Rendering problem with the NelmioApiDocBundle

I have a problem with the bundle "NelmioApiDocBundle".

my rendering https://localhost:8000/api/doc

The rendering is raw when it should be much more design.

***routes.yaml***

api_login_check:
        path: /api/login_check

    app.swagger:
        path: /api/doc
        methods: GET
        defaults: { _controller: nelmio_api_doc.controller.swagger }

my bundles

***bundles.php***

return [
    Symfony\Bundle\FrameworkBundle\FrameworkBundle::class => ['all' => true],
    Symfony\Bundle\TwigBundle\TwigBundle::class => ['all' => true],
    Twig\Extra\TwigExtraBundle\TwigExtraBundle::class => ['all' => true],
    Sensio\Bundle\FrameworkExtraBundle\SensioFrameworkExtraBundle::class => ['all' => true],
    Doctrine\Bundle\DoctrineBundle\DoctrineBundle::class => ['all' => true],
    Doctrine\Bundle\MigrationsBundle\DoctrineMigrationsBundle::class => ['all' => true],
    Symfony\Bundle\SecurityBundle\SecurityBundle::class => ['all' => true],
    Symfony\Bundle\WebProfilerBundle\WebProfilerBundle::class => ['dev' => true, 'test' => true],
    Symfony\Bundle\MonologBundle\MonologBundle::class => ['all' => true],
    Symfony\Bundle\DebugBundle\DebugBundle::class => ['dev' => true, 'test' => true],
    Symfony\Bundle\MakerBundle\MakerBundle::class => ['dev' => true],
    Doctrine\Bundle\FixturesBundle\DoctrineFixturesBundle::class => ['dev' => true, 'test' => true],
    Lexik\Bundle\JWTAuthenticationBundle\LexikJWTAuthenticationBundle::class => ['all' => true],
    Nelmio\ApiDocBundle\NelmioApiDocBundle::class => ['all' => true],

];

Did you have this kind of problem?

Thanks