* `phui-calendar-bg-blue`
* `phui-calendar-bg-green`
* `phui-calendar-bg-grey`
* `phui-calendar-bg-indigo`
* `phui-calendar-bg-orange`
* `phui-calendar-bg-red`
* `phui-calendar-bg-sky`
* `phui-calendar-bg-viewer-invited`
* `phui-calendar-bg-violet`
* `phui-calendar-bg-yellow`
* `phui-calendar-blue`
* `phui-calendar-green`
* `phui-calendar-grey`
* `phui-calendar-indigo`
* `phui-calendar-orange`
* `phui-calendar-red`
* `phui-calendar-sky`
* `phui-calendar-violet`
* `phui-calendar-yellow`
* `phui-calendar-event-empty`
* `phui-calendar-list-dot`
* `phui-calendar-viewer-invited`
** Added in https://we.phorge.it/rP396e8ba82c221c085d17f1574551fbff42459452, usage removed in https://we.phorge.it/rP4016107411c12d8658a2cfeefeef19b7c12fa6cb resp. https://we.phorge.it/rPb6c3d184d200e6bc43ba8f15a069c3a8620779cc from src/view/phui/calendar/PHUICalendarListView.php