def build_tree
      root = Sass::SCSS::CssParser.new(@template, @options[:filename], nil).parse
      parse_selectors(root)
      expand_commas(root)
      nest_seqs(root)
      parent_ref_rules(root)
      flatten_rules(root)
      bubble_subject(root)
      fold_commas(root)
      dump_selectors(root)
      root
    end
def build_tree
      root = Sass::SCSS::CssParser.new(@template, @options[:filename], nil).parse
      parse_selectors(root)
      expand_commas(root)
      nest_seqs(root)
      parent_ref_rules(root)
      flatten_rules(root)
      bubble_subject(root)
      fold_commas(root)
      dump_selectors(root)
      root
    end
Parses the CSS template and applies various transformations

 @return [Tree::Node] The root node of the parsed tree