Please take a look at our theming documentation:
- https://vaadin.com/docs/v13/flow/theme/theming-overview.html
- https://github.com/vaadin/vaadin-themable-mixin/blob/master/README.md
Basically you need to do something like:
<dom-module id="my-text-field" theme-for="vaadin-text-field">
<template>
<style>
:host([theme~="my-special-text-field"]
) [part="input-field"]
{
...
}
</style>
</template>
</dom-module>
And then set theme="my-special-text-field" attribute for the vaadin-combo-box (the special theme attribute is inherited by sub components).
If you’re using the Java API you can set the theme name like comboBox.addThemeName("my-special-text-field") otherwise it’s easy to set in an HTML template too.