pre.highlight {
    position: relative;
    margin: 4px;
    padding: 8px;
    background: #ddd;
    border: 1px solid #bbb;
}

pre.highlight.js::after {
    content: "Javascript";
    position: absolute;
    top: 0;
    right: 0;
    padding: 4px;
    font-variant: small-fonts;
    opacity: .5;
}