Thank you for this question.
Currently only our controls can be styled using our theming mechanism. We built our controls from the ground up to support styling and will be not easy to provide the same functionality for MS controls. Nevertheless, we constantly try to extend our portfolio and we will add more controls in future. We also try to keep our API similar with the MS API, so as to be easy replacing default controls with ours.
I hope this helps. Should you have any further questions, do not hesitate to ask.
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