@ Nonnull public final HCHead addCSSAt ( @ Nonnegative final int nIndex , @ Nonnull final IHCNode aCSS ) { ValueEnforcer . notNull ( aCSS , "CSS" ) ; if ( ! HCCSSNodeDetector . isCSSNode ( aCSS ) ) throw new IllegalArgumentException ( aCSS + " is not a valid CSS node!" ) ; m_aCSS . add ( nIndex , aCSS ) ; return this ; }
Add a CSS node at the specified index .