You need to add the Creode packagist repository to the site as the packages are not publicly accessible through packagist.org. Add the following lines just above the "require" statement within your project's composer.json file:

"repositories": [
    {
        "type": "composer",
        "url": "https://packages.creode.dev"
    }
],

Tip: If you need assistance or further details about the repositories settings within Composer you can find additional information in their documentation.

Composer

Install the plugin via Composer from your project root:

composer require creode-mosaic/admin-style