[css-counter-styles-3] Make 'width' respect negative-capable.

Author: tabatkins

css-counter-styles-3/Overview.html

@@ -1240,11 +1240,12 @@ <h3 id=counter-style-width><span class=secno>3.6. </span> Zero-Padding and
     prefixes/suffixes/negatives), prepend copies of the specified <a
     href="#ltsymbol"><var>&lt;symbol></var></a> to the representation until
     the number of symbols reaches the specified width.
-    <p> If the counter value is negative, reduce the width by one or two when
-     determining how many copies to prepend, depending on whether the ‘<a
-     href="#descdef-negative"><code class=property>negative</code></a>’
-     descriptor's value is one or two <a
-     href="#ltsymbol"><var>&lt;symbol></var></a>s.
+    <p> If the counter value is negative and the counter style is <a
+     href="#negative-capable"><i>negative-capable</i></a>, reduce the width
+     by one or two when determining how many copies to prepend, depending on
+     whether the ‘<a href="#descdef-negative"><code
+     class=property>negative</code></a>’ descriptor's value is one or two
+     <a href="#ltsymbol"><var>&lt;symbol></var></a>s.
   </dl>
 
   <div class=example> The most common example of "fixed-width" numbering is

css-counter-styles-3/Overview.src.html

@@ -866,7 +866,8 @@ <h3 id='counter-style-width'>
 			until the number of symbols reaches the specified width.
 
 			<p>
-				If the counter value is negative,
+				If the counter value is negative
+				and the counter style is <i>negative-capable</i>,
 				reduce the width by one or two when determining how many copies to prepend,
 				depending on whether the 'negative' descriptor's value is one or two <var>&lt;symbol></var>s.
 	</dl>