py_task/ya_news/templates/includes/header.html

<header>
  <nav class="navbar navbar-light" style="background-color: lightskyblue">
    <li class="container">
      <a class="navbar-brand" href="{% url 'news:home' %}">
        <span class="text-danger"><b>Ya</b></span>News
      </a>
      <ul class="nav nav-pills">
        {% if user.is_authenticated %}
          <li class="align-self-center">
            Пользователь: {{ user.username }}
          </li>
          <li class="nav-item">
            <a class="nav-link" href="{% url 'users:logout' %}">Выйти</a>
          </li>
        {% else %}
          <li class="nav-item">
            <a class="nav-link" href="{% url 'users:login' %}">Войти</a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="{% url 'users:signup' %}">Регистрация</a>
          </li>
        {% endif %}
      </ul>
    </li>
  </nav>
</header>