Showing nested pages

HTML

<nav class="dwp-side-navigation" aria-label="Side" role="navigation">
  <ul class="dwp-side-navigation__list">
    <li class="dwp-side-navigation__item">
      <a id="sn-item-1" href="#sn-item-1" class="dwp-side-navigation__link">
        Item 1
      </a>
    </li>
    <li class="dwp-side-navigation__item dwp-side-navigation__item--selected">
      <a id="sn-item-2" href="#sn-item-2" class="dwp-side-navigation__link dwp-side-navigation__link--selected" aria-current="true">
        Item 2
      </a>
      <ul class="dwp-side-navigation__list dwp-side-navigation__list--sub-item">
        <li class="dwp-side-navigation__sub-item">
          <a id="s-sn-item-1" href="#s-sn-item-1" class="dwp-side-navigation__link">
            subitem 1
          </a>
        </li>
        <li class="dwp-side-navigation__sub-item">
          <a id="s-sn-item-2" href="#s-sn-item-2" class="dwp-side-navigation__link">
            subitem 2
          </a>
        </li>
        <li class="dwp-side-navigation__sub-item">
          <a id="s-sn-item-3" href="#s-sn-item-3" class="dwp-side-navigation__link">
            subitem 3
          </a>
        </li>
      </ul>
    </li>
    <li class="dwp-side-navigation__item">
      <a id="sn-item-3" href="#sn-item-3" class="dwp-side-navigation__link">
        Item 3
      </a>
    </li>
    <li class="dwp-side-navigation__item">
      <a id="sn-item-4" href="#sn-item-4" class="dwp-side-navigation__link">
        Item 4
      </a>
    </li>
    <li class="dwp-side-navigation__item">
      <a id="sn-item-5" href="#sn-item-5" class="dwp-side-navigation__link">
        Item 5
      </a>
    </li>
  </ul>
</nav>