Stylus mixins

_mixin.styl

ds(w,h = auto,f = left)
  width w
  height h
  float f

lh(n)
  line-height (n * 100)%

fs(c,fz,lh,fw = 400)
  color c
  font-size fz
  line-height (lh * 100)%
  font-weight fw

opa(o,t = 0.25)
  opacity o
  transition t

marginTop(t-baseMargin = 20px, t-FontSize = 14px, t-LineHeight = 22px)
  margin-top (t-baseMargin - ((t-LineHeight - t-FontSize) / 2))

marginBottom(b-baseMargin = 20px, b-FontSize = 14px, b-LineHeight = 22px)
  margin-bottom (t-baseMargin - ((t-LineHeight - t-FontSize) / 2))