anchor.diff:            <%= link_to 'Upload', new_picture_path, class: 'nav-link' %>
           </li>
           <% unless %w(home search).include? content_for(:page) %>
  -          <li class="nav-item ml-md-2 mt-md-0 mt-2">
  +          <li class="nav-item ml-md-2 my-md-0 my-2">
               <%= render 'layouts/search' %>
             </li>
           <% end %>
  -      </ul>
   
  -      <ul class="navbar-nav ml-auto mt-md-0 mt-2">
           <% if user_signed_in? %>
  -          <li class="nav-item dropdown">
  +          <li class="nav-item ml-md-auto dropdown">
               <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" style="line-height:30px;padding:5px 0">
                 <% if current_user.avatar? %>
                   <%= image_tag(current_user.avatar.thumb_url('60x60'), alt: 'avatar', class: 'rounded-circle', width: 30, height: 30) %>
  
positive.code: <nav class="navbar navbar-expand-md mb-3 <%= content_for(:page) == 'home' ? 'navbar-dark' : 'navbar-light bg-light' %>">
    <div class="container">
      <a class="navbar-brand" href="/"><%= fa_icon("camera") %> Picture</a>
  
      <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
      </button>
  
      <div class="collapse navbar-collapse" id="navbarNav">
        <ul class="navbar-nav">
          <li class="nav-item<%= ' active' if content_for(:page) == 'explore' %>">
            <%= link_to 'Explore', explore_path, class: 'nav-link' %>
          </li>
  
negative.code:             </div>
            </li>
          <% else %>
            <li class="nav-item ml-md-auto">
              <%= link_to 'Sign in', new_user_session_path, class: 'nav-link' %>
            </li>
            <% unless content_for(:page) == 'home' %>
              <li class="nav-item ml-md-2">
                <%= link_to 'Sign up', new_user_registration_path, class: 'btn btn-outline-primary', role: 'button' %>
              </li>
            <% end %>
          <% end %>
        </ul>
      </div>
  