@mixin shadow($z) {
	@if $z == 1 {
		box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
	}

	@else if $z == 2 {
		box-shadow: 0 3px 6px rgba(0,0,0,0.16), 0 3px 6px rgba(0,0,0,0.23);
	}

	@else if $z == 3 {
		box-shadow: 0 10px 20px rgba(0,0,0,0.19), 0 6px 6px rgba(0,0,0,0.23);
	}

	@else if $z == 4 {
		box-shadow: 0 14px 28px rgba(0,0,0,0.25), 0 10px 10px rgba(0,0,0,0.22);
	}

	@else if $z == 5 {
		box-shadow: 0 19px 38px rgba(0,0,0,0.30), 0 15px 12px rgba(0,0,0,0.22);
	}

	@else if $z == -1 {
		box-shadow: inset 0 -1px 3px rgba(0,0,0,0.12), inset 0 -1px 2px rgba(0,0,0,0.24);
	}

	@else {
		@warn "#{$z} is not a valid value for shadow depth"
	}
}