def extract_css
      stylesheets = @dom.css(STYLE_ELEMENT_QUERY).map { |element|
        stylesheet = read_stylesheet(element)
        element.remove if stylesheet
        stylesheet
      }.compact
      stylesheets
    end
def extract_css
      stylesheets = @dom.css(STYLE_ELEMENT_QUERY).map { |element|
        stylesheet = read_stylesheet(element)
        element.remove if stylesheet
        stylesheet
      }.compact
      stylesheets
    end
Looks for all non-ignored stylesheets, removes their references from the
 DOM and then returns them.

 This will mutate the DOM tree.

 The order of the array corresponds with the document order in the DOM.

 @see #find_css
 @return [Enumerable<Stylesheet>] every extracted stylesheet