1. A method comprising: receiving, by one or more computer devices, a search query from a client, the search query including a plurality of terms entered by a user of the client, the plurality of terms including: a first term related to a topic of a web page, a second term related to a first keyword of a plurality of keywords, a third term related to a second keyword of the plurality of keywords, the plurality of keywords corresponding to a plurality of visual features, the plurality of visual features including: a color of a background of the web page, a feature relating to an image in the web page, and at least one of: a color or a size of text in the web page, or a feature relating to a video in the web page, the first keyword relating to a first visual feature of the plurality of visual features, the second keyword relating to a second visual feature of the plurality of visual features, one of the first visual feature or the second visual feature including the color of the background of the web page, and a fourth term to be searched in relation to the one of the first visual feature or the second visual feature, an index associating the plurality of keywords with information identifying the web page; converting, by the one or more computer devices, a format of the second term to a format of the first keyword in the index when the format of the second term does not match the format of the first keyword; identifying, by the one or more computer devices, documents based on the search query and using the index, the identified documents including the web page; and providing, by the one or more computer devices, a search results document to the client, the search results document identifying one or more of the identified documents.