Unless I'm mistaken it does not look as if this control has any CSS support like the other daypilot controls? Since there is no asp.net SkinID available either there is no way to theme this control.
In addition to lack of CSS support, it looks as if many styling attirbutes are not possible even in markup (such as menu title foreground color?). It looks as if it is always black, so if you use a dark menu title background color, you cannot see the title.
Are there any plans to add CSS support and / or improve styling attributes?