SOCIAL_AUTH_FACEBOOK_KEY = 'Client ID'
SOCIAL_AUTH_FACEBOOK_SECRET = 'Client Secret'

AUTHENTICATION_BACKENDS = (
    ...
    'social_core.backends.facebook.FacebookOAuth2',
)

SOCIAL_AUTH_FACEBOOK_SCOPE = ['email'] #Only upon Facebook verification, otherwise will generate login error

<style>

  #fb_button{
    background-color:#385499;
    width:100%;
    margin-bottom:10px;
    border: 1px solid #385499;
    border-radius: 5px !important;
    -webkit-box-shadow: 1px 1px 9px 0px rgba(190, 190, 190, 0.5);
    -moz-box-shadow:    1px 1px 9px 0px rgba(190, 190, 190, 0.5);
    box-shadow:         1px 1px 9px 0px rgba(190, 190, 190, 0.5);
  }

  #fb_button:hover{
    background-color:#2f4782;
  }

</style>


<a id="fb_button" class="btn btn-primary" href="{% url 'social:begin' 'facebook' %}">Login with Facebook</a>