Fullcalendar - change color of event based on value

I use the latest fullcalendar and wondered if anyone can show me how I can change the background color of an event based on its value? For example, if the value is Yes, then bg will be green, and if the value is No, then bg will be red (my Description field is the actual field that contains the values ​​Yes or No). Here is the code I have:

 $(document).ready(function() {
  var date = new Date();
  var d = date.getDate();
  var m = date.getMonth();
  var y = date.getFullYear();

  var calendar = $('#calendar').fullCalendar({
   editable: true,
   header: {
    left: 'prev,next today',
    center: 'title',
    right: 'month,agendaWeek,agendaDay'
   },

   events: "events.php",

   // Convert the allDay from string to boolean
   eventRender: function(event, element, view) {
    if (event.allDay === 'true') {
     event.allDay = true;
    } else {
     event.allDay = false;
    }
    element.find('.fc-event-title').append("<br/>Successful?: <span class='myClass'><b>" + event.description + "</b></span>");
   },
   selectable: false,
   selectHelper: true,
   select: function(start, end, allDay) {
   var title = prompt('Event Title:');
   var url = prompt('Type Event url, if exits:');
   if (title) {
   var start = $.fullCalendar.formatDate(start, "yyyy-MM-dd HH:mm:ss");
   var end = $.fullCalendar.formatDate(end, "yyyy-MM-dd HH:mm:ss");
   $.ajax({
   url: 'add_events.php',
   data: 'title='+ title+'&start='+ start +'&end='+ end +'&url='+ url ,
   type: "POST",
   success: function(json) {
   alert('Added Successfully');
   }
   });
   calendar.fullCalendar('renderEvent',
   {
   title: title,
   start: start,
   end: end,
   allDay: allDay
   },
   true // make the event "stick"
   );
   }
   calendar.fullCalendar('unselect');
   },

   editable: false,
   eventDrop: function(event, delta) {
   var start = $.fullCalendar.formatDate(event.start, "yyyy-MM-dd HH:mm:ss");
   var end = $.fullCalendar.formatDate(event.end, "yyyy-MM-dd HH:mm:ss");
   $.ajax({
   url: 'update_events.php',
   data: 'title='+ event.title+'&start='+ start +'&end='+ end +'&id='+ event.id ,
   type: "POST",
   success: function(json) {
    alert("Updated Successfully");
   }
   });
   },
   eventResize: function(event) {
   var start = $.fullCalendar.formatDate(event.start, "yyyy-MM-dd HH:mm:ss");
   var end = $.fullCalendar.formatDate(event.end, "yyyy-MM-dd HH:mm:ss");
   $.ajax({
    url: 'update_events.php',
    data: 'title='+ event.title+'&start='+ start +'&end='+ end +'&id='+ event.id ,
    type: "POST",
    success: function(json) {
     alert("Updated Successfully");
    }
   });

}

  });

 });

Thank.