[css-writing-modes] Add headers, shift around content.

Author: fantasai

css-writing-modes/Overview.bs

@@ -908,6 +908,23 @@ Obsolete SVG1.1 'writing-mode' Values</h4>
   <p>These values are <em>obsolete</em> in any context except SVG1 documents
     and are therefore <em>optional</em> for non-SVG UAs.
 
+  <div class="note">
+    In SVG1.1, these values set the <dfn>inline progression direction</dfn>,
+    in other words, the direction the current text position
+    advances each time a glyph is added. This is a geometric process that
+    happens <em>after</em> bidi reordering, and thus has no effect on the
+    interpretation of the 'direction' property (which is independent of
+    'writing-mode'). (See <a href="http://www.w3.org/TR/SVG/text.html#RelationshipWithBiDirectionality">Relationship
+    with bidirectionality</a>. [[!SVG11]])
+
+    There are varying interpretations
+    on whether this process causes "writing-mode: rl" to merely shift the
+    text string or reverse the order of all glyphs in the text.
+  </div>
+
+<h5 id="svg-writing-mode-css" class="no-toc">
+Supporting SVG1.1 'writing-mode' values in CSS syntax</h5>
+
   <p>UAs that wish to support these values in the context of CSS
     must treat them as follows:
 
@@ -930,21 +947,10 @@ Obsolete SVG1.1 'writing-mode' Values</h4>
     specification. The additional ''tb-lr'' value of that revision is
     replaced by ''vertical-lr''.
 
-  <div class="note">
-    In SVG1.1, these values set the <dfn>inline progression direction</dfn>,
-    in other words, the direction the current text position
-    advances each time a glyph is added. This is a geometric process that
-    happens <em>after</em> bidi reordering, and thus has no effect on the
-    interpretation of the 'direction' property (which is independent of
-    'writing-mode'). (See <a href="http://www.w3.org/TR/SVG/text.html#RelationshipWithBiDirectionality">Relationship
-    with bidirectionality</a>. [[!SVG11]])
-
-    There are varying interpretations
-    on whether this process causes "writing-mode: rl" to merely shift the
-    text string or reverse the order of all glyphs in the text.
-  </div>
+<h5 id="svg-writing-mode-markup" class="no-toc">
+Supporting SVG1.1 'writing-mode' values in presentational attributes</h5>
 
-  <p>In order to support legacy content,
+  <p>In order to support legacy content with presentational attributes,
   and to allow authors to create documents that support older clients,
   SVG UAs must add the following style sheet rules to their default UA stylesheet:
 
@@ -958,7 +964,7 @@ Obsolete SVG1.1 'writing-mode' Values</h4>
   </pre>
 
   <div class="note">
-    Authors who wish to create forwards and backwards-compatible content
+    Authors who wish to create forwards and backwards-compatible SVG content
     in CSS syntax can use the CSS forwards-compatible parsing rules to do so,
     e.g.