How could I change CSS Style tag dynamically?

Summary:

Content (required):

I tried using the return of a string function containing CSS Style and I tried using it dynamically in the :style tag, but with no success. I also tried to create a variable containing the string "background-color:#FFA722;" and again the Style tag did not receive the content.

This way it didn't work:

<a target="_parent" on-dblclick="[[$listeners.hyperlinkDblclick]]" class="cell-link-a"

  :style="[[$page.functions.billingSteps($variables.billingStepsCodeADP)]]" >

                  <oj-bind-text value="[[$current.data]]"></oj-bind-text>

  </a>

Is there any way to dynamically change the :style tag?

I got it only when I directly change the class:

<a target="_parent" on-dblclick="[[$listeners.hyperlinkDblclick]]"