text: class Style {
      constructor(id) {
          this._id = id;
          this._addStyleElement()
      }
      get Id() { return this._id; }
      add(css) {
          const style = document.getElementById(this._id);
          if (!style.innerText.includes(css)) {
              style.appendChild(document.createTextNode(css));
          }
      }
      _addStyleElement() {
          const head = document.getElementsByTagName('head').item(0);
          const style = document.createElement('style');
          style.setAttribute('id', this._id)
          style.media = 'screen';
          style.type = 'text/css';
          head.appendChild(style);
      }
  }
  