changed button color

Author: TBosak

public/index.html

@@ -127,7 +127,7 @@
       <button data-field="longSelector" class="contrast small">Longitude</button>
       <button data-field="sourceUrlSelector" class="contrast small">Source URL</button>
       <button data-field="sourceTitleSelector" class="contrast small">Source Title</button>
-      <button id="closePlaygroundBtn" class="contrast small">Close</button>
+      <button id="closePlaygroundBtn" class="small">Close</button>
     </div>
   </div>
   <article id="form">