Problem styling 3rd Parts Polymer Component

i included the polymer component [paper-swatch-picker]

Now, I am trying to customize the style of the displayed component. It consists of serveral other components (paper-menu-button, paper-icon-button, iron-icon).

How can I style child elements of the paper-swatch-picker?


For changing a button text color I tried the following (which is not working)

@CssImport(value = "./styles/components/paper-icon-button.css", themeFor = "paper-icon-button")
:host {
     color: red !important;