How to custom style of vaadin-date-picker encapsulated in other web compone


I have a custom web components library. I need a text field for manage date input.
So, I thought to use vaadin-date-picker inside my web component.
It works fine.
Now I have to custom visualization style, so the component will be similar to others in my library.
My web component library is a stencil library, written using typescript.

The component is created during render method like this:

<Host><div id="kup-component"><vaadin-date-picker
	clear-button-visible={isClearable ? true : null}

During componentWillLoad() method I added to the DOM:

<dom-module id="custom-input-field-style" theme-for="vaadin-text-field">
				border: 1px solid pink;
				background-color: white; }

When I inspect the resulting page, I can see the dom-module tag and its content correctly.
But the vaadin-date-picker component didn’t change style.

I tried to add dom-module first to the document.body, like first child.
Then I tried to add it to the shadowRoot of my custom component, like first child too.

Anything changes.

What can I do? Have you any suggestions?