ruby base container</i>
+				    <td><i>ruby base</i> or <i>ruby base container</i>
 			</table>
 			The <dfn>intra-level white space</dfn> boxes defined above are
 			treated specially for pairing and layout. See below.
@@ -516,7 +518,7 @@ Unit Pairing and Spanning Annotations</h4>
 <h4 id="nested-pairing">
 Complex Spanning with Nested Ruby</h4>
 
-	<p><dfn lt="nested ruby"></dfn>When <i>ruby containers</i> are nested,
+	<p>When <i>ruby containers</i> are <dfn lt="nested ruby">nested</dfn>,
 	pairing begins with the deepest <i>ruby container</i>,
 	then expands out.
 	From the pairing perspective of the outer <i>ruby container</i>,
@@ -898,14 +900,6 @@ Line Spacing</h3>
 	Note, it is currently in the process of being rewritten;
 	the current drafts should not be relied upon.
 
-<h3 id="ruby-size">Ruby Annotation Font Size</h3>
-	<p>The <i>ruby annotations</i> are usually the half size of the <i>ruby base</i> as described in [[!JLREQ]].
-		However, UA may increase the font size when the it is too small to read,
-		or decrease if the text is too large to avoid ruby annotation being too large.
-		Also, the 'ruby-position: inter-character' usually require different font size such as 25% or 33%.
-	<p>This level of the specification does not define any additional mechanism to automatically compute
-		the <i>ruby annotation</i> font size according to properties of <i>ruby container</i> or <i>ruby base</i>.
-
 <h2 id="ruby-props">
 Ruby Formatting Properties</h2>
 
@@ -1004,14 +998,6 @@ Ruby Positioning: the 'ruby-position' property</h3>
 					<p class="caption">“Bopomofo” ruby in traditional Chinese
 					(ruby text shown in blue for clarity) in horizontal layout
 				</div>
-			<p class="note">
-				Note that the user agent is responsible for ensuring the correct relative alignment and positioning of the glyphs,
-				including those corresponding to the tone marks, when displaying.
-				Tone marks are spacing characters that occur (in memory) at the end of the ruby text for each base character.
-				They are usually displayed in a separate column to the right of the bopomofo characters,
-				and the height of the tone mark depends on the number of characters in the syllable.
-				One tone mark, however, is placed above the bopomofo, not to the right of it.
-			<!-- See Taiwanese requirements doc for EPUB at http://epub-revision.googlecode.com/files/EGLS_TW_eng.ppt -->
 		</dd>
 	</dl>
 
@@ -1505,18 +1491,17 @@ Appendix A: Default Style Sheet</h2>
 <!--	-->rbc  { display: ruby-base-container; }
 <!--	-->rtc  { display: ruby-text-container; }
 <!--	-->rtc, rt { white-space: nowrap; font-size: 50%; line-height: 1; }
+<!--	-->rtc:lang(zh-TW), rt:lang(zh-TW) { font-size: 30%; } /* bopomofo */
 <!--	-->rtc > rt { font-size: inherit; }
+<!--	-->rtc:lang(zh), rt:lang(zh) { ruby-align: center; }
 <!--	-->ruby, rb, rt, rbc, rtc { unicode-bidi: isolate; }</pre>
 
 	<p>Additional rules for UAs supporting the relevant features of [[CSS3-TEXT-DECOR]] and [[CSS3-FONTS]]:
 	<pre>rtc, rt { font-variant-east-asian: ruby; text-emphasis: none; }</pre>
 
-	<p class="note">Authors should not use the above rules;
+	<p class="note">Authors should not use the above rules:
 	a UA that supports ruby layout should provide these by default.
 
-	<p class="note">For the use of the 'font-size' property,
-		please refer to <a href="#ruby-size">Ruby Annotation Font Size</a>.
-
 <h3 id="default-inline" class="no-num">
 <span class="secno">A.2</span> Inlining Ruby Annotations</h3>
 
@@ -1556,7 +1541,16 @@ Glossary</h2>
 <dl>
   <dt id="g-bopomofo" lang="zh">Bopomofo
     <dd>37 characters and 4 tone markings used as phonetics in Chinese,
-      especially standard Mandarin.</dd>
+      especially standard Mandarin.
+      <p class="note">
+          Note that the user agent is responsible for ensuring the correct relative alignment and positioning of the glyphs,
+          including bopomofo tone marks, when displaying text,
+          whether it occurs in ruby annotations or as normal inline text.
+          Bopomofo Tone marks are spacing characters that occur (in memory) at the end of the ruby text for each base character.
+          They are usually displayed in a separate column to the right of or above the bopomofo characters,
+          and the position of the tone mark depends on the number of characters in the syllable.
+          One tone mark, however, is placed before the bopomofo, not over it.
+      <!-- See Taiwanese requirements doc for EPUB at http://epub-revision.googlecode.com/files/EGLS_TW_eng.ppt -->
   <dt id="g-hanja" lang="ko">Hanja
     <dd>Subset of the Korean writing system that utilizes ideographic
       characters borrowed or adapted from the Chinese writing system. Also see