ionic color
<ion-button>Default</ion-button>
<ion-button color="primary">Primary</ion-button>
<ion-button color="secondary">Secondary</ion-button>
<ion-button color="tertiary">Tertiary</ion-button>
<ion-button color="success">Success</ion-button>
<ion-button color="warning">Warning</ion-button>
<ion-button color="danger">Danger</ion-button>
<ion-button color="light">Light</ion-button>
<ion-button color="medium">Medium</ion-button>
<ion-button color="dark">Dark</ion-button>