anchor.diff:                - var cn = { 'Nav-link--active': isSelf || isInCollection };
                 li.Nav-item
                   a.Nav-link(href=url, class=cn)= page.title
  -    - var isArticle = contains(collection, 'articles');
  -    - var isWork = contains(collection, 'work');
  -    - var isTalk = contains(collection, 'talks');
  -    - var isCollection = isArticle || isWork || isTalk;
       main.Article(role="main")
         .Article-section
           h1.Article-h1= title
  
positive.code: doctype html
  html(lang="en")
    head
  
negative.code:     meta(
        name="author"
        content=site.author)
      - var pubdate = date || startDate;
      if pubdate
        meta(
          name="date"
          content=pubdate)
      - var titles = hide_title ? [] : [title];
      if client
        - titles.push(client);
  