units.scss

$browser-context: 16px !default;

@function strip-unit($num) {
  @return $num / ($num * 0 + 1);
}

@function convert-to-rem($value, $base-value: $browser-context) {
  // stylelint-disable length-zero-no-unit
  $value: strip-unit($value) / strip-unit($base-value) * 1rem;

  @if ($value == 0rem) { $value: 0; } // Turn 0rem into 0

  @return $value;
}

@function rem($values, $base-value: $browser-context) {
  $max: length($values);

  @if $max == 1 {
    @return convert-to-rem(nth($values, 1), $base-value);
  }

  $rem-values: ();

  @for $i from 1 through $max {
    $rem-values: append($rem-values, convert-to-rem(nth($values, $i), $base-value));
  }

  @return $rem-values;
}

@function em($pixels, $context: $browser-context) {
  @if (unitless($pixels)) {
    $pixels: $pixels * 1px;
  }

  @if (unitless($context)) {
    $context: $context * 1px;
  }

  @return $pixels / $context * 1em;
}