<hbox>
    <style>
        .Tab {
            padding: 0.5em 1em;
            border-bottom: solid 2px transparent;
            cursor: pointer;
            opacity: 0.6;
        }
        .Tab[selected='true'] {
            border-bottom: solid 2px Highlight;
            opacity: 1;
        }
    </style>
    <hbox flex="1" anon-id="container"></hbox>
</hbox>
