How to style one header column

[palmtreefrb]

Below is my attempt to style "one" column but it is not working. Can someone provide the correct way to achieve header column styling.

<mtx-grid [data]="list"
          [columns]="columns"
          [loading]="isLoading"
          [pageOnFront]="showPaginator"
          [showPaginator]="showPaginator"
          [pageSizeOptions]="[5,10,50,100]"
          [pageIndex]="0"
          [pageSize]="5"
          [headerTemplate]="{activecol: activeTpl}">>
</mtx-grid>

<ng-template #activeTpl let-col>
  <span class="active_header">{{col.activecol}}</span>
</ng-template>

[palmtreefrb]

Never mind, I figured it out.