Remove Category Page Header

I found code in the forums... but it doesn't seem to be working on my site - so I must be doing something wrong.

I've added the following code with the "WP Add Custom CSS" plugin:

<!-- Remove Category Page Header -->

.category .page-header {
    display: none;
}

.category .page-title {
    display: none;
}

<!-- End Remove Category Page Header -->

The page title disappears - but the page header does not. Example page: http://www.artofboardgaming.com/category/gaming101/