Ion-segment button activated text color is not changing?

<ion-segment [(ngModel)]="selectedcategory" color="blackcolor" >
  <ion-segment-button *ngFor=" let category of displayingCategories; let i=index; " [style.width]="category.width" (ionSelect)="categorySelect(category.category)"  value="category.category" >
    {{category.category}}
  </ion-segment-button>
</ion-segment>

below colors working fine when i am pressing that button but when i release it’s coming to again black color.

$segment-button-md-text-color-activated:#981F64;
$segment-button-md-border-color-activated:#981F64;

How can i change the background and below border color and text colour when the button is pressed.I mean after pressing also it’s needs to be in same color unless i change the button.?