[css-writing-modes] Clarifications to orthogonal block container auto sizing

Author: fantasai

css-writing-modes/Overview.bs

@@ -2062,16 +2062,17 @@ Auto-sizing Block Containers in Orthogonal Flows</h4>
     else it is calculated from the used 'column-width', 'column-count', and 'column-gap'.
 
   <p>
-    The used <i>block size</i> of the box is either the used column <i>block size</i>
+    The used <i>block size</i> of the box is either the used column length
     (if multiple columns were used)
-    or the <i>max-content block size</i> of the content.
+    or the <i>max-content block size</i> of the content
+    (if only one column was used).
 
   <p>
     If the UA does not support CSS Multi-column Layout [[!CSS3COL]],
-    the UA may instead calculate the box's <i>inline size</i> assuming an infinite <i>block size</i>,
+    the UA may instead calculate the box's <i>block size</i> assuming an infinite <i>available block size</i>,
     thus laying out its contents into a single column.
-    Note that this can, however, result in content that is clipped
-    or otherwise inaccessible.
+    (Note that this can, however, result in content that is clipped
+    or otherwise inaccessible if it overflows its containing block.)
 
   <p class="issue"><a href="https://lists.w3.org/Archives/Public/www-style/2015Apr/0212.html">Defer proposal in ML</a> not resolved yet</p>