diff --git a/doc/functions/html_cva.rst b/doc/functions/html_cva.rst
new file mode 100644
index 000000000..70226e77b
--- /dev/null
+++ b/doc/functions/html_cva.rst
@@ -0,0 +1,185 @@
+``html_cva``
+============
+
+`CVA (Class Variant Authority)`_ is a concept from the JavaScript world and used
+by the well-known `shadcn/ui`_ library.
+The CVA concept is used to render multiple variations of components, applying
+a set of conditions and recipes to dynamically compose CSS class strings (color, size, etc.),
+to create highly reusable and customizable templates.
+
+The concept of CVA is powered by a ``html_cva()`` Twig
+function where you define ``base`` classes that should always be present and then different
+``variants`` and the corresponding classes:
+
+.. code-block:: html+twig
+
+    {# templates/alert.html.twig #}
+    {% set alert = html_cva(
+        base='alert ',
+        variants={
+            color: {
+                blue: 'bg-blue',
+                red: 'bg-red',
+                green: 'bg-green',
+            },
+            size: {
+                sm: 'text-sm',
+                md: 'text-md',
+                lg: 'text-lg',
+            }
+        }
+    ) %}
+
+    <div class="{{ alert.apply({color, size}, class) }}">
+        ...
+    </div>
+
+Then use the ``color`` and ``size`` variants to select the needed classes:
+
+.. code-block:: twig
+
+    {# index.html.twig #}
+    {{ include('alert.html.twig', {'color': 'blue', 'size': 'md'}) }}
+    // class="alert bg-red text-lg"
+
+    {{ include('alert.html.twig', {'color': 'green', 'size': 'sm'}) }}
+    // class="alert bg-green text-sm"
+
+    {{ include('alert.html.twig', {'color': 'red', 'class': 'flex items-center justify-center'}) }}
+    // class="alert bg-red text-md flex items-center justify-center"
+
+CVA and Tailwind CSS
+--------------------
+
+CVA work perfectly with Tailwind CSS. The only drawback is that you can have class conflicts.
+To "merge" conflicting classes together and keep only the ones you need, use the
+``tailwind_merge()`` filter from `tales-from-a-dev/twig-tailwind-extra`_
+with the ``html_cva()`` function:
+
+.. code-block:: terminal
+
+    $ composer require tales-from-a-dev/twig-tailwind-extra
+
+.. code-block:: html+twig
+
+    {% set alert = html_cva(
+       // ...
+    ) %}
+
+    <div class="{{ alert.apply({color, size}, class)|tailwind_merge }}">
+         ...
+    </div>
+
+Compound Variants
+-----------------
+
+You can define compound variants. A compound variant is a variant that applies
+when multiple other variant conditions are met:
+
+.. code-block:: html+twig
+
+    {% set alert = html_cva(
+        base='alert',
+        variants={
+            color: {
+                blue: 'bg-blue',
+                red: 'bg-red',
+                green: 'bg-green',
+            },
+            size: {
+                sm: 'text-sm',
+                md: 'text-md',
+                lg: 'text-lg',
+            }
+        },
+        compoundVariants=[{
+            // if color = red AND size = (md or lg), add the `font-bold` class
+            color: ['red'],
+            size: ['md', 'lg'],
+            class: 'font-bold'
+        }]
+    ) %}
+
+    <div class="{{ alert.apply({color, size}) }}">
+         ...
