Have Style attributes for text to ensure consistency across multiple screens
When you have multiple screens for a project it is hard to remember what all the font size and font attributes are from one screen to the next. Introduce styles like h1, h2 and body so that all of the screens in a project have consistent use of text size and headings etc.
Filip Zajac commented
I like the way of stylesheets. It's a perfect starting point for any UI designer, but it's quite too simple. I would appreciate more advanced text/paragraph styles options -* really missing line height and all font weights here. I often build Hi-Fidelity prototypes which could be done quickly only with Hi-Fi styles. Some margin/padding settings would be helpful too, but not the way of container box.