移动端适配（无限适配）

1. <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
2. 关于这种做法的具体实现，淘宝已经给我们提供了一个开源的解决方案，具体请查看： https://github.com/amfe/lib-flexible

(function flexible(window, document) {
    
    
  var docEl = document.documentElement
  var dpr = window.devicePixelRatio || 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() {
    
    
    var rem = docEl.clientWidth / 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))

3. 计算方式：UI图750px 除以 2 除以37.5
4. 或者使用vscode编辑器安装插件cssrem进行自动转换