added question about screen keyword

Author: khan4019

css.html

@@ -262,6 +262,8 @@ <h2>11. only</h2>
 &lt;style&gt;<br/>  @media only screen and (max-width: 1024px) {<br/>    margin: 0;<br/>  }<br/>&lt;/style&gt;<br/>
   </code></pre>
   <p><strong>Answer:</strong> Stops older browsers from parsing the remainder of the selector</p>
+  <p><strong>Question:</strong> Does the screen keyword apply to the device's physical screen or the browser's viewport?</p>
+  <p><strong>Answer:</strong> Browser's Viewport</p>
 </div>
 <div id="svg_canvas">
   <h2>12. overflow</h2>