Why css files working in local laravel but not in heroku?

I have Laravel app.

I am referencing a CSS file.

The file is inside a public folder, css app.

it is working fine locally when deploying to heroku, it says 404.

web: vendor/bin/heroku-php-apache2 public/

and my .htcsss

is

<IfModule mod_rewrite.c>
    RewriteEngine on
    RewriteCond %{REQUEST_URI} !^public
    RewriteRule ^(.*)$ public/index.php?$1 [END,QSA]
</IfModule>

both in the root and under public folder.