[fix] Force validate button to be show (force color to white)

www/templates/login/modal_login.html

@@ -8,7 +8,7 @@
     <div class="buttons buttons-right">
       <div class="secondary-buttons">
         <button class="button button-icon button-clear icon ion-android-done visible-xs"
-                ng-class="{'button-positive': !isAuth}"
+                ng-class="{'button-positive': !isAuth}" style="color: #fff;"
                 ng-click="doLogin()">
         </button>
       </div>