text: 'use strict'
  
  const sizeUpBtn = document.getElementById('sizeUp')
  const sizeDownBtn = document.getElementById('sizeDown')
  let size
  
  sizeUpBtn.onclick = function () {
      size = localStorage.getItem('size')
      chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
          chrome.tabs.executeScript(
              {code: 'document.body.style.fontSize = "' + size + 'px"'})
        })
      size = parseInt(size) + 2
      localStorage.setItem('size', size)
  }
  
  sizeDownBtn.onclick = function () {
      size = localStorage.getItem('size')
      chrome.tabs.query({active: true, currentWindow: true}, function(tabs) {
          chrome.tabs.executeScript(
              {code: 'document.body.style.fontSize = "' + size + 'px"'})
        })
      size = parseInt(size) - 2
      if (size <= 10) {
        size = 10
      }
      localStorage.setItem('size', size)
  }
  