I got into same problem you had - the trick is to have view/parent components not use Shadow DOM - then you can use normal css styling, or alternatively prepar

I got into same problem you had - the trick is to have view/parent components not use Shadow DOM - then you can use normal css styling, or alternatively prepare a `shared-styles` file that will contain styles shared across elements. IMO having everything inside Shadow DOM is an anti-pattern. I use my own pipeline based on gulp so I don't know much about polymer bundler, webpack support was recently added though, I haven't used it yet.