Stylish is a browser extension that can apply a user-supplied style sheet to a web page, in addition to the Cascading Style Sheetsprovided by the website itself, to customize and personalize the appearance of the page. A user style may be more or less selective, targeting one specific web page, or several, or all of the pages on one or more domains, or every page on the web.
Mozilla-based web browsers (Firefox, Mozilla Thunderbird) and Chromium-based browsers (Google Chrome, Flock) are supported with two different implementations of the extension. A similar but unrelated extension provides the same functionality in Apple Safari. All can download and install stylesheets from a companion website, where members can upload and share their custom styles.