code: @Nonnull
    public CSSMediaRule addMediaQuery (@Nonnegative final int nIndex, @Nonnull @Nonempty final CSSMediaQuery aMediaQuery)
    {
      ValueEnforcer.isGE0 (nIndex, "Index");
      ValueEnforcer.notNull (aMediaQuery, "MediaQuery");
  
      if (nIndex >= getMediaQueryCount ())
        m_aMediaQueries.add (aMediaQuery);
      else
        m_aMediaQueries.add (nIndex, aMediaQuery);
      return this;
    }
docs: Add a media query at the specified index.
  
  @param nIndex
  The index to use. Must be &ge; 0. If the index is &ge;
  {@link #getMediaQueryCount()} than the media query is appended like
  in {@link #addMediaQuery(CSSMediaQuery)}.
  @param aMediaQuery
  The media query to be added. May not be <code>null</code>.
  @return this for chaining