代码（移动端rem初始化设置1rem=15px）

@media (min-width: 240px) and (max-width:320px) {
  html {
      font-size:12.8px!important
  }
}

@media (min-width: 321px) and (max-width:360px) {
  html {
      font-size:14.4px!important
  }
}

@media (min-width: 361px) and (max-width:375px) {
  html {
      font-size:15px!important
  }
}

@media (min-width: 376px) and (max-width:384px) {
  html {
      font-size:15.36px!important
  }
}

@media (min-width: 385px) and (max-width:414px) {
  html {
      font-size:16.56px!important
  }
}

@media (min-width: 415px) and (max-width:450px) {
  html {
      font-size:18px!important
  }
}

@media (min-width: 451px) and (max-width:500px) {
  html {
      font-size:20px!important
  }
}

@media (min-width: 501px) and (max-width:550px) {
  html {
      font-size:22px!important
  }
}

@media (min-width: 551px) and (max-width:569px) {
  html {
      font-size:22.72px!important
  }
}

@media (min-width: 569px) and (max-width:640px) {
  html {
      font-size:25.6px!important
  }
}

@media (min-width: 641px) and (max-width:667px) {
  html {
      font-size:26.68px!important
  }
}

@media (min-width: 668px) and (max-width:736px) {
  html {
      font-size:29.44px!important
  }
}

@media (min-width: 738px) and (max-width:768px) {
  html {
      font-size:30.72px!important
  }
}

@media (min-width: 769px) and (max-width:900px) {
  html {
      font-size:36px!important
  }
}

@media (min-width: 901px) and (max-width:1080px) {
  html {
      font-size:43.24px!important
  }
}

@media (min-width: 393px) and (max-width:395px) {
  html {
      font-size:15.8px!important
  }
}

@media (min-width: 392px) and (max-width:392px) {
  html {
      font-size:15.68px!important
  }
}

@media (min-width: 432px) and (max-width:432px) {
  html {
      font-size:17.28px!important
  }
}