The existing font changer on mobilefrontend uses +/- controls and a the feedback is given with a % value to the user. This is a complicated control to use and the user expectation of 100%/110% is difficult to grasp.
Create easy buckets of font sizes
1. Small - 90%
2. Regular - 100% (default)
3. Large - 120%
4. Extra Large - 140%
The buckets can be selected with a [[ https://doc.wikimedia.org/oojs-ui/master/demos/?page=widgets&theme=wikimediaui&direction=ltr&platform=desktop#DropdownWidget | dropdown widget. ]]
== Developer notes
We'll introduce the OOUI library (PHP+CSS) on this page. JS should not be needed since this is a simple form.
== Acceptance criteria
 OOUI css should not be loaded on any page other than Special:MobileOptions
 Document the change of size in CSS and JS on this page somewhere under mw.org Reading/Web so that we have data about what the impact of including OOUI is on a given page