code: func (inliner *Inliner) insertRawStylesheet() {
  	rawCSS := inliner.computeRawCSS()
  	if rawCSS != "" {
  		// create <style> element
  		cssNode := &html.Node{
  			Type: html.TextNode,
  			Data: "\n" + rawCSS,
  		}
  
  		styleNode := &html.Node{
  			Type: html.ElementNode,
  			Data: "style",
  			Attr: []html.Attribute{{Key: "type", Val: "text/css"}},
  		}
  
  		styleNode.AppendChild(cssNode)
  
  		// append to <head> element
  		headNode := inliner.doc.Find("head")
  		if headNode == nil {
  			// @todo Create head node !
  			panic("NOT IMPLEMENTED: create missing <head> node")
  		}
  
  		headNode.AppendNodes(styleNode)
  	}
  }
docs: // Insert raw CSS rules into HTML document