+    </div>
+
+    {# index.html.twig #}
+
+    {{ include('alert.html.twig', {color: 'red', size: 'lg'}) }}
+    // class="alert bg-red text-lg font-bold"
+
+    {{ include('alert.html.twig', {color: 'green', size: 'sm'}) }}
+    // class="alert bg-green text-sm"
+
+    {{ include('alert.html.twig', {color: 'red', size: 'md'}) }}
+    // class="alert bg-green text-lg font-bold"
+
+Default Variants
+----------------
+
+If no variants match, you can define a default set of classes to apply:
+
+.. code-block:: html+twig
+
+    {% set alert = html_cva(
+        base='alert ',
+        variants={
+            color: {
+                blue: 'bg-blue',
+                red: 'bg-red',
+                green: 'bg-green',
+            },
+            size: {
+                sm: 'text-sm',
+                md: 'text-md',
+                lg: 'text-lg',
+            },
+            rounded: {
+                sm: 'rounded-sm',
+                md: 'rounded-md',
+                lg: 'rounded-lg',
+            }
+        },
+        defaultVariants={
+            rounded: 'md',
+        }
+    ) %}
+
+    <div class="{{ alert.apply({color, size}) }}">
+         ...
+    </div>
+
+    {# index.html.twig #}
+
+    {{ include('alert.html.twig', {color: 'red', size: 'lg'}) }}
+    // class="alert bg-red text-lg font-bold rounded-md"
+
+.. note::
+
+    The ``html_cva`` function is part of the ``HtmlExtension`` which is not
+    installed by default. Install it first:
+
+    .. code-block:: bash
+
+        $ composer require twig/html-extra
+
+    Then, on Symfony projects, install the ``twig/extra-bundle``:
+
+    .. code-block:: bash
+
+            $ composer require twig/extra-bundle
+
+    Otherwise, add the extension explicitly on the Twig environment::
+
+            use Twig\Extra\Html\HtmlExtension;
+
+            $twig = new \Twig\Environment(...);
+            $twig->addExtension(new HtmlExtension());
+
+This function works best when used with `TwigComponent`_.
+
+.. _`CVA (Class Variant Authority)`: https://cva.style/docs/getting-started/variants
+.. _`shadcn/ui`: https://ui.shadcn.com
+.. _`tales-from-a-dev/twig-tailwind-extra`: https://github.com/tales-from-a-dev/twig-tailwind-extra
+.. _`TwigComponent`: https://symfony.com/bundles/ux-twig-component/current/index.html
\ No newline at end of file
diff --git a/extra/html-extra/Cva.php b/extra/html-extra/Cva.php
new file mode 100644
index 000000000..a77d7dfdf
--- /dev/null
+++ b/extra/html-extra/Cva.php
@@ -0,0 +1,129 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Extra\Html;
+
+/**
+ * Class Variant Authority (CVA) resolver.
+ *
+ * @author Mathéo Daninos <matheo.daninos@gmail.com>
+ */
+final class Cva
+{
+    /**
+     * @var list<string|null>
+     */
+    private array $base;
+
+    /**
+     * @param string|list<string|null> $base The base classes to apply to the component
+     */
+    public function __construct(
+        string|array $base = [],
+        /**
+         * The variants to apply based on recipes.
+         *
+         * Format: [variantCategory => [variantName => classes]]
+         *
+         * Example:
+         *      'colors' => [
+         *          'primary' => 'bleu-8000',
+         *          'danger' => 'red-800 text-bold',
+         *       ],
+         *      'size' => [...],
+         *
+         * @var array<string, array<string, string|list<string>>>
+         */
+        private array $variants = [],
+
+        /**
+         * The compound variants to apply based on recipes.
+         *
+         * Format: [variantsCategory => ['variantName', 'variantName'], class: classes]
+         *
+         * Example:
+         *   [
+         *      'colors' => ['primary'],
+         *      'size' => ['small'],
+         *      'class' => 'text-red-500',
+         *   ],
+         *   [
+         *      'size' => ['large'],
+         *      'class' => 'font-weight-500',
+         *   ]
+         *
+         * @var array<array<string, string|array<string>>>
+         */
+        private array $compoundVariants = [],
+
+        /**
+         * The default variants to apply if specific recipes aren't provided.
