文字大小自适应

html,body{
  font-size: 10px;
}
@media screen and (min- 319px) {
  html,
  body {
    font-size: 12px;
  }
}
@media screen and (min- 359px) {
  html,body{
    font-size: 13px;
  }

}
@media screen and (min- 374px) {
  html,
  body {
    font-size: 14px;
  }
}
@media screen and (min- 410px) {
  html,body{
    font-size: 15px;
  }
}
@media screen and (min- 434px) {
  html,
  body {
    font-size: 16px;
  }
}
@media screen and (min- 559px) {
  html,
  body {
    font-size: 21px;
  }
}

@media screen and (min- 613px) {
  html,body{
    font-size: 23px;
  }
}
@media screen and (min- 639px) {
  html,
  body {
    font-size: 24px;
  }
}
@media screen and (min- 719px) {
  html,
  body {
    font-size: 27px;
  }
}
@media screen and (min- 739px){
  html,body{
    font-size: 28px;
  }
}

@media screen and (min- 767px) {
  html,
  body {
    font-size: 29px;
  }
}

@media screen and (min- 819px){
  html,body{
    font-size: 31px;
  }
}
@media screen and (min- 939px){
  html,body{
    font-size: 33px;
  }
}

@media screen and (min- 959px) {
  html,
  body {
    font-size: 36px;
  }
}

@media screen and (min- 979px){
  html,body{
    font-size: 38px;
  }

}
@media screen and (min- 1079px) {
  html,body{
    font-size: 40px;
  }
}
@media screen and (min- 1241px){
  html,body{
    font-size: 46px;
  }
}

$designPageWidth: 375;

$pageWidthVSfontSize: 14;

@function trans($px) {
  @return ( $px * $pageWidthVSfontSize / $designPageWidth) * 1rem;
}