=row-size($property, $factor: 1)

  $value : 40px

  // Set property value
  #{$property}: nth($value,1) * $factor

  // Respond to different screen sizes
  /*
    +respond-to(medium)
      #{$property}: nth($value,2) * $factor
    +respond-to(large)
      #{$property}: nth($value,3) * $factor

=row-line-height($factor: 1)
  +row-size(line-height, $factor)

=row-height($factor: 1)
  +row-size(height, $factor)