Polymer does this but a fairly substantial performance cost You essentially override every method of the DOM to filter out elements that are inside in the fake shadow DOM I we're sort of waiting for browsers implement that stuff are, in the meantime we actually are encouraging people to style things because we think that some widgets should be better style to reflect environment there on, for example which is for Firefox OS should look sort of like the widgets are shipped inside of Gaia and we just iOS could perhaps have another skin that ship alongside, so for now we are not correcting people for stamping on styles but we're trying to allow it in a way that makes the quality better. 