I am trying to make protostar template BACKEND more user friendly. I want to add a left sidebar with options such as "Fonts", "Layout", "..." etc. I also would like to be able to style the backend options, fieldsets and fields.
Please note: This question is for the Joomla administrator backend and not for the front end site.
I know html and css well but I dont know where to override the backend template manager looks like some of the theme providers do. For example: