a[target="_blank"]::after{content:"";display:inline-block;width:12px;height:12px;background-image:url(https://uxdesign.com/images/new-window-icon.svg);background-size:contain;background-repeat:no-repeat;margin-left:5px;filter:invert(0)}.wp-block-button__link[target="_blank"]::after{filter:invert(1) brightness(1.2)}