anchor.diff:                    __Examples__
   
                     `header`, `container`, `menu`, `checkbox`, `input`
  +
               .grid__cell-lg_size_4.grid__cell_left-border
                 .heading.heading_level_1.heading_element Element
                 .raw-text
  
positive.code:             .grid__cell-sm.grid__cell-sm_size_12
                +heading('Introduction', 'introduction')
  
            .grid__row
              .grid__cell-sm.grid__cell-sm_size_12.raw-text
                :markdown
                  On smaller brochure sites, how your organize your styles isn’t usually a big concern. You get in there, write some CSS, or maybe even some SASS. You compile it all into a single stylesheet with SASS’s production settings, and then you aggregate it to get all the stylesheets from modules into a nice tidy package.
  
  
negative.code:           .grid__row
              .grid__cell-sm.grid__cell-sm_size_12.raw-text
                :markdown
                  ## Case study
  
                  We are looking forward to writing "How to migrate existing project to BEM". In meanwhile you can watch nice presentation by Nicole Sullivan — "[CSS preprocessor performance](http://www.youtube.com/watch?v=0NDyopLKE1w)". It gives a very good explanation of problems, that she meets in major of sites and ways to track and handle them.
        .grid__cell-md.grid__cell-md_size_3
          .affix__menu.hidden-xs.hidden-sm(data-spy="affix" data-offset-top="50" data-offset-bottom="200")
            ul.nav.nav_pills.nav_stacked
              - var headings = [];
              - headings.push('Introduction');
              - headings.push('Methodologies');
              - headings.push('Why BEM over the others?');
              - headings.push('Blocks, Elements and Modifiers');
              - headings.push('Under the hood');
              - headings.push('Benefits');
  
              each heading, index in headings
                - var hash = heading.toLowerCase().replace(/,|\./g, '').replace(/\?|\!|\ /g, '-');
                li.nav__item(class= index === 0 ? 'nav__item_active' : '')
                  a.nav__link(href="##{hash}") #{heading}
  