hugo-toha/layouts/partials/navigators/theme-selector.html

<li class="nav-item dropdown">
<!-- This is for initializing the color scheme selection for new visitors. See /js/darkmode.js -->
<div id="theme-initialization" style="display: none;"
  default-theme="{{ site.Params.darkMode.default }}"></div>
<a class="nav-link dropdown-toggle"  href="#" id="themeSelector" role="button"
  data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
  <img id="navbar-theme-icon-svg" src="{{ "/icons/moon-svgrepo-com.svg" }}" width=20 alt="Dark Theme">
</a>
<div class="dropdown-menu dropdown-menu-icons-only" aria-labelledby="themeSelector">
  <a class="dropdown-item nav-link" href="#" onclick="enableLightTheme()">
    <img class="menu-icon-center" src="{{ "/icons/sun-svgrepo-com.svg" }}" width=20 alt="Light Theme">
  </a>
  <a class="dropdown-item nav-link" href="#" onclick="enableDarkTheme()">
    <img class="menu-icon-center" src="{{ "/icons/moon-svgrepo-com.svg" }}" width=20 alt="Dark Theme">
  </a>
  <a class="dropdown-item nav-link" href="#" onclick="useSystemTheme()">
    <img class="menu-icon-center" src="{{ "/icons/computer-svgrepo-com.svg" }}" width=20 alt="System Theme">
  </a>
</div>
</li>