-* (document settings) :noexport:
-** use dark style for TWBS-HTML exporter
-#+HTML_HEAD: <link href="https://bootswatch.com/3/darkly/bootstrap.min.css" rel="stylesheet">
-#+HTML_HEAD: <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
-#+HTML_HEAD: <script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/js/bootstrap.min.js"></script>
-#+HTML_HEAD: <style type="text/css">
-#+HTML_HEAD: footer {background-color: #111 !important;}
-#+HTML_HEAD: pre {background-color: #111; color: #ccc;}
-#+HTML_HEAD: </style>
-