if (document.body) {
  function addLayoutClass(e) {
    if (e.matches) {
      document.body.classList.remove('is-desktop');
      document.body.classList.add('is-phone');
    } else {
      document.body.classList.add('is-desktop');
      document.body.classList.remove('is-phone');
    }
  }

  const layoutMediaQuery = window.matchMedia("(max-width: 767px)")
  addLayoutClass(layoutMediaQuery)
  layoutMediaQuery.addEventListener('change', addLayoutClass)
}