added text for sprites

Author: khan4019

css.html

@@ -473,8 +473,10 @@ <h2>17. vertical Center</h2>
 </div>
 <div id="something">
   <h2>18. sprite</h2>
-  <p><strong></strong></p>
-  <p><strong></strong></p>
+  <p><strong>Question:</strong> Why would you use sprites?</p>
+  <p><strong>Answer:</strong> When you have multiple images/icons, browser makes seperate call to the server for each one of them. sprite is a technique to combine all of them (usually similar one in terms of type of image. For example, you will put jpg in one sprite) in one image. you can later optimize the image. To display the icon you set height, width and background position.</p>
+  <p>popular libraries like bootstrap use this technques. If you repeat the image. want to scale you have to be careful with sprite.</p>
+  <p>ref: <a href="http://coding.smashingmagazine.com/2009/04/27/the-mystery-of-css-sprites-techniques-tools-and-tutorials/">css sprites</a>, <a href="http://css.spritegen.com/">generate sprites</a></p>
 </div>
 <div id="mtuli_lang">
   <h2>19. pre processor</h2>