re-arrange and fix p markup

move the scoping of exceptions section into the exceptions section (preceded it, and that was weird)

also fixes a paragraph with a missing start tag

understanding/21/reflow.html

@@ -82,8 +82,18 @@ <h4>Horizontally scrolling section within a vertically scrolling page</h4>
         </figure>
 
 
-        <h4>Understanding the scope of exceptions</h4>
-        <p>Where a section or sections of content within a web page require bi-directional scrolling, this does not grant an exception to other sections of content.</p>
+
+      </section>
+      <section>
+        <h3>Exceptions and content considerations for Reflow</h3>
+        <p>
+          For many 'traditional' web pages where its primary purpose is for a user to read distinct short or long-form <a href="https://www.w3.org/TR/WCAG/#dfn-section">sections of content</a>, the web page is generally expected to scroll vertically (when written in languages such as English). For users with low vision who may need to zoom the web page to read its content, it is generally expected that as the viewport size decreases due to the increase in zoom level, that the content of the page would reflow to fit within the confines of the viewport.</p>
+        <p>
+          Ideally, all sections of content would be able to reflow, allowing the content to be more easily read by users. However, not all content can reflow without degradation of the information or functionality the content represents - for instance, content which requires two-dimensional layout.
+        </p>
+
+         <h4>Understanding the scope of exceptions</h4>
+        <p>Where an exception for bi-directional scrolling would be applicable to a section or sections of content within a web page, such an exception does not extend to other sections of content which do not necessitate bi-directional scroling for understanding or functionality.</p>
         <p>For example, while a data table would be given an exception to Reflow, presenting the table in a container which itself can scroll would help ensure other content which does not meet an exception could reflow as the viewport adjusts.</p> 
         <figure>
           <img src="img/table-exception.jpg" alt="a table within a containing element that provides bi-directional scrollbars to view the content of the table. The content above and below the table reflows to fit within the available width of the viewport.">
@@ -118,14 +128,6 @@ <h4>Understanding the scope of exceptions</h4>
             <p>By providing the video player a <code>max-width: 100%</code> CSS property, the video now fits within the container element and thus no horizontal scroll bar is present on the page.</p>
           </figcaption>
         </figure>
-      </section>
-      <section>
-        <h3>Exceptions and content considerations for Reflow</h3>
-        <p>
-          For many 'traditional' web pages where its primary purpose is for a user to read distinct short or long-form <a href="https://www.w3.org/TR/WCAG/#dfn-section">sections of content</a>, the web page is generally expected to scroll vertically (when written in languages such as English). For users with low vision who may need to zoom the web page to read its content, it is generally expected that as the viewport size decreases due to the increase in zoom level, that the content of the page would reflow to fit within the confines of the viewport.</p>
-        <p>
-          Ideally, all sections of content would be able to reflow, allowing the content to be more easily read by users. However, not all content can reflow without degradation of the information or functionality the content represents - for instance, content which requires two-dimensional layout.
-        </p>
 
         <h4>Graphics and video</h4>
         <p>For example, graphics and video are by their nature two-dimensional. Cutting up a graphic (photograph, drawing, graph, etc.) and stacking the blocks would make the graphic difficult to understand, if not rendering it unintelligible. However, it is possible to have these elements stay within the bounds of the viewport even as other content zooms to 400% (see advisory techniques).</p>
@@ -160,7 +162,7 @@ <h4>Interfaces with persistent toolbars</h4>
         </figure>
 
         <h4>Layout needed for usage and meaning</h4>
-        Additionally, many of these sorts of interfaces allow users to create content set to defined dimensions. For instance, presentations or documents based on physical printing or display sizes. These interfaces often allow for other related content to be created as directly related content to the primary author created content - e.g., presentation notes, editing comments/suggestions for a text document, dynamic messaging presented along with a message interface, etc. Each of these related sections of content often need to be presented in parallel to each other, and their understandability can diminish if their overall location were to change. For example, comments pertaining to a paragraph of text on one page of a document can be difficult to understand if they're not presented directly next to each other. Reflowing the comment inline with the document could cause the content of the document to be misrepresented or misconstrued as all being content written by the document's author, rather than separate authors (original author and editor).</p>
+        <p>Additionally, many of these sorts of interfaces allow users to create content set to defined dimensions. For instance, presentations or documents based on physical printing or display sizes. These interfaces often allow for other related content to be created as directly related content to the primary author created content - e.g., presentation notes, editing comments/suggestions for a text document, dynamic messaging presented along with a message interface, etc. Each of these related sections of content often need to be presented in parallel to each other, and their understandability can diminish if their overall location were to change. For example, comments pertaining to a paragraph of text on one page of a document can be difficult to understand if they're not presented directly next to each other. Reflowing the comment inline with the document could cause the content of the document to be misrepresented or misconstrued as all being content written by the document's author, rather than separate authors (original author and editor).</p>
 
         <figure>
           <img src="img/rich-document-with-comment.png" alt="online rich text document - on the left: the text document is displayed at dimensions representing the physical width and height of the page.  On the right, a comment referring to highlighted text in the text document.">