detach() {
    if (!this.sheet) return
    const {parentNode} = this.element
    if (parentNode) parentNode.removeChild(this.element)
    // In the most browsers, rules inserted using insertRule() API will be lost when style element is removed.
    // Though IE will keep them and we need a consistent behavior.
    if (this.sheet.options.link) {
      this.cssRules = []
      this.element.textContent = '\n'
    }
  }
Remove style element from render tree.