 
    // :host(:not([selected]), more general support requires
    // parsing which seems like overkill
    var HOST_PAREN = /(\:host)(?:\(((?:\([^)(]*\)|[^)(]*)+?)\))/g;
    var CONTENT = '::content';
    var SCOPE_JUMP = /\:\:content|\:\:shadow|\/deep\//;
    var CSS_CLASS_PREFIX = '.';
    var CSS_ATTR_PREFIX = '[' + SCOPE_NAME + '~=';
    var CSS_ATTR_SUFFIX = ']';
    var PSEUDO_PREFIX = ':';

    // exports
    Polymer.StyleTransformer = {
      element: transformElement,
      dom: tran