<div class="modal-header">
  <button type="button" class="close" ng-click="close()">&times;</button>
  <h4>Edit Registration</h4>
</div>
<div class="modal-body">

  <div ng-repeat="page in conference.registrationPages">
    <div ng-repeat="block in page.blocks" block="block" answer="findAnswer(block.id)" crs-block></div>
  </div>
</div>
<div class="modal-footer">
  <h4 ng-show="saving"><i class="fa fa-circle-o-notch fa-spin"></i> Saving...</h4>
  <div ng-show="!saving">
    <button ng-click="submit(true)" class="btn btn-default" ng-show="!registration.completed">Save &amp; Set as Completed</button>
    <button ng-click="submit()" class="btn btn-primary">Save</button>
  </div>
</div>

<div class="modal-header">
  <button type="button" class="close" ng-click="close()">&times;</button>
  <h4>Edit Registration</h4>
</div>
<div class="modal-body">

  <div ng-repeat="page in conference.registrationPages">
    <div ng-repeat="block in page.blocks" block="block" answer="findAnswer(block.id)" crs-block></div>
  </div>
</div>
<div class="modal-footer">
  <h4 ng-show="saving"><i class="fa fa-circle-o-notch fa-spin"></i> Saving...</h4>
  <div ng-show="!saving">
    <button ng-click="submit(true)" class="btn btn-primary" ng-show="!registration.completed">Save &amp; Set as Completed</button>
    <button ng-click="submit()" class="btn btn-primary">Save</button>
  </div>
</div>
Change button style to btn-primary
Change button style to btn-primary
