Stylish is a free Mozilla extension that allows for the manipulation of web pages and XUL application user interfaces through the use of CSS[1]. The "userstyles", as they are called, are available locally or from centralized web-site [1], which allows style sharing. It is available for Mozilla Firefox, Mozilla Thunderbird, Google Chrome [2], and Flock.
... Odio los elementos fijos en una página. Me comen espacio en la pantalla y no aportan ninguna ventaja.