README: add :host() 1-level nested parentheses limitation. Fixes https://github.com/Polymer/docs/issues/197
README: add :host() 1-level nested parentheses limitation. Fixes https://github.com/Polymer/docs/issues/197
modulexcite/ShadowDOM,googlearchive/ShadowDOM,Polymer/ShadowDOM,modulexcite/ShadowDOM