anchor.diff:        :stylus
           .foo
             @import "../src/morph"
  +
  +          h1
  +            margin 1em 20px 0.5em 0
  +            font-family sans-serif
  +            font-weight bold
  +            font-size 36px
  +            font-style italic
  +            line-height 40px
   
             h2
               margin 1em 20px 0.5em 0
  
positive.code:           | .foo address
        +div(class="__after")
          address.div
            | address.div
        +bem(false)
  
      hr
  
negative.code:           | .foo blockquote
        +div(class="__after")
          blockquote.div
            | .foo blockquote.div
        +bem(false)
  
      hr
  