[css-ruby-1] Switch to fullwidth parens, add rule for the basic rt-only case. #762

Author: fantasai

css-ruby-1/Overview.bs

@@ -1572,24 +1572,39 @@ Appendix A: Default Style Sheet</h2>
 
 	Unfortunately, because Selectors cannot match against text nodes,
 	it's not possible with CSS to express rules that will automatically and correctly
-	add parentheses to unparenthesized ruby annotations in HTML.
-	(This is because HTML ruby allows implying the [=ruby base=] from raw text, without a corresponding element.)
-	However, these rules will handle cases where either <code>&lt;rb&gt;</code>
-	or <code>&lt;rtc&gt;</code> is used rigorously.
+	add parentheses to unparenthesized ruby annotations
+	for all possible ruby markup patterns in HTML.
+	(This is because HTML ruby allows implying the [=ruby base=] from raw text
+	without a corresponding element.)
+
+	However, these rules will add parentheses around each annotation sequence
+	in cases where either <code>&lt;rb&gt;</code>
+	or <code>&lt;rtc&gt;</code> is used rigorously:
 
 	<pre highlight=css>
 		/* Parens around &lt;rtc> */
-		rtc::before { content: "("; }
-		rtc::after  { content: ")"; }
+		rtc::before { content: "（"; }
+		rtc::after  { content: "）"; }
 
 		/* Parens before first &lt;rt> not inside &lt;rtc> */
 		rb  + rt::before,
-		rtc + rt::before { content: "("; }
+		rtc + rt::before { content: "（"; }
 
 		/* Parens after &lt;rt> not inside &lt;rtc> */
 		rb ~ rt:last-child::after,
-		rt + rb::before  { content: ")"; }
-		rt + rtc::before { content: ")("; }</pre>
+		rt + rb::before  { content: "）"; }
+		rt + rtc::before { content: "）（"; }</pre>
+
+	Alternatively, if it is known that a purely alternating style of markup is used
+	(<code>&lt;ruby>A<rt>a</rt>B<rt>b</rt>C<rt>c</rt>&lt;ruby></code>)
+	where there are no adjacent ruby annotations,
+	the following rules will add parentheses around each annotation:
+
+	<pre highlight=css>
+		/* Parens around each &lt;rt> */
+		rt::before { content: "（"; }
+		rt::after  { content: "）"; }
+	</pre>
 
 <h2 id="glossary">
 Glossary</h2>