How to change template of DateTimePicker

[Torchok19081986]

Hallo i want to use currently mahapps metro datetimepicker for own project, but i have to customize template of datetimepicker. How can i set for example calendaritemstyle or foreground of days instead of black color? Is there possiblity to change headerstyle as well by creating custom ressourcedictionary or not ? Many thanks for advice and answers.