Each specific situation should have its own AssetBundle.
You just create as many as you need and include them in the relevant view file:
Existing one:
class AppAssets extends \yii\web\AssetBundle
{
public $basePath = '@webroot';
public $baseUrl = '@web';
public $css = ['css/site.css', 'css/country.css', 'css/fg/two.css'];
...
}
Additional one:
class AdminAssetBundle extends \yii\web\AssetBundle
{
public $basePath = '@webroot';
public $baseUrl = '@web';
public $css = ['css/admin/one.css'];
public $depends = ['AppAssets'],
}
(Please add namespaces where necessary, I left those out)
As said: Then just include the one you need in the view that is relevant.
ie. in your admin views you add: AdminAsset::register($this);
Because of the depends, those views will automatically include your AppAssets bundle.
If your AppAssets is the one from the yii app distribution (added by default), it is probably already being registered in the /views/layouts/main.php-file.
That means that it is not required to be defined as a dependency.
I do consider it a good practice to keep the dependencies clear (if your admin one.css file actually depends on the ones from AppAssets, if not remove the $depends alltogether).
Yii is smart enough to only include each asset bundle only once anyway.
