code: public static boolean canWrapInMediaQuery (@Nullable final CascadingStyleSheet aCSS,
                                               final boolean bAllowNestedMediaQueries)
    {
      if (aCSS == null)
        return false;
      if (bAllowNestedMediaQueries)
        return true;
      // Nested media queries are not allowed, therefore wrapping can only take
      // place if no other media queries are present
      return !aCSS.hasMediaRules ();
    }
docs: Check if the passed CSS can be wrapped in an external media rule.
  
  @param aCSS
  The CSS to be checked for wrapping. May be <code>null</code>.
  @param bAllowNestedMediaQueries
  if <code>true</code> nested media queries are allowed,
  <code>false</code> if they are prohibited.
  @return <code>true</code> if the CSS can be wrapped, <code>false</code> if
  it can't be wrapped.