title: Django-Simple-Captcha add CSS
body: <p>Version Python: 3.6.0 and Version Django: 1.10.5</p>
  
  <p>I read all the Documentation about Django-simple-captcha and I just find this sentence to modifie the render of the captcha:</p>
  
  <blockquote>
    <p>(Used to default to: u'%(image)s %(hidden_field)s %(text_field)s')</p>
  </blockquote>
  
  <p><strong>I don't want to change the patern</strong> for all the captchas, <strong>I just need to change the current the captcha</strong> maybe with add <em>attrs={}</em> in the forms.py like the others fields.</p>
  
  <p>Example of regular syntaxe who work:</p>
  
  <pre><code>name = forms.CharField(widget=forms.TextInput(attrs={'class': 'special'}))
  </code></pre>
  
  <p>For the moment, I have something like this <a href="https://i.stack.imgur.com/DHini.png" rel="nofollow noreferrer">Captcha : img + textfield</a> in a render HTML.
  And if it's possible i want something like <a href="https://django-simple-captcha.readthedocs.io/en/latest/_images/captcha3.png" rel="nofollow noreferrer">the documentation</a>.</p>
  
  <p>I use in forms.py:</p>
  
  <pre><code>class RegisterForm(forms.ModelForm):
      ...
      captcha = CaptchaField(label='Are you an human? ')
  </code></pre>
  
  <p>And in the page.html: </p>
  
  <pre><code>&lt;div class="fieldWrapper input-field col-xs-12"&gt;
      &lt;i class="material-icons"&gt;person_pin&lt;/i&gt;
      &lt;label for="id_captcha"&gt;{{ form.captcha.label }}&lt;/label&gt;
      {{ form.captcha }}
  &lt;/div&gt;
  </code></pre>
  
  <p>CaptchaField render is 3 differents fields, the HTML render as default is (code in browser) :</p>
  
  <pre><code>&lt;img src="/captcha/image/f5dc943d14ecb5674a1490468567bcb186178228/" alt="captcha" class="captcha"&gt; 
  &lt;input id="id_captcha_0" name="captcha_0" type="hidden" value="f5dc943d14ecb5674a1490468567bcb186178228"&gt;
  &lt;input autocomplete="off" id="id_captcha_1" name="captcha_1" type="text"&gt;
  </code></pre>
  
  <p>I try to a find the possibility to use the argument "attrs" in the widget captcha to add CSS for text field, like the other Django field. So i try something like that in my form.py :</p>
  
  <pre><code>captcha = CaptchaField(label='Are you an human? ', widget=forms.TextInput(attrs={'class':'white-text'}))
  </code></pre>
  
  <p>But it's did not work because the default field generated by captchafield() was replaced by an other field text field (and the id is wrong for the validation of the captcha or i only have my textfield and not picture).</p>
  
  <p>So I continue search a solution and i try to understand the composition about the structure of CaptchaField :</p>
  
  <pre><code>captcha.__dict__
  {'require_all_fields': True, 'required': True, 'label': 'Are you an human ? ', 'initial': None, 'show_hidden_initial': False, 'help_text': '', 'disabled': False, 'label_suffix': None, 'localize': False, 'widget': &lt;captcha.fields.CaptchaTextInput object at 0x000001F929C16198&gt;, 'creation_counter': 28, 'error_messages': {'required': &lt;django.utils.functional.lazy.&lt;locals&gt;.__proxy__ object at 0x000001F9290A4828&gt;, 'invalid': &lt;django.utils.functional.lazy.&lt;locals&gt;.__proxy__ object at 0x000001F929C16E48&gt;, 'incomplete': &lt;django.utils.functional.lazy.&lt;locals&gt;.__proxy__ object at 0x000001F9290ED080&gt;}, 'validators': [], 'fields': (&lt;django.forms.fields.CharField object at 0x000001F929C16080&gt;, &lt;django.forms.fields.CharField object at 0x000001F929C167B8&gt;)}
  
  captcha.__dict__.keys()
  dict_keys(['require_all_fields', 'required', 'label', 'initial', 'show_hidden_initial', 'help_text', 'disabled', 'label_suffix', 'localize', 'widget', 'creation_counter', 'error_messages', 'validators', 'fields'])
  </code></pre>
  
  <p>So i search to add "attrs" argument in my TextInput Field:</p>
  
  <pre><code>captcha.widget.widgets[1]
  &lt;django.forms.widgets.TextInput object at 0x000001F929C16EB8&gt;
  
  captcha.widget.widgets[1].__dict__
  {'attrs': {}}
  </code></pre>
  
  <p>Now i try to modifie the attrs of field TextInput who construct the render, so i see the <a href="https://docs.djangoproject.com/fr/1.10/ref/forms/widgets/#multiwidget" rel="nofollow noreferrer">MultiWidget</a> who build the 3 fields <a href="https://github.com/mbi/django-simple-captcha/blob/master/captcha/fields.py#L15" rel="nofollow noreferrer">on the doc</a> :</p>
  
  <pre><code>class BaseCaptchaTextInput(MultiWidget):
      """
      Base class for Captcha widgets
      """
      def __init__(self, attrs=None):
          widgets = (
              HiddenInput(attrs),
              TextInput(attrs),
          )
          super(BaseCaptchaTextInput, self).__init__(widgets, attrs)
  </code></pre>