Specify various properties for windows matching CONDITION. See the `Face Specification Flags' and `Window Style' sections for details. CONDITION can be a string in which case default-style-condition-handler is used, or it can be a list of two elements in which case the first is the X class name to match and the second is the X resource name to match (both must match). CONDITION can also be an arbitrary predicate that takes a window and returns #t iff that window is to be considered a match.