anchor.diff:  
   li.button_topnav {
       float: right;
  -    background-color: white;
  +    background-color: purple;
   }
   
   li a {
  
positive.code:     </div>
    </font>
  
    <% if current_user %>
    <div>
      <form action='/sessions' method ='post'>
        <input type='hidden' name='_method' value='delete'>
        <input type='submit' value='Sign Out'>
      </form>
    </div>
    <% end %>
    <%= yield %>
  
  </body>
  
negative.code:           </form>
        </a>
      </li>
      <% if current_user === false %>
      <li class="button_topnav">
        <a>
          <form action="/signin" >
  