I have a Polymer component that uses another component in its template (a buttons container). Said child component also uses another component (the button itself) and I need to add some style to that button when it is disabled. Something like this:

```
<dom-module id="parent-component">
  <template>
    ... template elements
        <confirm-buttons-container id="child-component" config$="[[someConfigVariable]]" ></confirm-buttons-container>

  </template>
</dom-module>

```

And the child component is something like this:

```
<dom-module id="confirm-buttons-container">
  <template>
      <dom-if if="[[config.buttons.primary]]">
        <template>
          <grandchild-component-button class$="[[config.buttons.primary.class]]">
            <button
              id="primaryBtn"
              name="primary"
              inner-h-t-m-l="[[t(config.buttons.primary.text)]]"
              disabled$="[[config.buttons.primary.disabled]]">
            </button>
          </grandchild-component-button>
        </template>
      </dom-if>
  </template>
</dom-module>

```

The child component has a mixin that styles the grandchild component, that also has a mixin that styles the property I want to change. How can I reach said mixin from the parent-component when config.buttons.primary.disabled is true 

Thanks in advance for any help.