// 使い方
// +border-radius(vertical, 4px)

=border-radius($value1: null, $value2: null)
  @if number(nth($value1, 1))
    +rem('border-radius', $value1)
  @else
    @for $i from 1 through length($value1)
      @if nth($value1, $i) == 'all'
        +rem('border-radius', $value2)
      @else if vertical(nth($value1, $i))
        +rem('border-top-radius', $value2)
        +rem('border-bottom-radius', $value2)
      @else if horizontal(nth($value1, $i))
        +rem('border-left-radius', $value2)
        +rem('border-right-radius', $value2)
      @else if top(nth($value1, $i))
        +rem('border-top-radius', $value2)
      @else if bottom(nth($value1, $i))
        +rem('border-bottom-radius', $value2)
      @else if left(nth($value1, $i))
        +rem('border-left-radius', $value2)
      @else if right(nth($value1, $i))
        +rem('border-right-radius', $value2)

// 使い方
// +reset-border-radius(vertical, 4px)
=reset-border-radius($value: 'all')
  @for $i from 1 through length($value1)
    @if nth($value1, $i) == 'all'
      border-radius: 0
    @else if vertical(nth($value1, $i))
      border-top-radius: 0
      border-bottom-radius: 0
    @else if horizontal(nth($value1, $i))
      border-left-radius: 0
      border-right-radius: 0
    @else if top(nth($value1, $i))
      border-top-radius: 0
    @else if bottom(nth($value1, $i))
      border-bottom-radius: 0
    @else if left(nth($value1, $i))
      border-left-radius: 0
    @else if right(nth($value1, $i))
      border-right-radius: 0