[Form] add tailwindcss form theme docs

form/tailwindcss.rst

@@ -0,0 +1,95 @@
+Tailwind CSS Form Theme
+=======================
+
+Symfony provides a minimal form theme for `Tailwind CSS`_. Tailwind is a *utility first*
+CSS framework and provides *unlimited ways* to customize your forms. Tailwind has
+an official `form plugin`_ that provides a basic form reset that standardizes their look
+on all browsers. This form theme requires this plugin and adds a few basic tailwind
+classes so out of the box, your forms will look decent. Customization is almost always
+going to be required so this theme makes that easy.
+
+.. image:: /_images/form/tailwindcss-form.png
+   :align: center
+
+To use, first be sure you have installed and integrated `Tailwind CSS`_ and the
+`form plugin`_. Follow their respective documentation to install both packages.
+
+If you prefer to use the Tailwind theme on a form by form basis, include the
+``form_theme`` tag in the templates where those forms are used:
+
+.. code-block:: html+twig
+
+    {# ... #}
+    {# this tag only applies to the forms defined in this template #}
+    {% form_theme form 'tailwind_2_layout.html.twig' %}
+
+    {% block body %}
+        <h1>User Sign Up:</h1>
+        {{ form(form) }}
+    {% endblock %}
+
+Customization
+-------------
+
+Customizing CSS classes is especially important for this theme.
+
+Twig Form Functions
+~~~~~~~~~~~~~~~~~~~
+
+You can customize classes of individual fields by setting some class options.
+
+.. code-block:: twig
+
+    {{ form_row(form.title, {
+        row_class: 'my row classes',
+        label_class: 'my label classes',
+        error_item_class: 'my error item classes',
+        widget_class: 'my widget classes',
+        widget_disabled_class: 'my disabled widget classes',
+        widget_errors_class: 'my widget with error classes',
+    }) }}
+
+When customizing the classes this way the defaults provided by the theme
+are *overridden* opposed to merged as is the case with other themes. This
+enables you to take full control of the classes without worrying about
+*undoing* the generic defaults the theme provides.
+
+Project Specific Form Layout
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+If you have a generic Tailwind style for all your forms, you can create
+a custom form theme using the Tailwind CSS theme as a base.
+
+.. code-block:: twig
+
+    {% use 'tailwind_2_layout.html.twig' %}
+
+    {%- block form_row -%}
+        {%- set row_class = row_class|default('my row classes') -%}
+        {{- parent() -}}
+    {%- endblock form_row -%}
+
+    {%- block widget_attributes -%}
+        {%- set widget_class = widget_class|default('my widget classes') -%}
+        {%- set widget_disabled_class = widget_disabled_class|default('my disabled widget classes') -%}
+        {%- set widget_errors_class = widget_errors_class|default('my widget with error classes') -%}
+        {{- parent() -}}
+    {%- endblock widget_attributes -%}
+
+    {%- block form_label -%}
+        {%- set label_class = label_class|default('my label classes') -%}
+        {{- parent() -}}
+    {%- endblock form_label -%}
+
+    {%- block form_help -%}
+        {%- set help_class = help_class|default('my label classes') -%}
+        {{- parent() -}}
+    {%- endblock form_help -%}
+
+    {%- block form_errors -%}
+        {%- set error_item_class = error_item_class|default('my error item classes') -%}
+        {{- parent() -}}
+    {%- endblock form_errors -%}
+
+.. _`Tailwind CSS`: https://tailwindcss.com
+.. _`form plugin`: https://github.com/tailwindlabs/tailwindcss-forms

forms.rst

@@ -1029,6 +1029,7 @@ Form Themes and Customization:
 
     /form/bootstrap4
     /form/bootstrap5
+    /form/tailwindcss
     /form/form_customization
     /form/form_themes