Unable to change header background color, Using version Beta4

Ionic Framework
1

Tried so many solution but still helpless. How to change header background color?

2

Try:

<ion-header>
  <ion-toolbar color="primary">
    <ion-title>Files</ion-title>
  </ion-toolbar>
</ion-header>

13

Or:

<ion-header>
  <ion-toolbar color="success">
    <ion-title>Files</ion-title>
  </ion-toolbar>
</ion-header>

58