Responsive design in Storyline 360

Hi all, i understand Rise is your answer to truly responsive content, but what irks me the most with it is that i have clients with certain branding guidelines and font types for their content which seems i wont be able to achieve when building in Rise? How on earth did the developers of this product not understand that we might need this flexibility? I love how simple it is and easy to use but seriously you need to be able to customize much more of the content.