Set navbar background opacity or use rgba

Like the title says… i want to set opacity onn my header.
I have two projects. One of them using ionic 0.9.25 and the other one beta13.

I can set opacity with background: rgba in the project using 0.9.25. But the same way isn’t working in my second project using beta13.

My ion-nav-bar in index.html with class noBackground:

<ion-nav-bar class="nav-title-slide-ios7 bar-light noBackground">
    <ion-nav-back-button class="button-icon icon ion-ios7-arrow-back">

and my scss code:

.noBackground {
    background: rgba(255, 255, 255,0.3) !important;                         }

Thank you for your help!

EDIT: Didn’t solve this, but still can be closed. I don’t need to make the background transparent anymore. Ty.