Global Design (incl styles)

I am coming from another CMS, helping a client improve their website, and evaluating for a potential different much larger website too. I can't understand why I have to set fonts for every page and one change requires a change to every page. I just had an issue where a global block's font was changed by a page's style. How do people manage this for big sites? Or am I trying to use Ontraport in a way it's not meant to be and it should be for smalll sales sites?

How about a design object that incorporates a header, a footer, settings for fonts, and a stylesheet and you can select it for a page?