CSS Style external links

<p>Here is some text and an <a href=http://google.com>absolute link</a>. It's a bit different, no?<p>By comparison, <a href='/'>relative links</a> appear as normal.
a[href ^= 'http']:after { content: ' ' url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAAVklEQVR4Xn3PgQkAMQhDUXfqTu7kTtkpd5RA8AInfArtQ2iRXFWT2QedAfttj2FsPIOE1eCOlEuoWWjgzYaB/IkeGOrxXhqB+uA9Bfcm0lAZuh+YIeAD+cAqSz4kCMUAAAAASUVORK5CYII=);}