<filename>mysite/forms.py
from django import forms


class ContactForm(forms.Form):
    name = forms.CharField(max_length=30)
    email = forms.EmailField(max_length=254)
    message = forms.CharField(
        max_length=2000,
        widget=forms.Textarea(),
        help_text='Write here your message!'
    )
    source = forms.CharField(
        max_length=50,
        widget=forms.HiddenInput()
    )

    def clean(self):
        cleaned_data = super(ContactForm, self).clean()
        name = cleaned_data.get('name')
        email = cleaned_data.get('email')
        message = cleaned_data.get('message')
        if not name and not email and not message:
            raise forms.ValidationError('You have to write something!')


class ColorfulContactForm(forms.Form):
    name = forms.CharField(
        max_length=30,
        widget=forms.TextInput(
            attrs={
                'style': 'border-color: blue;',
                'placeholder': 'Write your name here'
            }
        )
    )
    email = forms.EmailField(
        max_length=254,
        widget=forms.TextInput(attrs={'style': 'border-color: green;'})
    )
    message = forms.CharField(
        max_length=2000,
        widget=forms.Textarea(attrs={'style': 'border-color: orange;'}),
        help_text='Write here your message!'
    )

<filename>mysite/forms.py
from django import forms


class ContactForm(forms.Form):
    name = forms.CharField(max_length=30)
    email = forms.EmailField(max_length=254)
    message = forms.CharField(
        max_length=2000,
        widget=forms.Textarea(),
        help_text='Write here your message!'
    )
    source = forms.CharField(
        max_length=50,
        widget=forms.HiddenInput()
    )

    def clean(self):
        cleaned_data = super(ContactForm, self).clean()
        name = cleaned_data.get('name')
        email = cleaned_data.get('email')
        message = cleaned_data.get('message')
        if not name and not email and not message:
            raise forms.ValidationError('You have to write something!')


class ColorfulContactForm(forms.Form):
    name = forms.CharField(
        max_length=30,
        widget=forms.TextInput(
            attrs={
                'style': 'border-color: blue;',
                'placeholder': 'Write your name here'
            }
        )
    )
    email = forms.EmailField(
        max_length=254,
        widget=forms.TextInput(attrs={'style': 'border-color: green;'})
    )
    message = forms.CharField(
        max_length=2000,
        widget=forms.Textarea(attrs={'style': 'border-color: orange;'}),
        help_text='Write here your message!'
    )
