Merge pull request w3c#1709 from cookiecrook/mq5/prefers-reduced-transparency

MQ5 User Prefs: prefers-reduced-transparency

Author: frivoal

mediaqueries-5/Overview.bs

@@ -478,6 +478,36 @@ Detecting the desire for less motion on the page: the 'prefers-reduced-motion' f
 
 	</dl>
 
+<h3 id="prefers-reduced-transparency">
+Detecting the desire for reduced transparency on the page: the 'prefers-reduced-transparency' feature</h3>
+
+	<pre class='descdef mq'>
+	Name: prefers-reduced-transparency
+	Value: no-preference | reduce
+	For: @media
+	Type: discrete
+	</pre>
+
+	The 'prefers-reduced-transparency' media feature is used to detect if the user
+	has requested the system minimize the amount of transparent or translucent 
+	layer effects it uses.
+
+	<dl dfn-type=value dfn-for="@media/prefers-reduced-transparency">
+		<dt><dfn>no-preference</dfn>
+		<dd>
+			Indicates that the user has made no preference known
+			to the system. This keyword value evaluates as false
+			in the <a>boolean context</a>.
+
+		<dt><dfn>reduce</dfn>
+		<dd>
+			Indicates that user has notified the system that they
+			prefer an interface that minimizes the amount of 
+			transparent or translucent layer effects.
+
+	</dl>
+
+
 <h2 id="changes" class="no-num">
 Changes</h2>
 <h3 id="changes-2017">
@@ -493,6 +523,10 @@ The following changes were made to this specification since the
 
 	<li>
 		Add 'prefers-reduced-motion' media feature.
+
+	<li>
+		Add 'prefers-reduced-transparency' media feature.		
+
 </ul>