Styles will be removed from dev guide. In general the components has too many classes attributes and we think it isn't usefull to duplicate them with corresponding style-ones. Anyway it isn't good style to use it instead of class attributes isn't so?
But what if have a common class for all panels and would like to have just one panel body to have a specific height and a scrollbar. Is it a good style to create just one class in style file for height 500px or just put it in the style attribute?