Clarify paragraph about color/style transitions in response to <http://lists.w3.org/Archives/Public/www-style/2012Mar/0258.html>

Author: fantasai

css3-background/Overview.html

@@ -2872,10 +2872,10 @@ <h3 id=corner-transitions><span class=secno>5.4. </span>Color and Style
 
   <p>If one of these borders is zero-width, then the other border takes up
    the entire transitional area. Otherwise, the center of color and style
-   transitions between adjoining borders must be proportional to the ratio of
-   the border widths such that a function of its location is continuous with
-   respect to this ratio. However it is not defined what these transitions
-   look like or how &ldquo;proportional&rdquo; maps to a point on the curve.
+   transitions between adjoining borders is a point along the curve that is a
+   continuous monotonic function of the ratio of the border widths. However
+   it is not defined what these transitions look like or what function maps
+   from this ratio to a point on the curve.
 
   <div class=figure>
    <p><img alt="Illustration of the transition region on curved corners"

css3-background/Overview.src.html

@@ -2025,10 +2025,10 @@ <h3 id="corner-transitions">Color and Style Transitions</h3>
 <p>If one of these borders is zero-width, then the other border takes
 up the entire transitional area. Otherwise,
 the center of color and style transitions between adjoining borders
-must be proportional to the ratio of the border widths such that a
-function of its location is continuous with respect to this ratio.
-However it is not defined what these transitions look like or how
-&ldquo;proportional&rdquo; maps to a point on the curve.
+is a point along the curve that is a continuous monotonic function
+of the ratio of the border widths. However it is not defined what these
+transitions look like or what function maps from this ratio to a point
+on the curve. 
 
 <div class="figure">
   <p><img alt="Illustration of the transition region on curved corners"