How to style vaadin-combo-box

Hello guys i need to style web component vaadin-text-field inside of vaadin-combo-box how to style it ? Any suggestion ?

See details here, what can be styled:

I.e. text-field, clear-button and toggle-button can be styled despite they are in shadow DOM.

The vaadin-text-field styling specs are here:

See also for generic info about ThemableMixin, which is our way to give styling options to things that would be otherwise protected by shadow DOM.