nav[data-toggle="toc"] {
    top: 42px;
}

nav[data-toggle="toc"] .nav-link + ul {
    display: block;
}

/* small screens */
@media (max-width: 768px) {

    /* override stickyness so that the navigation does not follow scrolling */
    nav[data-toggle="toc"] {
        margin-bottom: 42px;
        position: static;
    }

    /* PICK ONE */
    /* don't expand nested items, which pushes down the rest of the page when navigating */
    nav[data-toggle="toc"] .nav .active .nav {
        display: none;
    }

    /* alternatively, if you *do* want the second-level navigation to be shown (as seen on this page on mobile), use this */
    /*
    nav[data-toggle='toc'] .nav .nav {
      display: block;
    }
    */
}