Link out symbol

I have been looking for a wikipedia-style link out symbol (wikipedia uses a svg symbol). Some websites recommend font awesome symbol /f08e others are in favor of the north east arrow #x2197; while I modfied now a code pen by thiago for the css of this wordpress child theme

  a:not([href*=''])::after {
    content: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAAQElEQVR42qXKwQkAIAxDUUdxtO6/RBQkQZvSi8I/pL4BoGw/XPkh4XigPmsUgh0626AjRsgxHTkUThsG2T/sIlzdTsp52kSS1wAAAABJRU5ErkJggg==);
    margin: 0 3px 0 5px;