Change Font Sizes sitewide (option for yes or no)

To allow for even more visual and branding consistency, give the user/editor an option to change the size of each title, header and body text universally throughout the website. Many times it's hard to keep track and keep this consistent when building out a large site with a lot of content and pages. This option could be a yes/no switch on the left-hand dashboard that if activated, could not only allow for changing font types but also font sizes according to title-header-body.