Feature Request: Content Area Class Creation

Similar to reusing Universal Content, I would love to see a function in the email editor to give specific css styling to class names and have a section to add a said class name like tagging a content block. 

It would be easier to making edits to multiple sections all at once. Currently to achieve this, you’d have to create a universal item and duplicate it a few times. Then you’d have to edit the content area “Universally” but you won’t be able to see how maybe multiple sections interact with each other with those changes you make unless you publish the changes.