Sass Vertical Rhythm @Mixins using REM

Vertical_Rythm_mixins.scss

//===========================
// typographic scale and rem:
//===========================

// This @mixins will give fallback in pixels for browsers that don´t support REM

// Line-height and Base font-size:
$line-height: 1.6; 
$base-font: 1rem;

// Font-size mixin:
@mixin font-size($size: 1, $line: $size * 1.6){
  font-size     : ($size * 16) + px;
  line-height   : ($line * 16) + px;
  font-size     : $size + rem;
  line-height   : $line + rem;
}

// Bottom margin @mixin:
@mixin margin-bottom($margin: 1.6) {
  margin-bottom: ($margin * 16) + px;
  margin-bottom: $margin + rem;
}

// Top margin @mixin:
@mixin margin-top($margin: 1.6) {
  margin-top: ($margin * 16) + px;
  margin-top: $margin + rem;
}

// Paragraph @mixin:
@mixin margin-para($margin: 1.6) {
  margin-top: ($margin * 16) + px;
  margin-bottom: ($margin * 16) + px;
  margin-top: $margin + rem;
  margin-bottom: $margin + rem;
}


// Usage example:
/*
h1{ @include font-size(2.488);@include margin-top}  
h2{ @include font-size(2.16);@include margin-top;} 
h3{ @include font-size(1.5);@include margin-top}
h4{ @include font-size(1.2);@include margin-top}
h5{ @include font-size(1);@include margin-top}
h6{ @include font-size(0.833);@include margin-top}

p{ 
  @include font-size(1); 
  @include margin-para;
  word-wrap: break-word;
} 
*/