/* Remove the search button and search field entirely */
.main-nav .search,
.main-nav .search-icon,
.main-nav .search-sub,
.main-nav .search-field,
.main-nav.open-search .search-sub {
  display: none !important;
}
<script async type="text/javascript" src="https://cdn.patchretention.com/pixel/690024/pixel.js"></script>