+         *
+         * Format: [variantCategory => variantName]
+         *
+         * Example:
+         *     'colors' => 'primary',
+         *
+         * @var array<string, string>
+         */
+        private array $defaultVariants = [],
+    ) {
+        $this->base = (array) $base;
+    }
+
+    public function apply(array $recipes, ?string ...$additionalClasses): string
+    {
+        $classes = $this->base;
+
+        // Resolve recipes against variants
+        foreach ($recipes as $recipeName => $recipeValue) {
+            if (\is_bool($recipeValue)) {
+                $recipeValue = $recipeValue ? 'true' : 'false';
+            }
+            $recipeClasses = $this->variants[$recipeName][$recipeValue] ?? [];
+            $classes = [...$classes, ...(array) $recipeClasses];
+        }
+
+        // Resolve compound variants
+        foreach ($this->compoundVariants as $compound) {
+            $compoundClasses = $this->resolveCompoundVariant($compound, $recipes) ?? [];
+            $classes = [...$classes, ...$compoundClasses];
+        }
+
+        // Apply default variants if specific recipes aren't provided
+        foreach ($this->defaultVariants as $defaultVariantName => $defaultVariantValue) {
+            if (!isset($recipes[$defaultVariantName])) {
+                $variantClasses = $this->variants[$defaultVariantName][$defaultVariantValue] ?? [];
+                $classes = [...$classes, ...(array) $variantClasses];
+            }
+        }
+        $classes = [...$classes, ...array_values($additionalClasses)];
+
+        $classes = implode(' ', array_filter($classes, 'is_string'));
+        $classes = preg_split('#\s+#', $classes, -1, \PREG_SPLIT_NO_EMPTY) ?: [];
+
+        return implode(' ', array_unique($classes));
+    }
+
+    private function resolveCompoundVariant(array $compound, array $recipes): array
+    {
+        foreach ($compound as $compoundName => $compoundValues) {
+            if ('class' === $compoundName) {
+                continue;
+            }
+            if (!isset($recipes[$compoundName]) || !\in_array($recipes[$compoundName], (array) $compoundValues)) {
+                return [];
+            }
+        }
+
+        return (array) ($compound['class'] ?? []);
+    }
+}
diff --git a/extra/html-extra/HtmlExtension.php b/extra/html-extra/HtmlExtension.php
index 83fcc58b1..06329977f 100644
--- a/extra/html-extra/HtmlExtension.php
+++ b/extra/html-extra/HtmlExtension.php
@@ -37,6 +37,7 @@ final class HtmlExtension extends AbstractExtension
     {
         return [
             new TwigFunction('html_classes', [self::class, 'htmlClasses']),
+            new TwigFunction('html_cva', [self::class, 'htmlCva']),
         ];
     }
 
@@ -110,4 +111,17 @@ final class HtmlExtension extends AbstractExtension
 
         return implode(' ', array_unique(array_filter($classes, static function ($v) { return '' !== $v; })));
     }
+
+    /**
+     * @param string|list<string|null> $base
+     * @param array<string, array<string, string|array<string>> $variants
+     * @param array<array<string, string|array<string>>> $compoundVariants
+     * @param array<string, string> $defaultVariant
+     *
+     * @internal
+     */
+    public static function htmlCva(array|string $base = [], array $variants = [], array $compoundVariants = [], array $defaultVariant = []): Cva
+    {
+        return new Cva($base, $variants, $compoundVariants, $defaultVariant);
+    }
 }
diff --git a/extra/html-extra/README.md b/extra/html-extra/README.md
index e2c46b08e..9cd51fe28 100644
--- a/extra/html-extra/README.md
+++ b/extra/html-extra/README.md
@@ -9,5 +9,8 @@ This package is a Twig extension that provides the following:
  * [`html_classes`][2] function: returns a string by conditionally joining class
    names together.
 
+ * [`html_cva`][3] function: returns a `Cva` object to handle class variants.
