How to change the color of the first column of a ngx-datatable

I have a ngx-datatable like this:

<ngx-datatable
    class="material striped"
    [scrollbarV]="false"
    [scrollbarH]="true"
    [rows]="rows"
    [columns]="col"
    [rowHeight]="35"
    [headerHeight]="40"
  >
  </ngx-datatable>

How I change the color of the first column?