embedded koha login form

<form action="https://oiva.vaarakirjastot.fi/cgi-bin/koha/opac-user.pl" method="post" name="auth" id="auth">
  <input type="hidden" name="koha_login_context" value="opac">

  <fieldset class="brief">
    <legend>Log in to your account:</legend>
    <label for="userid">Login:</label><input type="text" id="userid" name="userid">
    <label for="password">Password:</label><input type="password" id="password" name="password">
    <fieldset class="action">
      <input type="submit" value="Log in" class="btn">
    </fieldset>

  </fieldset>
</form>