_vertical-rhythm.scss

$base-font-size: 1rem !global;
$base-line-height: $base-font-size * 1.5 !global;
$round-to-nearest-half-line: true !global;

/**
 * Convert a unitless value to vertical rhythm units.
 * Non-unitless numbers are ignored.
 * @param  {number | list} $values - Number of lines
 * @return {number | list} Output
 */
@function rhythm($value) {
  @if type-of($value) == list {
    $list: $value;
    $separator: list-separator($list);
    $rhythm: ();

    @each $item in $list {
      $rhythm: append($rhythm, rhythm($item), $separator);
    }

    @return $rhythm;
  }

  @else if type-of($value) == number and unit($value) == "" and $value != 0 {
    $lines: $value;
    $value: $lines * $base-line-height;
  }

  @return $value;
}