How to squeeze the juice by removing the pulp (bootstrap)?

Question

Yii

I can't figure it out, or rather want to clarify.
In yii2, use boots 3 as the basis of the project. In fact, it can be stylized by removing unnecessary for development. But in fact, it is obligatory to leave css components like stylized buttons, forms, because. they have settings tied to it.
Is it possible to download the boots by downloading only the grid, forms and everything and somehow change the behavior. I can't figure out how to correctly rewrite the styles of a site tied to yii2 and boots. I know that you can set your own styles in the settings, but the question of how it will behave without them remains open. What do you advise?

Answer 1

Well, decide what widgets you need and

'assetManager' => [
    'bundles' => [
        'yii\bootstrap\BootstrapAsset' => [
            'css' => ['свой бутстрап'],
        ],
    ],
],