Minor color update

docs/v2/DEVLOG.md

@@ -615,3 +615,4 @@
 ## 20161207
 
 - Documented `radio` and `checkbox` in the `input_control` doc page.
+- Tweaked all references of `$back-color` to now use `#fafafa` instead of the previous `#f5f5f5`. This will make contrast better and allow for better visibility of certain pieces of text.

docs/v2/playground.html

@@ -197,9 +197,9 @@
             <button disabled>Disabled button</button><br>
             <p>Button groups can also be created, utilising the <code>.button-group</code> class. Simply add a set of buttons in it and you're good to go. Check it out below:</p>
             <div class="button-group">
-              <input type="button" value="Input button">
-              <input type="submit" value="Submit button">
-              <input type="reset" value="Reset button">
+              <input type="button" value="Input button" class="secondary">
+              <input type="submit" value="Submit button" class="primary">
+              <input type="reset" value="Reset button" class="inverse">
               <button>Normal button</button>
               <a href="#" class="button">Link button</a>
             </div>