Froala custom feature - button to change CSS on element where blinking cursor is at

I am using Froala rich text editor. Would like a custom button on the toolbar, whereby when you click it, it will apply custom CSS to the element where the blinking cursor is located. Very similar to when you put your cursor on a line, click on H1 button, then that element changes to H1 style. I Just want it to have a custom button that produces a hanging indent, italicized, with a light colored grey background. A JSfiddle delivery would be acceptable.