@mixin font($num) {
  .font-#{$num}
    {
      font-size:#{$num}px;
    }
}

@for $i from 8 through 50
{
    @include font($i*2)
}

/*
  增加需要的数值
  (width height)
*/
$defaultFontSizeArray: 70,80,100;


@each $i in $defaultFontSizeArray{
  @include font($i)
}