Sass remify/emify mixins

_unit.scss

// Defaults
$base_font_size: 16px;
$rem_fallback: true;

// Usage: rem(16px);
@function rem(
  $size,
  $base_font_size: $base_font_size
) {
  @return #{$size / $base_font_size}rem;
}

// Usage: em(16px);
@function em(
  $size,
  $base_font_size: $base_font_size
) {
  @return #{$size / $base_font_size}em;
}

// Usage: @include remify(font-size, 16px);
@mixin remify(
	$property,
	$size,
	$rem_fallback: $rem_fallback,
	$base_font_size: $base_font_size
) {
	@if $rem_fallback {
		#{$property}: $size;
	}
	#{$property}: rem($size, $base_font_size);
}

// Usage: @include emify(font-size, 16px);
@mixin emify(
	$property,
	$size,
	$base_font_size: $base_font_size
) {
  #{$property}: em($size, $base_font_size);
}