This is a sample DayPilot Bubble CSS theme (bubble_default). This theme is embedded in the library.

.bubble_default_main {
  cursor: default;
}

.bubble_default_main_inner {
  border-radius: 5px;
  font-size: 12px;
  padding: 4px;
  color: #666;
  background: #eeeeee; 
  background: -webkit-gradient(linear, left top, left bottom, from(#ffffff), to(#eeeeee));
  background: -webkit-linear-gradient(top, #ffffff 0%, #eeeeee);
  background: -moz-linear-gradient(top, #ffffff 0%, #eeeeee);
  background: -ms-linear-gradient(top, #ffffff 0%, #eeeeee);
  background: -o-linear-gradient(top, #ffffff 0%, #eeeeee);
  background: linear-gradient(top, #ffffff 0%, #eeeeee);
  filter: progid:DXImageTransform.Microsoft.Gradient(startColorStr="#ffffff", endColorStr="#eeeeee");
  border: 1px solid #ccc;
  -moz-border-radius: 5px;-webkit-border-radius: 5px;
  border-radius: 5px;
  -moz-box-shadow:0px 2px 3px rgba(000,000,000,0.3),inset 0px 0px 2px rgba(255,255,255,0.8);
  -webkit-box-shadow:0px 2px 3px rgba(000,000,000,0.3),inset 0px 0px 2px rgba(255,255,255,0.8);
  box-shadow:0px 2px 3px rgba(000,000,000,0.3),inset 0px 0px 2px rgba(255,255,255,0.8);');
}