Links not working Django -

in base.html links on nav bar not working reason. i've wrote correctly, when hover on link doesn't anything.

<ul class="nav navbar-nav navbar-right">                     <li class="active" role="presentation" data-aos="fade-down" data-aos-duration="900"><a href="{% url 'register' %}"><strong>join us?</strong></a></li>                     <li class="active" role="presentation" data-aos="fade-down" data-aos-duration="900"><a href="{% url 'login'%}"><strong>log in</strong></a></li> 

urls.py

url('^delta/$', aircraft_delta, name='aircraft_delta'),  #aircraft/detail/1 url('^aircraft/detail/(?p<id>\d+)/$', aircraft_detail, name='aircraft_detail'),  #aircraft/ url(r'^aircraft/$', list_aircraft, name='aircraft_home'),  #login/ url(r'^login/', login_view, name="login"),  #logout/ url(r'^logout/', logout_view, name="logout"),  #register/ url(r'^register/', register_view, name="register"),  #upload/aircraft url(r'^upload/aircraft/$', aircraft_create), 

root urls.py

urlpatterns = [     url(r'^admin/', admin.site.urls),     url(r'^accounts/', include('accounts.urls')),     url(r'^', include('aircraft.urls')),]