Hi Mike and Andrew,
I'm sorry to hear about your experience with the way your styles have been applied in the backend.
We appreciate you sharing this feedback with us, and would like to review this behavior, so we can give you the best advice in this case, or verify if's not caused by some internal issue.
To help us establish the above, would it be possible to present us with the masterpage files you've been using, so we can replicate the behavior locally and study it further?
Thnak you in advance for the kind cooperation!
the Telerik team