+
 [1]: https://twig.symfony.com/data_uri
 [2]: https://twig.symfony.com/html_classes
+[3]: https://twig.symfony.com/html_cva
diff --git a/extra/html-extra/Tests/CvaTest.php b/extra/html-extra/Tests/CvaTest.php
new file mode 100644
index 000000000..b8b32fbef
--- /dev/null
+++ b/extra/html-extra/Tests/CvaTest.php
@@ -0,0 +1,668 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Extra\Html\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Twig\Extra\Html\Cva;
+
+class CvaTest extends TestCase
+{
+    /**
+     * @dataProvider recipeProvider
+     */
+    public function testRecipes(array $recipe, array $recipes, string $expected)
+    {
+        $recipeClass = new Cva($recipe['base'] ?? '', $recipe['variants'] ?? [], $recipe['compounds'] ?? [], $recipe['defaultVariants'] ?? []);
+
+        $this->assertEquals($expected, $recipeClass->apply($recipes));
+    }
+
+    public function testApply()
+    {
+        $recipe = new Cva('font-semibold border rounded', [
+            'colors' => [
+                'primary' => 'text-primary',
+                'secondary' => 'text-secondary',
+            ],
+            'sizes' => [
+                'sm' => 'text-sm',
+                'md' => 'text-md',
+                'lg' => 'text-lg',
+            ],
+        ], [
+            [
+                'colors' => ['primary'],
+                'sizes' => ['sm'],
+                'class' => 'text-red-500',
+            ],
+        ]);
+
+        $this->assertEquals('font-semibold border rounded text-primary text-sm text-red-500', $recipe->apply(['colors' => 'primary', 'sizes' => 'sm']));
+    }
+
+    public function testApplyWithNullString()
+    {
+        $recipe = new Cva('font-semibold border rounded', [
+            'colors' => [
+                'primary' => 'text-primary',
+                'secondary' => 'text-secondary',
+            ],
+            'sizes' => [
+                'sm' => 'text-sm',
+                'md' => 'text-md',
+                'lg' => 'text-lg',
+            ],
+        ], [
+            [
+                'colors' => ['primary'],
+                'sizes' => ['sm'],
+                'class' => 'text-red-500',
+            ],
+        ]);
+
+        $this->assertEquals('font-semibold border rounded text-primary text-sm text-red-500 flex justify-center', $recipe->apply(['colors' => 'primary', 'sizes' => 'sm'], 'flex', null, 'justify-center'));
+    }
+
+    public static function recipeProvider(): iterable
+    {
+        yield 'base null' => [
+            ['variants' => [
+                'colors' => [
+                    'primary' => 'text-primary',
+                    'secondary' => 'text-secondary',
+                ],
+                'sizes' => [
+                    'sm' => 'text-sm',
+                    'md' => 'text-md',
+                    'lg' => 'text-lg',
+                ],
+            ]],
+            ['colors' => 'primary', 'sizes' => 'sm'],
+            'text-primary text-sm',
+        ];
+
+        yield 'base empty' => [
+            [
+                'base' => '',
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                ]],
+            ['colors' => 'primary', 'sizes' => 'sm'],
+            'text-primary text-sm',
+        ];
+
+        yield 'base array' => [
+            [
+                'base' => ['font-semibold', 'border', 'rounded'],
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                ]],
+            ['colors' => 'primary', 'sizes' => 'sm'],
+            'font-semibold border rounded text-primary text-sm',
+        ];
+
+        yield 'no recipes match' => [
+            [
+                'base' => 'font-semibold border rounded',
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                ],
+            ],
+            ['colors' => 'red', 'sizes' => 'test'],
+            'font-semibold border rounded',
+        ];
+
+        yield 'simple variants' => [
+            [
+                'base' => 'font-semibold border rounded',
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'sizes' => 'sm'],
+            'font-semibold border rounded text-primary text-sm',
+        ];
+
+        yield 'simple variants as array' => [
+            [
+                'base' => 'font-semibold border rounded',
+                'variants' => [
+                    'colors' => [
+                        'primary' => ['text-primary', 'uppercase'],
+                        'secondary' => ['text-secondary', 'uppercase'],
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'sizes' => 'sm'],
+            'font-semibold border rounded text-primary uppercase text-sm',
