Vertical InRitsu Mixin inspired Vertical Rhythm and Modular Scale

_mixin_vertical-inritsu.sass

//============================================================
// Vertical InRitsu Mixin inspired Vertical Rhythm and Modular Scale
// NOTICE: need to load pow function before
//         ref: https://css-tricks.com/snippets/sass/power-function/
//============================================================
=vertical-inritsu($in-scale: 0, $with-margin-top: 1, $with-margin-bottom: 1, $with-padding-top: 0, $with-padding-bottom: 0)
  $base-font-size: 1rem !default
  $base-ratio: 1.414 !default
  $in-fz: $base-font-size * pow($base-ratio, ($in-scale / 4))
  $in-base-unit: ($base-font-size * pow($base-ratio, 2)/ 4)
  $in-lh: $in-base-unit
  @while ($in-lh - $in-fz) < $in-base-unit
    $in-lh: $in-lh + $in-base-unit
  font-size: $in-fz
  line-height: $in-lh
  margin-top: ($in-base-unit * 4) * $with-margin-top
  margin-bottom: ($in-base-unit * 4) * $with-margin-bottom
  padding-top: ($in-base-unit * 4) * $with-padding-top
  padding-bottom: ($in-base-unit * 4) * $with-padding-bottom