yarn add postcss-px2rem

// css相關(guān)配置
  css: {
    // 啟用 CSS modules
    modules: false,
    // 是否使用css分離插件
    extract: true,
    // 開啟 CSS source maps?
    sourceMap: false,
    // css預(yù)設(shè)器配置項(xiàng)
    loaderOptions: {
      css: {},
      postcss: {
        plugins: [
          //remUnit這個(gè)配置項(xiàng)的數(shù)值是多少呢？？？ 通常我們是根據(jù)設(shè)計(jì)圖來(lái)定這個(gè)值，原因很簡(jiǎn)單，便于開發(fā)。
          //假如設(shè)計(jì)圖給的寬度是750，我們通常就會(huì)把remUnit設(shè)置為75，這樣我們寫樣式時(shí)，可以直接按照設(shè)計(jì)圖標(biāo)注的寬高來(lái)1:1還原開發(fā)。
          require('postcss-px2rem')({
            remUnit: 75
          })
        ]
      }
    },
  }

<meta name="viewport"
    content="width=device-width, viewport-fit=cover, initial-scale=1, maximum-scale=1, minimum-scale=1, user-scalable=no">

(function flexible (window, document) {
  var docEl = document.documentElement
  var dpr = window.devicePixelRatio || 1
  var isMobileDevice = /(iPhone|iPad|iPod|iOS|Android)/i.test(navigator.userAgent);
  dpr = isMobileDevice ? dpr : 1;
  // adjust body font size
  function setBodyFontSize () {
    if (document.body) {
      document.body.style.fontSize = (12 * dpr) + 'px'
    }
    else {
      document.addEventListener('DOMContentLoaded', setBodyFontSize)
    }
  }
  setBodyFontSize();

  // set 1rem = viewWidth / 10
  function setRemUnit () {
    let width = docEl.clientWidth
    // 下面5行為自己加的代碼，pc端頁(yè)面不轉(zhuǎn)rem
    let remUnitConfig = 75
    let viewWidthMax = remUnitConfig * 10
    if (width / dpr > viewWidthMax) {
      width = viewWidthMax * dpr
    }

    var rem = width / 10
    docEl.style.fontSize = rem + 'px'
  }

  setRemUnit()

  // reset rem unit on page resize
  window.addEventListener('resize', setRemUnit)
  window.addEventListener('pageshow', function (e) {
    if (e.persisted) {
      setRemUnit()
    }
  })

  // detect 0.5px supports
  if (dpr >= 2) {
    var fakeBody = document.createElement('body')
    var testElement = document.createElement('div')
    testElement.style.border = '.5px solid transparent'
    fakeBody.appendChild(testElement)
    docEl.appendChild(fakeBody)
    if (testElement.offsetHeight === 1) {
      docEl.classList.add('hairlines')
    }
    docEl.removeChild(fakeBody)
  }
}(window, document))

<script src="flexible.js" type="text/javascript" charset="utf-8"></script>