!default_box_shadow_color = #333
!default_box_shadow_x_offset = 1px
!default_box_shadow_y_offset = 1px
!default_box_shadow_blur_radius = 8px

=box-shadow(!color = !default_box_shadow_color, !blur_radius = !default_box_shadow_blur_radius, !x_offset = !default_box_shadow_x_offset, !y_offset = !default_box_shadow_y_offset, !inset = "")
  box-shadow= !inset !x_offset !y_offset !blur_radius !color
  -webkit-box-shadow= !inset !x_offset !y_offset !blur_radius !color
  -moz-box-shadow= !inset !x_offset !y_offset !blur_radius !color

=inset-box-shadow(!color = !default_box_shadow_color, !blur_radius = !default_box_shadow_blur_radius, !x_offset = !default_box_shadow_x_offset, !y_offset = !default_box_shadow_y_offset)
  +box-shadow(!color, !blur_radius, !x_offset, !y_offset, "inset")