+        ];
+
+        yield 'simple variants with custom' => [
+            [
+                'base' => 'font-semibold border rounded',
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                ],
+            ],
+            ['colors' => 'secondary', 'sizes' => 'md'],
+            'font-semibold border rounded text-secondary text-md',
+        ];
+
+        yield 'compound variants' => [
+            [
+                'base' => 'font-semibold border rounded',
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                ],
+                'compounds' => [
+                    [
+                        'colors' => 'primary',
+                        'sizes' => ['sm'],
+                        'class' => 'text-red-100',
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'sizes' => 'sm'],
+            'font-semibold border rounded text-primary text-sm text-red-100',
+        ];
+
+        yield 'compound variants with true' => [
+            [
+                'base' => 'button',
+                'variants' => [
+                    'colors' => [
+                        'blue' => 'btn-blue',
+                        'red' => 'btn-red',
+                    ],
+                    'disabled' => [
+                        'true' => 'disabled',
+                    ],
+                ],
+                'compounds' => [
+                    [
+                        'colors' => 'blue',
+                        'disabled' => ['true'],
+                        'class' => 'font-bold',
+                    ],
+                ],
+            ],
+            ['colors' => 'blue', 'disabled' => 'true'],
+            'button btn-blue disabled font-bold',
+        ];
+
+        yield 'compound variants as array' => [
+            [
+                'base' => 'font-semibold border rounded',
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                ],
+                'compounds' => [
+                    [
+                        'colors' => ['primary'],
+                        'sizes' => ['sm'],
+                        'class' => ['text-red-900', 'bold'],
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'sizes' => 'sm'],
+            'font-semibold border rounded text-primary text-sm text-red-900 bold',
+        ];
+
+        yield 'multiple compound variants' => [
+            [
+                'base' => 'font-semibold border rounded',
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                ],
+                'compounds' => [
+                    [
+                        'colors' => ['primary'],
+                        'sizes' => ['sm'],
+                        'class' => 'text-red-300',
+                    ],
+                    [
+                        'colors' => ['primary'],
+                        'sizes' => ['md'],
+                        'class' => 'text-blue-300',
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'sizes' => 'sm'],
+            'font-semibold border rounded text-primary text-sm text-red-300',
+        ];
+
+        yield 'compound with multiple variants' => [
+            [
+                'base' => 'font-semibold border rounded',
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                ],
+                'compounds' => [
+                    [
+                        'colors' => ['primary', 'secondary'],
+                        'sizes' => ['sm'],
+                        'class' => 'text-red-800',
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'sizes' => 'sm'],
+            'font-semibold border rounded text-primary text-sm text-red-800',
+        ];
+
+        yield 'compound doesn\'t match' => [
+            [
+                'base' => 'font-semibold border rounded',
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                ],
+                'compounds' => [
+                    [
+                        'colors' => ['danger', 'secondary'],
+                        'sizes' => ['sm'],
+                        'class' => 'text-red-500',
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'sizes' => 'sm'],
+            'font-semibold border rounded text-primary text-sm',
+        ];
+
+        yield 'default variables' => [
+            [
+                'base' => 'font-semibold border rounded',
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                    'rounded' => [
+                        'sm' => 'rounded-sm',
+                        'md' => 'rounded-md',
+                        'lg' => 'rounded-lg',
+                    ],
