firefox/styles/hacker-news-algolia.css

@-moz-document domain("hn.algolia.com") { 
  body,
  .SearchFilters,
  .SearchHeader_search,
  .SearchHeader .SearchInput,
  .SearchResults,
  .Pagination {
    background-color: hsl(218deg 14% 18%);
  }
  
  .Story_title a {
    color: hsl(218deg 14% 43%);
  }
  
  li.Pagination_item-current button {
    color: hsl(218deg 14% 46%);
    border-color: hsl(218deg 14% 36%);
  }

  .SearchFilters_filters label,
  .Pagination_item button {
    border-color: hsl(218deg 14% 27%);
  }

  .SearchHeader .SearchIcon,
  .Footer, .Footer a,
  .SearchInput::placeholder,
  .Pagination_item button,
  .SearchHeader_settings a,
  .SearchFilters,
  .Dropdown_label,
  .Story_title .Story_link,
  .Story_meta, .Story_meta a,
  .Story_comment {
    color: hsl(218deg 14% 33%);
  }

  .SearchHeader_label,
  .SearchHeader_logo,
  .PoweredBy img {
    display: none;
  }
}