anchor.diff:                         class: 'btn btn-outline-success my-2 my-sm-0' %>
         <% end %>
       <% end %>
  -  </div>
   </nav>
  
positive.code: <nav class="navbar navbar-expand-md navbar-dark bg-dark">
    <%= image_tag '/MaMpf-Logo_32x32.png',
                  class: 'img-fluid mr-2' %>
    <%= link_to "MaMpf", root_path,
  
negative.code:     <span class="navbar-toggler-icon">
      </span>
    </button>
      <ul class="navbar-nav mr-auto">
        <% if user_signed_in? %>
          <li class="nav-item">
  