+                ],
+                'compounds' => [
+                    [
+                        'colors' => ['danger', 'secondary'],
+                        'sizes' => 'sm',
+                        'class' => 'text-red-500',
+                    ],
+                ],
+                'defaultVariants' => [
+                    'colors' => 'primary',
+                    'sizes' => 'sm',
+                    'rounded' => 'md',
+                ],
+            ],
+            ['colors' => 'primary', 'sizes' => 'sm'],
+            'font-semibold border rounded text-primary text-sm rounded-md',
+        ];
+
+        yield 'default variables all overwrite' => [
+            [
+                'base' => 'font-semibold border rounded',
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                    'rounded' => [
+                        'sm' => 'rounded-sm',
+                        'md' => 'rounded-md',
+                        'lg' => 'rounded-lg',
+                    ],
+                ],
+                'compounds' => [
+                    [
+                        'colors' => ['danger', 'secondary'],
+                        'sizes' => ['sm'],
+                        'class' => 'text-red-500',
+                    ],
+                ],
+                'defaultVariants' => [
+                    'colors' => 'primary',
+                    'sizes' => 'sm',
+                    'rounded' => 'md',
+                ],
+            ],
+            ['colors' => 'primary', 'sizes' => 'sm', 'rounded' => 'lg'],
+            'font-semibold border rounded text-primary text-sm rounded-lg',
+        ];
+
+        yield 'default variables without matching variants' => [
+            [
+                'base' => 'font-semibold border rounded',
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'sizes' => [
+                        'sm' => 'text-sm',
+                        'md' => 'text-md',
+                        'lg' => 'text-lg',
+                    ],
+                    'rounded' => [
+                        'sm' => 'rounded-sm',
+                        'md' => 'rounded-md',
+                        'lg' => 'rounded-lg',
+                    ],
+                ],
+                'compounds' => [
+                    [
+                        'colors' => ['danger', 'secondary'],
+                        'sizes' => ['sm'],
+                        'class' => 'text-red-500',
+                    ],
+                ],
+                'defaultVariants' => [
+                    'colors' => 'primary',
+                    'sizes' => 'sm',
+                    'rounded' => 'md',
+                ],
+            ],
+            [],
+            'font-semibold border rounded text-primary text-sm rounded-md',
+        ];
+
+        yield 'default variables with boolean' => [
+            [
+                'base' => 'button',
+                'variants' => [
+                    'colors' => [
+                        'blue' => 'btn-blue',
+                        'red' => 'btn-red',
+                    ],
+                    'disabled' => [
+                        'true' => 'disabled',
+                        'false' => 'opacity-100',
+                    ],
+                ],
+                'defaultVariants' => [
+                    'colors' => 'blue',
+                    'disabled' => 'false',
+                ],
+            ],
+            [],
+            'button btn-blue opacity-100',
+        ];
+
+        yield 'boolean string variants true / true' => [
+            [
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'disabled' => [
+                        'true' => 'disable',
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'disabled' => true],
+            'text-primary disable',
+        ];
+
+        yield 'boolean string variants true / false' => [
+            [
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'disabled' => [
+                        'true' => 'disable',
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'disabled' => false],
+            'text-primary',
+        ];
+
+        yield 'boolean string variants false / true' => [
+            [
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'disabled' => [
+                        'false' => 'disable',
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'disabled' => true],
+            'text-primary',
+        ];
+
+        yield 'boolean string variants false / false' => [
+            [
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'disabled' => [
+                        'false' => 'disable',
