1. A method comprising: receiving an affiliate preference that specifies a particular visual theme for an affiliate of a search engine, the affiliate being an entity different from the search engine; receiving a request for search results by the search engine, where the request includes a search query submitted in an input field by a user, wherein the input field is included in a web page, wherein the web page is provided by the affiliate, wherein the web page includes content of the affiliate, and wherein the request includes an affiliate identifier identifying the affiliate; obtaining a search results page in response to the search query; identifying one or more features of the search query; selecting a first visual theme from among a plurality of visual themes based on the first visual theme having trigger data matching the affiliate identifier, where each visual theme has respective trigger data, based on the one or more features of the search query matching the trigger data of the first visual theme, the first visual theme having theme data, the theme data specifying visual features; and applying the visual features to the search results page for display in a user interface.