igation">
            <span class="navbar-toggler-icon"></span>
        </button>
        {% endif %}
        {% assign fixed_links = include.fixed | default: include.nav.fixed | default: site.data.index.nav.fixed %}
        {% for link in fixed_links %}
        {% include link.html link=link class="btn nav-item mt-1" %}
        {% endfor %}

        {% if colab %}
        {% comment %}
        <!--todo: add automatic table of content for notebooks-->
        <!--<button class="nav-link btn">-->
        <!-