使用django crispy表单自定义非表单错误

我想定制django crispy显示非表单错误的方式。我知道如何更改文本,但我不知道在哪里更改css。

My login area

forms.py

class LoginForm(forms.Form):
    alphanumeric = RegexValidator(r'^[0-9a-zA-Z]*$', 'Only alphanumeric characters are allowed.')
    username = forms.CharField(label='', required=True, widget=forms.TextInput(attrs={'placeholder': 'Username'}))
    password = forms.CharField(label='', required=True, widget=forms.PasswordInput(attrs={'placeholder': 'Password'}))
    name = forms.CharField(label='', 
                        required=True ,  
                        validators=[alphanumeric], 
                        widget=forms.TextInput(attrs={'placeholder': 'Name'}))


    def clean(self):
        username = self.cleaned_data.get('username')
        password = self.cleaned_data.get('password')
        user = authenticate(username=username, password=password)
        if not user or not user.is_active:
            raise forms.ValidationError('Invalid Login : I want to change this CSS')
        return self.cleaned_data

    def login(self, request):
        username = self.cleaned_data.get('username')
        password = self.cleaned_data.get('password')
        user = authenticate(username=username, password=password)
        return user

模板-html

<form method="POST" action="">{% csrf_token %}
    <!--{% if  form.non_field_errors %}
        testing
    {% endif %}-->
    {{form|crispy}}
    <div class="form-info">
        <label class="hvr-sweep-to-right">
            <input class="create btn"  type="submit" value="Submit">
        </label>
    </div>
</form>