test.vue

Vue.swal({
    title: 'Are you sure?',
    text: 'Selecting another sub category will result in all selections being reset.',
    icon: 'warning',
    showCancelButton: true,
    confirmButtonText: 'Yes, clear selections',
    reverseButtons: true,
}).then((result) => {
    if (result.value) {
        // Button was accepted, do your thing
        let clearPreviousSubCategory = true;
        this.changeSubCategory(subCategoryId, clearPreviousSubCategory);
    }
});

And inside the vue CSS:

.swal2-popup {
    font-size: 1.6rem !important;
}

.swal2-confirm, .swal2-cancel {
    font-size: 1.8rem !important;
    padding: 8px 10px !important;
    margin: 4px 8px !important;
}