constructor(host) {
    (this.host = host).addController(this);
    // Perhaps use constructable stylesheets instead once Safari supports replace(Sync) methods
    this.__styleTag = document.createElement('style');
    this.scopedClass = `${this.host.localName}-${Math.floor(Math.random() * 10000)}`;
  }
@param {ReactiveControllerHost & import('lit').LitElement} host