Widget are referencing css class which does not exists in src

[valentinMachado]

Widget class add css class to its domElement but these class does not exists in src but in examples/css/widgets.css.

Do you consider that the user has to know that he has to define these classes on its own ?
Why not setting css in the domElement directly ? (making clearer that Widget is handling some css and working on its own)
create css class in javascript or webpack css
Why not remove all css behavior if you consider that this is the user which have to deals with it ? (making this class quite empty)

[jailln]

I agree with your last proposition that we should leave everything regarding style to the user, see #2005 (the css part). You can modify it accordingly