; (function () {
  'use strict'
  const accordionEl = document.getElementsByClassName('accordion-header')

  function openAccordion (parent, panel) {
    parent.classList.add('is-active')
    panel.style.maxHeight = panel.scrollHeight + 'px'
  }

  function closeAccordion (parent, panel) {
    parent.classList.remove('is-active')
    panel.style.maxHeight = null
  }

  if (accordionEl.length > 0) {
    for (let i = 0; i < accordionEl.length; i++) {
      const el = accordionEl[i]
      const parent = el.parentNode
      const panel = el.nextElementSibling
      parent.classList.contains('is-active') && openAccordion(parent, panel)
      el.addEventListener('click', function () {
        parent.classList.contains('is-active') ? closeAccordion(parent, panel) : openAccordion(parent, panel)
      })
    }
  }
}())