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'disabled' => false],
+            'text-primary disable',
+        ];
+
+        yield 'boolean string variants missing' => [
+            [
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'disabled' => [
+                        'true' => 'disable',
+                    ],
+                ],
+            ],
+            ['colors' => 'primary'],
+            'text-primary',
+        ];
+
+        yield 'boolean list variants true' => [
+            [
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'disabled' => [
+                        'true' => ['disable', 'opacity-50'],
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'disabled' => true],
+            'text-primary disable opacity-50',
+        ];
+
+        yield 'boolean list variants false' => [
+            [
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'disabled' => [
+                        'true' => ['disable', 'opacity-50'],
+                    ],
+                ],
+            ],
+            ['colors' => 'primary', 'disabled' => false],
+            'text-primary',
+        ];
+
+        yield 'boolean list variants missing' => [
+            [
+                'variants' => [
+                    'colors' => [
+                        'primary' => 'text-primary',
+                        'secondary' => 'text-secondary',
+                    ],
+                    'disabled' => [
+                        'true' => ['disable', 'opacity-50'],
+                    ],
+                ],
+            ],
+            ['colors' => 'primary'],
+            'text-primary',
+        ];
+    }
+
+    /**
+     * @dataProvider provideAdditionalClassesCases
+     */
+    public function testAdditionalClasses(string|array $base, array|string $additionals, string $expected)
+    {
+        $cva = new Cva($base);
+        if (!$additionals) {
+            $this->assertEquals($expected, $cva->apply([]));
+        } else {
+            $this->assertEquals($expected, $cva->apply([], ...(array) $additionals));
+        }
+    }
+
+    public static function provideAdditionalClassesCases(): iterable
+    {
+        yield 'additionals_are_optional' => [
+            '',
+            'foo',
+            'foo',
+        ];
+
+        yield 'additional_are_used' => [
+            '',
+            'foo',
+            'foo',
+        ];
+
+        yield 'additionals_are_used' => [
+            '',
+            ['foo', 'bar'],
+            'foo bar',
+        ];
+
+        yield 'additionals_preserve_order' => [
+            ['foo'],
+            ['bar', 'foo'],
+            'foo bar',
+        ];
+
+        yield 'additional_are_deduplicated' => [
+            '',
+            ['bar', 'bar'],
+            'bar',
+        ];
+    }
+}
diff --git a/extra/html-extra/Tests/Fixtures/html_cva.test b/extra/html-extra/Tests/Fixtures/html_cva.test
new file mode 100644
index 000000000..71e16036a
--- /dev/null
+++ b/extra/html-extra/Tests/Fixtures/html_cva.test
@@ -0,0 +1,37 @@
+--TEST--
+"html_cva" function
+--TEMPLATE--
+{% set alert = html_cva(
+    ['alert'],
+    {
+       color: {
+           blue: 'alert-blue',
+           red: 'alert-red',
+           green: 'alert-green',
+           yellow: 'alert-yellow',
+       },
+       size: {
+           sm: 'alert-sm',
+           md: 'alert-md',
+           lg: 'alert-lg',
+       },
+       rounded: {
+           sm: 'rounded-sm',
+           md: 'rounded-md',
+           lg: 'rounded-lg',
+       }
+    },
+    [{
+       color: ['red'],
+       size: ['lg'],
+       class: 'font-semibold'
+    }],
+    {
+       rounded: 'md'
+    }
+) %}
+{{ alert.apply({color: 'blue', size: 'sm'}) }}
+--DATA--
+return []
+--EXPECT--
+alert alert-blue alert-sm rounded-md
diff --git a/extra/html-extra/Tests/Fixtures/html_cva_pass_to_template.test b/extra/html-extra/Tests/Fixtures/html_cva_pass_to_template.test
new file mode 100644
index 000000000..49b842fac
--- /dev/null
+++ b/extra/html-extra/Tests/Fixtures/html_cva_pass_to_template.test
@@ -0,0 +1,19 @@
+--TEST--
+pass Cva object to template
+--TEMPLATE--
+{{ alert.apply({colors: 'primary', sizes: 'sm'}) }}
+--DATA--
+return [
+    'alert' => new Twig\Extra\Html\Cva('font-semibold border rounded', [
+        'colors' => [
+            'primary' => 'text-primary',
+            'secondary' => 'text-secondary'
+        ],
+        'sizes' => [
+            'sm' => 'text-sm',
+            'lg' => 'text-lg'
+        ]
+    ])
+];
+--EXPECT--
+font-semibold border rounded text-primary text-sm