pip install django-suit

# settings.py
from django.conf.global_settings import TEMPLATE_CONTEXT_PROCESSORS as TCP

TEMPLATE_CONTEXT_PROCESSORS = TCP + (
'django.core.context_processors.request',
)

python manage.py makemigrations
python manage.py migrate
python manage.py collectstatic

SuitDateWidget, SuitTimeWidget and SuitSplitDateTimeWidget extends original admin widgets by adding some additional output styling only. Widgets still uses same original JavaScript for calendar and time. You can see example in Demo app: User changeform:

from django.forms import ModelForm
from suit.widgets import SuitDateWidget, SuitTimeWidget, SuitSplitDateTimeWidget

class UserChangeForm(UserChangeForm):
    class Meta:
        model = User
        widgets = {
            'last_login': SuitSplitDateTimeWidget,
            'date_joined': SuitSplitDateTimeWidget,
        }