code: @Nonnull
    @ReturnsMutableCopy
    public ICommonsList <CSSPageRule> getAllPageRules ()
    {
      return m_aRules.getAllMapped (r -> r instanceof CSSPageRule, r -> (CSSPageRule) r);
    }
docs: Get a list of all top-level rules that are page rules (implementing
  {@link CSSPageRule}).
  
  @return A copy of all contained <code>@page</code> rules. Never
  <code>null</code>.