Borde interior transparente - Trucos CSS

Anonim
 Transparent Inside Border 
.inner-border ( background: #000; color: #fff; margin: 50px; padding: 15px; position: relative; ) .inner-border:before ( border: 5px solid #000; content: ""; position: absolute; top: -10px; bottom: -10px; left: -10px; right: -10px; )