fixed typo

Author: howcom

css3-gcpm/Overview.src.html

@@ -2539,7 +2539,7 @@ <h2>Image resolution</h2>
 </div>
 
 <div class="example">
-<p>These two rule sspecifies that the UA should use the image resolution found in the image itself. If the image has no resolution, the resolution is set to 300dpi.
+<p>These rules both specify that the UA should use the image resolution found in the image itself. If the image has no resolution, the resolution is set to 300dpi.
 <pre>
 img { image-resolution: from-image 300dpi }
 img { image-resolution: 300dpi from-image }