layout.html

{% extends "layout.html" %}
{% block body %}
  <h2>Login</h2>
  {% if error %}<p class="error"><strong>Error:</strong> {{ error }}{% endif %}
  <form action="{{ url_for('login') }}" method="post">
    <dl>
      <dt>Username:
      <dd><input type="text" name="username">
      <dt>Password:
      <dd><input type="password" name="password">
      <dd><input type="submit" value="Login">
    </dl>
  </form>
{% endblock %}