Stylus: Image replacement mixin

classses.styl

// Image replacement
ir()
	width = arguments ? arguments[0] : 100%
	height = arguments && arguments[1] ? arguments[1] : false
	height = height ? height : width

	direction ltr
	display block
	height height
	overflow hidden
	text-align left
	text-indent 100%
	white-space nowrap
	width width

.ir
	ir()

site.styl

@import "classes"

#ad
	@extends .ir

#banners a
	ir(400, 100)