Append CSS class to form field - django-templates

Question

Once a field has been rendered {{ field|add_class }} how can you add additional classes? For example, let's say you want to build a variable and simply apply that. See the example below.
If field.type = Select
CSSSTYLES += 'form-select'
If field.error
CSSSTYLES += 'error'
{{ field|append_attr:"class:CSSSTYLES" }}
<form class="mt-3" method="POST" action="{% url 'profile' %}" autocomplete="off" novalidate>
{% csrf_token %}
{% for hidden in form.hidden_fields %}
{{ hidden }}
{% endfor %}
{% for field in form.visible_fields %}
<div class="mb-3">
<label class="form-label" id="{{ field.id_for_label }}">
{{ field.label }}
</label>
{% if field.errors %}
{{ field|append_attr:"class:form-control is-invalid is-invalid-lite" }}
{% for error in field.errors %}
<div class="alert alert-danger">
<strong>{{ error|escape }}</strong>
</div>
{% endfor %}
{% else %}
{{ field|append_attr:"class:form-control" }}
{% endif %}
{% endfor %}

Answer 1

{% for field in form.visible_fields %}
<div class="mb-3">
<label class="form-label" id="{{ field.id_for_label }}">
{{ field.label }}
</label>
{% if field.errors %}
{% if field.field.widget.input_type == 'select' %}
{{ field|add_class:"form-select is-invalid is-invalid-lite" }}
{% else %}
{{ field|add_class:"form-control is-invalid is-invalid-lite" }}
{% endif %}
{% for error in field.errors %}
<div class="alert alert-danger">
<strong>{{ error|escape }}</strong>
</div>
{% endfor %}
{% else %}
{% if field.field.widget.input_type == 'select' %}
{{ field|append_attr:"class:form-select" }}
{% else %}
{{ field|append_attr:"class:form-control" }}
{% endif %}
{% endif %}
{% endfor %}