misc.html

<!-- collapse buttons -->
<script>
  var container = document.querySelector(".sidebar-title");
  var button = document.createElement("button");
  button.style.border = "none";
  button.style.backgroundColor = "unset";
  var icon = document.createElement("i");
  icon.classList = "bi bi-arrows-collapse";
  button.appendChild(icon);

  button.onclick = onbuttonclicked;
  container.appendChild(button);

  function onbuttonclicked() {
    if (icon.classList == "bi bi-arrows-collapse") {
      document.querySelectorAll(
        "a.sidebar-item-toggle:not(.collapsed)"
      ).forEach((x) => x.click());
      icon.classList = "bi bi-arrows-expand";
    } else {
      document.querySelectorAll(
        "a.sidebar-item-toggle.collapsed"
      ).forEach((x) => x.click());
      icon.classList = "bi bi-arrows-collapse";
    }
  }
</script>