[css-sizing-3] Improve definition of min-content size. w3c#6418

Author: fantasai

css-sizing-3/Overview.bs

@@ -238,24 +238,23 @@ Auto Box Sizes</h3>
 
 		<dt><dfn lt="min-content | min-content size">min-content size</dfn>
 		<dd>
-			The smallest <a>size</a> a box could take
+			Nominally, the smallest <a>size</a> a box could take
 			that doesn't lead to overflow
 			that could be avoided by choosing a larger <a>size</a>.
-			(See [[#intrinsic]].)
+			Formally, the size of the box when sized under a [=min-content constraint=],
+			see [[#intrinsic]].
 
 			: <dfn>min-content inline size</dfn>
-			:: The narrowest <a>inline size</a> a box could take
-				that doesn't lead to inline-dimension overflow
-				that could be avoided by choosing a larger <a>inline size</a>.
-				Roughly, the <a>inline size</a> that would fit around its contents
+			:: The [=min-content size=] in the [=inline axis=].
+				Typically, the <a>inline size</a> that would fit around its contents
 				if <em>all</em> soft wrap opportunities within the box were taken.
 
 				Note: This is called the “preferred minimum width” in <a href="https://www.w3.org/TR/CSS2/visudet.html#float-width">CSS2.1§10.3.5</a>
 				and the “minimum content width” in <a href="https://www.w3.org/TR/CSS2/tables.html#auto-table-layout">CSS2.1§17.5.2.2</a>.
 
 			: <dfn>min-content block size</dfn>
-			:: In general,
-				and definitely for [=block containers=], tables, and [=inline boxes=],
+			:: The [=min-content size=] in the [=block axis=].
+				For [=block containers=], tables, and [=inline boxes=],
 				this is equivalent to the <a>max-content block size</a>.
 
 		<dt><dfn>fit-content size</dfn>