// 去掉数值的单位(stripUnits(16px) => 16)
@function stripUnits ($number) {
    @return $number / ($number * 0 + 1);
}

//px转rem, 16px => 1rem
@function toRem($value, $root:$font-size-root) {
    @if (unit($value) != 'rem') {
        $value: stripUnits($value);
    }
    @if ($value == 0) {
        @return 0;
    }
    $root: stripUnits($root);
    @return if($value == 0, 0, $value / $root * 1rem);
}

//多数值转rem(eg. rem(8 16 16 32) => 0.5rem 1rem 1rem 2rem)
@function rem ($values) {
    $results: ();
    $count: length($values);

    @if $count == 1 {
        @return toRem($values);
    }
    @for $i from 1 through $count {
        $results: append($results, toRem(nth($values, $i)));
    }
    @return $results;
}