Untitled

dabblet.css

.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;
}

dabblet.html

<div class="inner-border">
    Transparent Inside Border
</div>

dabblet.js

// alert('Hello world!');

settings.json

{"view":"split","fontsize":"100","seethrough":"","prefixfree":"1","page":"result"}