If you do not want all the column headers to be aligned the same way, you can also define individual css classes using the headerCssClass attribute of the column definition , for example:
var columns = [ {id: "title", name: "Title", field: "title", headerCssClass: 'text'}, {id: "price", name: "Price", field: "price", headerCssClass: 'currency'} ];
and
.slick-header-column.currency { text-align: center; }
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